avr-g++ (1)





NAME

       gcc - GNU project C and C++ compiler


SYNOPSIS

       gcc [-c|-S|-E] [-std=standard]
           [-g] [-pg] [-Olevel]
           [-Wwarn...] [-pedantic]
           [-Idir...] [-Ldir...]
           [-Dmacro[=defn]...] [-Umacro]
           [-foption...] [-mmachine-option...]
           [-o outfile] infile...

       Only the most useful options are listed here; see below for the remain-
       der.  g++ accepts mostly the same options as gcc.


DESCRIPTION

       When you invoke GCC, it normally does preprocessing, compilation,
       assembly and linking.  The ``overall options'' allow you to stop this
       process at an intermediate stage.  For example, the -c option says not
       to run the linker.  Then the output consists of object files output by
       the assembler.

       Other options are passed on to one stage of processing.  Some options
       control the preprocessor and others the compiler itself.  Yet other
       options control the assembler and linker; most of these are not docu-
       mented here, since you rarely need to use any of them.

       Most of the command line options that you can use with GCC are useful
       for C programs; when an option is only useful with another language
       (usually C++), the explanation says so explicitly.  If the description
       for a particular option does not mention a source language, you can use
       that option with all supported languages.

       The gcc program accepts options and file names as operands.  Many
       options have multi-letter names; therefore multiple single-letter
       options may not be grouped: -dr is very different from -d -r.

       You can mix options and other arguments.  For the most part, the order
       you use doesn't matter.  Order does matter when you use several options
       of the same kind; for example, if you specify -L more than once, the
       directories are searched in the order specified.

       Many options have long names starting with -f or with -W---for example,
       -fforce-mem, -fstrength-reduce, -Wformat and so on.  Most of these have
       both positive and negative forms; the negative form of -ffoo would be
       -fno-foo.  This manual documents only one of these two forms, whichever
       one is not the default.


OPTIONS

       Option Summary

       Here is a summary of all the options, grouped by type.  Explanations
       are in the following sections.

       Overall Options
           -fwritable-strings

       C++ Language Options
           -fno-access-control  -fcheck-new  -fconserve-space
           -fno-const-strings  -fdollars-in-identifiers -fno-elide-construc-
           tors -fno-enforce-eh-specs  -fexternal-templates -falt-exter-
           nal-templates -ffor-scope  -fno-for-scope  -fno-gnu-keywords
           -fno-implicit-templates -fno-implicit-inline-templates -fno-imple-
           ment-inlines  -fms-extensions -fno-nonansi-builtins  -fno-opera-
           tor-names -fno-optional-diags  -fpermissive -frepo  -fno-rtti
           -fstats  -ftemplate-depth-n -fuse-cxa-atexit  -fvtable-gc
           -fno-weak  -nostdinc++ -fno-default-inline -Wabi -Wctor-dtor-pri-
           vacy -Wnon-virtual-dtor  -Wreorder -Weffc++  -Wno-deprecated
           -Wno-non-template-friend  -Wold-style-cast -Woverloaded-virtual
           -Wno-pmf-conversions -Wsign-promo  -Wsynth

       Objective-C Language Options
           -fconstant-string-class=class-name -fgnu-runtime  -fnext-runtime
           -gen-decls -Wno-protocol  -Wselector

       Language Independent Options
           -fmessage-length=n -fdiagnostics-show-location=[once|every-line]

       Warning Options
           -fsyntax-only  -pedantic  -pedantic-errors -w  -W  -Wall -Waggre-
           gate-return -Wcast-align  -Wcast-qual  -Wchar-subscripts  -Wcomment
           -Wconversion  -Wno-deprecated-declarations -Wdisabled-optimization
           -Wdiv-by-zero  -Werror -Wfloat-equal  -Wformat  -Wformat=2 -Wfor-
           mat-nonliteral  -Wformat-security -Wimplicit  -Wimplicit-int -Wim-
           plicit-function-declaration -Werror-implicit-function-declaration
           -Wimport  -Winline -Wlarger-than-len  -Wlong-long -Wmain  -Wmiss-
           ing-braces -Wmissing-format-attribute  -Wmissing-noreturn -Wmulti-
           char  -Wno-format-extra-args  -Wno-format-y2k -Wno-import  -Wpacked
           -Wpadded -Wparentheses  -Wpointer-arith  -Wredundant-decls -Wre-
           turn-type  -Wsequence-point  -Wshadow -Wsign-compare  -Wswitch
           -Wsystem-headers -Wtrigraphs  -Wundef  -Wuninitialized -Wun-
           known-pragmas  -Wunreachable-code -Wunused  -Wunused-function
           -Wunused-label  -Wunused-parameter -Wunused-value  -Wunused-vari-
           able  -Wwrite-strings

       C-only Warning Options
           -Wbad-function-cast  -Wmissing-declarations -Wmissing-prototypes
           -Wnested-externs -Wstrict-prototypes  -Wtraditional

       Debugging Options
           -dletters  -dumpspecs  -dumpmachine  -dumpversion -fdump-unnumbered
           -fdump-translation-unit[-n] -fdump-class-hierarchy[-n]
           -fdump-tree-original[-n] -fdump-tree-optimized[-n]
           -fdump-tree-inlined[-n] -fmem-report  -fpretend-float -fpro-
           file-arcs  -fsched-verbose=n -ftest-coverage  -ftime-report -g
           -glevel  -gcoff  -gdwarf  -gdwarf-1  -gdwarf-1+  -gdwarf-2 -ggdb
           -gstabs  -gstabs+  -gvms  -gxcoff  -gxcoff+ -p  -pg
           -print-file-name=library  -print-libgcc-file-name
           -print-multi-directory  -print-multi-lib -print-prog-name=program
           -print-search-dirs  -Q -save-temps  -time

       Optimization Options
           -fno-default-inline  -fno-defer-pop -fno-function-cse
           -fno-guess-branch-probability -fno-inline  -fno-math-errno
           -fno-peephole  -fno-peephole2 -funsafe-math-optimizations
           -fno-trapping-math -fomit-frame-pointer  -foptimize-register-move
           -foptimize-sibling-calls  -fprefetch-loop-arrays -freduce-all-givs
           -fregmove  -frename-registers -frerun-cse-after-loop  -fre-
           run-loop-opt -fschedule-insns  -fschedule-insns2
           -fno-sched-interblock  -fno-sched-spec -fsched-spec-load
           -fsched-spec-load-dangerous -fsingle-precision-constant  -fssa
           -fssa-ccp -fssa-dce -fstrength-reduce  -fstrict-aliasing
           -fthread-jumps -ftrapv -funroll-all-loops  -funroll-loops --param
           name=value -O  -O0  -O1  -O2  -O3  -Os

       Preprocessor Options
           -$  -Aquestion=answer  -A-question[=answer] -C  -dD  -dI  -dM  -dN
           -Dmacro[=defn]  -E  -H -idirafter dir -include file  -imacros file
           -iprefix file  -iwithprefix dir -iwithprefixbefore dir  -isystem
           dir -M  -MM  -MF  -MG  -MP  -MQ  -MT  -nostdinc  -P  -remap -tri-
           graphs  -undef  -Umacro  -Wp,option

       Assembler Option
           -Wa,option

       Linker Options
            object-file-name  -llibrary -nostartfiles  -nodefaultlibs  -nost-
           dlib -s  -static  -static-libgcc  -shared  -shared-libgcc  -sym-
           bolic -Wl,option  -Xlinker option -u symbol

       Directory Options
           -Bprefix  -Idir  -I-  -Ldir  -specs=file

       Target Options
           -b machine  -V version

       Machine Dependent Options
           M680x0 Options

           -m68000  -m68020  -m68020-40  -m68020-60  -m68030  -m68040 -m68060
           -mcpu32  -m5200  -m68881  -mbitfield  -mc68000  -mc68020 -mfpa
           -mnobitfield  -mrtd  -mshort  -msoft-float  -mpcrel -malign-int
           -mstrict-align

           M68hc1x Options

           -m6811  -m6812  -m68hc11  -m68hc12 -mauto-incdec  -mshort
           -msoft-reg-count=count

           VAX Options

           -mg  -mgnu  -munix

           SPARC Options

           -mcpu=cpu-type -mtune=cpu-type -mcmodel=code-model -m32  -m64
           -mapp-regs  -mbroken-saverestore  -mcypress -mfaster-structs
           -mflat -mfpu  -mhard-float  -mhard-quad-float -mimpure-text
           -mlive-g0  -mno-app-regs -mno-faster-structs  -mno-flat  -mno-fpu
           AMD29K Options

           -m29000  -m29050  -mbw  -mnbw  -mdw  -mndw -mlarge  -mnormal
           -msmall -mkernel-registers  -mno-reuse-arg-regs -mno-stack-check
           -mno-storem-bug -mreuse-arg-regs  -msoft-float  -mstack-check
           -mstorem-bug  -muser-registers

           ARM Options

           -mapcs-frame  -mno-apcs-frame -mapcs-26  -mapcs-32
           -mapcs-stack-check  -mno-apcs-stack-check -mapcs-float
           -mno-apcs-float -mapcs-reentrant  -mno-apcs-reentrant -msched-pro-
           log  -mno-sched-prolog -mlittle-endian  -mbig-endian  -mwords-lit-
           tle-endian -malignment-traps  -mno-alignment-traps -msoft-float
           -mhard-float  -mfpe -mthumb-interwork  -mno-thumb-interwork
           -mcpu=name  -march=name  -mfpe=name -mstructure-size-boundary=n
           -mbsd -mxopen  -mno-symrename -mabort-on-noreturn -mlong-calls
           -mno-long-calls -msingle-pic-base  -mno-single-pic-base -mpic-reg-
           ister=reg -mnop-fun-dllimport -mpoke-function-name -mthumb  -marm
           -mtpcs-frame  -mtpcs-leaf-frame -mcaller-super-interworking
           -mcallee-super-interworking

           MN10200 Options

           -mrelax

           MN10300 Options

           -mmult-bug  -mno-mult-bug -mam33  -mno-am33 -mno-crt0  -mrelax

           M32R/D Options

           -m32rx -m32r -mcode-model=model-type  -msdata=sdata-type -G num

           M88K Options

           -m88000  -m88100  -m88110  -mbig-pic -mcheck-zero-division  -mhan-
           dle-large-shift -midentify-revision  -mno-check-zero-division
           -mno-ocs-debug-info  -mno-ocs-frame-position -mno-optimize-arg-area
           -mno-serialize-volatile -mno-underscores  -mocs-debug-info
           -mocs-frame-position  -moptimize-arg-area -mserialize-volatile
           -mshort-data-num  -msvr3 -msvr4  -mtrap-large-shift
           -muse-div-instruction -mversion-03.00  -mwarn-passed-structs

           RS/6000 and PowerPC Options

           -mcpu=cpu-type -mtune=cpu-type -mpower  -mno-power  -mpower2
           -mno-power2 -mpowerpc  -mpowerpc64  -mno-powerpc -maltivec
           -mno-altivec -mpowerpc-gpopt  -mno-powerpc-gpopt -mpowerpc-gfxopt
           -mno-powerpc-gfxopt -mnew-mnemonics  -mold-mnemonics -mfull-toc
           -mminimal-toc  -mno-fp-in-toc  -mno-sum-in-toc -m64  -m32
           -mxl-call  -mno-xl-call  -mpe -msoft-float  -mhard-float  -mmulti-
           ple  -mno-multiple -mstring  -mno-string  -mupdate  -mno-update
           -mfused-madd  -mno-fused-madd  -mbit-align  -mno-bit-align
           -mstrict-align  -mno-strict-align  -mrelocatable -mno-relocatable
           -mrelocatable-lib  -mno-relocatable-lib -mtoc  -mno-toc -mlittle
           -mlittle-endian  -mbig  -mbig-endian -mcall-aix -mcall-sysv
           mum-fp-blocks  -mnohc-struct-return

           MIPS Options

           -mabicalls -march=cpu-type -mtune=cpu=type -mcpu=cpu-type -membed-
           ded-data  -muninit-const-in-rodata -membedded-pic  -mfp32  -mfp64
           -mfused-madd  -mno-fused-madd -mgas  -mgp32  -mgp64 -mgpopt
           -mhalf-pic  -mhard-float  -mint64  -mips1 -mips2  -mips3  -mips4
           -mlong64  -mlong32  -mlong-calls  -mmemcpy -mmips-as  -mmips-tfile
           -mno-abicalls -mno-embedded-data  -mno-uninit-const-in-rodata
           -mno-embedded-pic  -mno-gpopt  -mno-long-calls -mno-memcpy
           -mno-mips-tfile  -mno-rnames  -mno-stats -mrnames  -msoft-float
           -m4650  -msingle-float  -mmad -mstats  -EL  -EB  -G num  -nocpp
           -mabi=32  -mabi=n32  -mabi=64  -mabi=eabi -mfix7000  -mno-crt0
           -mflush-func=func -mno-flush-func

           i386 and x86-64 Options

           -mcpu=cpu-type  -march=cpu-type -mfpmath=unit -masm=dialect
           -mno-fancy-math-387 -mno-fp-ret-in-387  -msoft-float  -msvr3-shlib
           -mno-wide-multiply  -mrtd  -malign-double -mpreferred-stack-bound-
           ary=num -mmmx  -msse -msse2 -m3dnow -mthreads  -mno-align-stringops
           -minline-all-stringops -mpush-args  -maccumulate-outgoing-args
           -m128bit-long-double -m96bit-long-double  -mregparm=num
           -momit-leaf-frame-pointer -mno-red-zone -mcmodel=code-model -m32
           -m64

           HPPA Options

           -march=architecture-type -mbig-switch  -mdisable-fpregs  -mdis-
           able-indexing -mfast-indirect-calls  -mgas  -mjump-in-delay
           -mlong-load-store  -mno-big-switch  -mno-disable-fpregs -mno-dis-
           able-indexing  -mno-fast-indirect-calls  -mno-gas
           -mno-jump-in-delay  -mno-long-load-store -mno-portable-runtime
           -mno-soft-float -mno-space-regs  -msoft-float  -mpa-risc-1-0
           -mpa-risc-1-1  -mpa-risc-2-0  -mportable-runtime -mschedule=cpu-
           type  -mspace-regs

           Intel 960 Options

           -mcpu-type  -masm-compat  -mclean-linkage -mcode-align  -mcom-
           plex-addr  -mleaf-procedures -mic-compat  -mic2.0-compat
           -mic3.0-compat -mintel-asm  -mno-clean-linkage  -mno-code-align
           -mno-complex-addr  -mno-leaf-procedures -mno-old-align
           -mno-strict-align  -mno-tail-call -mnumerics  -mold-align
           -msoft-float  -mstrict-align -mtail-call

           DEC Alpha Options

           -mno-fp-regs  -msoft-float  -malpha-as  -mgas -mieee
           -mieee-with-inexact  -mieee-conformant -mfp-trap-mode=mode
           -mfp-rounding-mode=mode -mtrap-precision=mode  -mbuild-constants
           -mcpu=cpu-type  -mtune=cpu-type -mbwx  -mmax  -mfix  -mcix
           -mfloat-vax  -mfloat-ieee -mexplicit-relocs  -msmall-data
           -mlarge-data -mmemory-latency=time

           DEC Alpha/VMS Options
           -mrelax  -mh  -ms  -mint32  -malign-300

           SH Options

           -m1  -m2  -m3  -m3e -m4-nofpu  -m4-single-only  -m4-single  -m4
           -m5-64media -m5-64media-nofpu -m5-32media -m5-32media-nofpu
           -m5-compact -m5-compact-nofpu -mb  -ml  -mdalign  -mrelax
           -mbigtable  -mfmovd  -mhitachi  -mnomacsave -mieee  -misize  -mpad-
           struct  -mspace -mprefergot  -musermode

           System V Options

           -Qy  -Qn  -YP,paths  -Ym,dir

           ARC Options

           -EB  -EL -mmangle-cpu  -mcpu=cpu  -mtext=text-section -mdata=data-
           section  -mrodata=readonly-data-section

           TMS320C3x/C4x Options

           -mcpu=cpu  -mbig  -msmall  -mregparm  -mmemparm -mfast-fix  -mmpyi
           -mbk  -mti  -mdp-isr-reload -mrpts=count  -mrptb  -mdb
           -mloop-unsigned -mparallel-insns  -mparallel-mpy  -mpreserve-float

           V850 Options

           -mlong-calls  -mno-long-calls  -mep  -mno-ep -mprolog-function
           -mno-prolog-function  -mspace -mtda=n  -msda=n  -mzda=n -mv850
           -mbig-switch

           NS32K Options

           -m32032  -m32332  -m32532  -m32081  -m32381 -mmult-add  -mno-
           mult-add  -msoft-float  -mrtd  -mnortd -mregparam  -mnoregparam
           -msb  -mnosb -mbitfield  -mnobitfield  -mhimem  -mnohimem

           AVR Options

           -mmcu=mcu  -msize  -minit-stack=n  -mno-interrupts -mcall-prologues
           -mno-tablejump  -mtiny-stack

           MCore Options

           -mhardlit  -mno-hardlit  -mdiv  -mno-div  -mrelax-immediates
           -mno-relax-immediates  -mwide-bitfields  -mno-wide-bitfields
           -m4byte-functions  -mno-4byte-functions  -mcallgraph-data
           -mno-callgraph-data  -mslow-bytes  -mno-slow-bytes  -mno-lsim
           -mlittle-endian  -mbig-endian  -m210  -m340  -mstack-increment

           MMIX Options

           -mlibfuncs -mno-libfuncs -mepsilon -mno-epsilon -mabi=gnu
           -mabi=mmixware -mzero-extend -mknuthdiv -mtoplevel-symbols -melf
           -mbranch-predict -mno-branch-predict -mbase-addresses
           -mno-base-addresses


           -mextmem  -mextmemory  -monchip  -mno-asm-optimize -masm-optimize
           -mbranch-cost=n -mcond-exec=n

           S/390 and zSeries Options

           -mhard-float  -msoft-float  -mbackchain  -mno-backchain
           -msmall-exec  -mno-small-exec  -mmvcle -mno-mvcle -m64 -m31 -mdebug
           -mno-debug

           CRIS Options

           -mcpu=cpu -march=cpu -mtune=cpu -mmax-stack-frame=n -melinux-stack-
           size=n -metrax4 -metrax100 -mpdebug -mcc-init -mno-side-effects
           -mstack-align -mdata-align -mconst-align -m32-bit -m16-bit -m8-bit
           -mno-prologue-epilogue -mno-gotplt -melf -maout -melinux -mlinux
           -sim -sim2

           PDP-11 Options

           -mfpu  -msoft-float  -mac0  -mno-ac0  -m40  -m45  -m10 -mbcopy
           -mbcopy-builtin  -mint32  -mno-int16 -mint16  -mno-int32  -mfloat32
           -mno-float64 -mfloat64  -mno-float32  -mabshi  -mno-abshi
           -mbranch-expensive  -mbranch-cheap -msplit  -mno-split  -munix-asm
           -mdec-asm

           Xstormy16 Options

           -msim

           Xtensa Options

           -mbig-endian -mlittle-endian -mdensity -mno-density -mmac16
           -mno-mac16 -mmul16 -mno-mul16 -mmul32 -mno-mul32 -mnsa -mno-nsa
           -mminmax -mno-minmax -msext -mno-sext -mbooleans -mno-booleans
           -mhard-float -msoft-float -mfused-madd -mno-fused-madd -mserial-
           ize-volatile -mno-serialize-volatile -mtext-section-literals
           -mno-text-section-literals -mtarget-align -mno-target-align -mlong-
           calls -mno-longcalls

       Code Generation Options
           -fcall-saved-reg  -fcall-used-reg -ffixed-reg -fexceptions
           -fnon-call-exceptions  -funwind-tables -fasynchronous-unwind-tables
           -finhibit-size-directive  -finstrument-functions -fno-common
           -fno-ident  -fno-gnu-linker -fpcc-struct-return  -fpic  -fPIC
           -freg-struct-return  -fshared-data  -fshort-enums -fshort-double
           -fshort-wchar -fvolatile -fvolatile-global  -fvolatile-static
           -fverbose-asm  -fpack-struct  -fstack-check -fstack-limit-regis-
           ter=reg  -fstack-limit-symbol=sym -fargument-alias  -fargu-
           ment-noalias -fargument-noalias-global  -fleading-underscore
           -ftls-model=model

       Options Controlling the Kind of Output

       Compilation can involve up to four stages: preprocessing, compilation
       proper, assembly and linking, always in that order.  The first three
       stages apply to an individual source file, and end by producing an
       file.i
           C source code which should not be preprocessed.

       file.ii
           C++ source code which should not be preprocessed.

       file.m
           Objective-C source code.  Note that you must link with the library
           libobjc.a to make an Objective-C program work.

       file.mi
           Objective-C source code which should not be preprocessed.

       file.h
           C header file (not to be compiled or linked).

       file.cc
       file.cp
       file.cxx
       file.cpp
       file.c++
       file.C
           C++ source code which must be preprocessed.  Note that in .cxx, the
           last two letters must both be literally x.  Likewise, .C refers to
           a literal capital C.

       file.f
       file.for
       file.FOR
           Fortran source code which should not be preprocessed.

       file.F
       file.fpp
       file.FPP
           Fortran source code which must be preprocessed (with the tradi-
           tional preprocessor).

       file.r
           Fortran source code which must be preprocessed with a RATFOR pre-
           processor (not included with GCC).

       file.ads
           Ada source code file which contains a library unit declaration (a
           declaration of a package, subprogram, or generic, or a generic
           instantiation), or a library unit renaming declaration (a package,
           generic, or subprogram renaming declaration).  Such files are also
           called specs.

       file.adb
           Ada source code file containing a library unit body (a subprogram
           or package body).  Such files are also called bodies.

       file.s
           Assembler code.

       file.S
           Assembler code which must be preprocessed.
           (rather than letting the compiler choose a default based on the
           file name suffix).  This option applies to all following input
           files until the next -x option.  Possible values for language are:

                   c  c-header  cpp-output
                   c++  c++-cpp-output
                   objective-c  objc-cpp-output
                   assembler  assembler-with-cpp
                   ada
                   f77  f77-cpp-input  ratfor
                   java

       -x none
           Turn off any specification of a language, so that subsequent files
           are handled according to their file name suffixes (as they are if
           -x has not been used at all).

       -pass-exit-codes
           Normally the gcc program will exit with the code of 1 if any phase
           of the compiler returns a non-success return code.  If you specify
           -pass-exit-codes, the gcc program will instead return with numeri-
           cally highest error produced by any phase that returned an error
           indication.

       If you only want some of the stages of compilation, you can use -x (or
       filename suffixes) to tell gcc where to start, and one of the options
       -c, -S, or -E to say where gcc is to stop.  Note that some combinations
       (for example, -x cpp-output -E) instruct gcc to do nothing at all.

       -c  Compile or assemble the source files, but do not link.  The linking
           stage simply is not done.  The ultimate output is in the form of an
           object file for each source file.

           By default, the object file name for a source file is made by
           replacing the suffix .c, .i, .s, etc., with .o.

           Unrecognized input files, not requiring compilation or assembly,
           are ignored.

       -S  Stop after the stage of compilation proper; do not assemble.  The
           output is in the form of an assembler code file for each non-assem-
           bler input file specified.

           By default, the assembler file name for a source file is made by
           replacing the suffix .c, .i, etc., with .s.

           Input files that don't require compilation are ignored.

       -E  Stop after the preprocessing stage; do not run the compiler proper.
           The output is in the form of preprocessed source code, which is
           sent to the standard output.

           Input files which don't require preprocessing are ignored.

       -o file
           Place output in file file.  This applies regardless to whatever
           sort of output is being produced, whether it be an executable file,

       -v  Print (on standard error output) the commands executed to run the
           stages of compilation.  Also print the version number of the com-
           piler driver program and of the preprocessor and the compiler
           proper.

       -###
           Like -v except the commands are not executed and all command argu-
           ments are quoted.  This is useful for shell scripts to capture the
           driver-generated command lines.

       -pipe
           Use pipes rather than temporary files for communication between the
           various stages of compilation.  This fails to work on some systems
           where the assembler is unable to read from a pipe; but the GNU
           assembler has no trouble.

       --help
           Print (on the standard output) a description of the command line
           options understood by gcc.  If the -v option is also specified then
           --help will also be passed on to the various processes invoked by
           gcc, so that they can display the command line options they accept.
           If the -W option is also specified then command line options which
           have no documentation associated with them will also be displayed.

       --target-help
           Print (on the standard output) a description of target specific
           command line options for each tool.

       --version
           Display the version number and copyrights of the invoked GCC.

       Compiling C++ Programs

       C++ source files conventionally use one of the suffixes .C, .cc, .cpp,
       .c++, .cp, or .cxx; preprocessed C++ files use the suffix .ii.  GCC
       recognizes files with these names and compiles them as C++ programs
       even if you call the compiler the same way as for compiling C programs
       (usually with the name gcc).

       However, C++ programs often require class libraries as well as a com-
       piler that understands the C++ language---and under some circumstances,
       you might want to compile programs from standard input, or otherwise
       without a suffix that flags them as C++ programs.  g++ is a program
       that calls GCC with the default language set to C++, and automatically
       specifies linking against the C++ library.  On many systems, g++ is
       also installed with the name c++.

       When you compile C++ programs, you may specify many of the same com-
       mand-line options that you use for compiling programs in any language;
       or command-line options meaningful for C and related languages; or
       options that are meaningful only for C++ programs.

       Options Controlling C Dialect

       The following options control the dialect of C (or languages derived
       from C, such as C++ and Objective-C) that the compiler accepts:
           you are using.  It also enables the undesirable and rarely used ISO
           trigraph feature.  For the C compiler, it disables recognition of
           C++ style // comments as well as the "inline" keyword.

           The alternate keywords "__asm__", "__extension__", "__inline__" and
           "__typeof__" continue to work despite -ansi.  You would not want to
           use them in an ISO C program, of course, but it is useful to put
           them in header files that might be included in compilations done
           with -ansi.  Alternate predefined macros such as "__unix__" and
           "__vax__" are also available, with or without -ansi.

           The -ansi option does not cause non-ISO programs to be rejected
           gratuitously.  For that, -pedantic is required in addition to
           -ansi.

           The macro "__STRICT_ANSI__" is predefined when the -ansi option is
           used.  Some header files may notice this macro and refrain from
           declaring certain functions or defining certain macros that the ISO
           standard doesn't call for; this is to avoid interfering with any
           programs that might use these names for other things.

           Functions which would normally be built in but do not have seman-
           tics defined by ISO C (such as "alloca" and "ffs") are not built-in
           functions with -ansi is used.

       -std=
           Determine the language standard.  This option is currently only
           supported when compiling C.  A value for this option must be pro-
           vided; possible values are

           c89
           iso9899:1990
               ISO C89 (same as -ansi).

           iso9899:199409
               ISO C89 as modified in amendment 1.

           c99
           c9x
           iso9899:1999
           iso9899:199x
               ISO C99.  Note that this standard is not yet fully supported;
               see <http://gcc.gnu.org/gcc-3.1/c99status.html> for more infor-
               mation.  The names c9x and iso9899:199x are deprecated.

           gnu89
               Default, ISO C89 plus GNU extensions (including some C99 fea-
               tures).

           gnu99
           gnu9x
               ISO C99 plus GNU extensions.  When ISO C99 is fully implemented
               in GCC, this will become the default.  The name gnu9x is depre-
               cated.

           Even when this option is not specified, you can still use some of
           the features of newer standards in so far as they do not conflict
           Output to the given filename prototyped declarations for all func-
           tions declared and/or defined in a translation unit, including
           those in header files.  This option is silently ignored in any lan-
           guage other than C.

           Besides declarations, the file indicates, in comments, the origin
           of each declaration (source file and line), whether the declaration
           was implicit, prototyped or unprototyped (I, N for new or O for
           old, respectively, in the first character after the line number and
           the colon), and whether it came from a declaration or a definition
           (C or F, respectively, in the following character).  In the case of
           function definitions, a K&R-style list of arguments followed by
           their declarations is also provided, inside comments, after the
           declaration.

       -fno-asm
           Do not recognize "asm", "inline" or "typeof" as a keyword, so that
           code can use these words as identifiers.  You can use the keywords
           "__asm__", "__inline__" and "__typeof__" instead.  -ansi implies
           -fno-asm.

           In C++, this switch only affects the "typeof" keyword, since "asm"
           and "inline" are standard keywords.  You may want to use the
           -fno-gnu-keywords flag instead, which has the same effect.  In C99
           mode (-std=c99 or -std=gnu99), this switch only affects the "asm"
           and "typeof" keywords, since "inline" is a standard keyword in ISO
           C99.

       -fno-builtin
       -fno-builtin-function (C and Objective-C only)
           Don't recognize built-in functions that do not begin with
           __builtin_ as prefix.

           GCC normally generates special code to handle certain built-in
           functions more efficiently; for instance, calls to "alloca" may
           become single instructions that adjust the stack directly, and
           calls to "memcpy" may become inline copy loops.  The resulting code
           is often both smaller and faster, but since the function calls no
           longer appear as such, you cannot set a breakpoint on those calls,
           nor can you change the behavior of the functions by linking with a
           different library.

           In C++, -fno-builtin is always in effect.  The -fbuiltin option has
           no effect.  Therefore, in C++, the only way to get the optimization
           benefits of built-in functions is to call the function using the
           __builtin_ prefix.  The GNU C++ Standard Library uses built-in
           functions to implement many functions (like "std::strchr"), so that
           you automatically get efficient code.

           With the -fno-builtin-function option, not available when compiling
           C++, only the built-in function function is disabled.  function
           must not begin with __builtin_.  If a function is named this is not
           built-in in this version of GCC, this option is ignored.  There is
           no corresponding -fbuiltin-function option; if you wish to enable
           built-in functions selectively when using -fno-builtin or -ffree-
           standing, you may define macros such as:


       -ffreestanding
           Assert that compilation takes place in a freestanding environment.
           This implies -fno-builtin.  A freestanding environment is one in
           which the standard library may not exist, and program startup may
           not necessarily be at "main".  The most obvious example is an OS
           kernel.  This is equivalent to -fno-hosted.

       -trigraphs
           Support ISO C trigraphs.  The -ansi option (and -std options for
           strict ISO C conformance) implies -trigraphs.

       -no-integrated-cpp
           Invoke the external cpp during compilation.  The default is to use
           the integrated cpp (internal cpp).  This option also allows a user-
           supplied cpp via the -B option.  This flag is applicable in both C
           and C++ modes.

           We do not guarantee to retain this option in future, and we may
           change its semantics.

       -traditional
           Attempt to support some aspects of traditional C compilers.
           Specifically:

              All "extern" declarations take effect globally even if they are
               written inside of a function definition.  This includes
               implicit declarations of functions.

              The newer keywords "typeof", "inline", "signed", "const" and
               "volatile" are not recognized.  (You can still use the alterna-
               tive keywords such as "__typeof__", "__inline__", and so on.)

              Comparisons between pointers and integers are always allowed.

              Integer types "unsigned short" and "unsigned char" promote to
               "unsigned int".

              Out-of-range floating point literals are not an error.

              Certain constructs which ISO regards as a single invalid pre-
               processing number, such as 0xe-0xd, are treated as expressions
               instead.

              String ``constants'' are not necessarily constant; they are
               stored in writable space, and identical looking constants are
               allocated separately.  (This is the same as the effect of
               -fwritable-strings.)

              All automatic variables not declared "register" are preserved
               by "longjmp".  Ordinarily, GNU C follows ISO C: automatic vari-
               ables not declared "volatile" may be clobbered.

              The character escape sequences \x and \a evaluate as the lit-
               eral characters x and a respectively.  Without -traditional, \x
               is a prefix for the hexadecimal representation of a character,
               and \a produces a bell.

           with ISO C header files and you cannot use -traditional on such
           systems to compile files that include any system headers.

           The -traditional option also enables -traditional-cpp.

       -traditional-cpp
           Attempt to support some aspects of traditional C preprocessors.
           See the GNU CPP manual for details.

       -fcond-mismatch
           Allow conditional expressions with mismatched types in the second
           and third arguments.  The value of such an expression is void.
           This option is not supported for C++.

       -funsigned-char
           Let the type "char" be unsigned, like "unsigned char".

           Each kind of machine has a default for what "char" should be.  It
           is either like "unsigned char" by default or like "signed char" by
           default.

           Ideally, a portable program should always use "signed char" or
           "unsigned char" when it depends on the signedness of an object.
           But many programs have been written to use plain "char" and expect
           it to be signed, or expect it to be unsigned, depending on the
           machines they were written for.  This option, and its inverse, let
           you make such a program work with the opposite default.

           The type "char" is always a distinct type from each of "signed
           char" or "unsigned char", even though its behavior is always just
           like one of those two.

       -fsigned-char
           Let the type "char" be signed, like "signed char".

           Note that this is equivalent to -fno-unsigned-char, which is the
           negative form of -funsigned-char.  Likewise, the option
           -fno-signed-char is equivalent to -funsigned-char.

       -fsigned-bitfields
       -funsigned-bitfields
       -fno-signed-bitfields
       -fno-unsigned-bitfields
           These options control whether a bit-field is signed or unsigned,
           when the declaration does not use either "signed" or "unsigned".
           By default, such a bit-field is signed, because this is consistent:
           the basic integer types such as "int" are signed types.

           However, when -traditional is used, bit-fields are all unsigned no
           matter what.

       -fwritable-strings
           Store string constants in the writable data segment and don't
           uniquize them.  This is for compatibility with old programs which
           assume they can write into string constants.  The option -tradi-
           tional also has this effect.

           tecture for which you are compiling, single precision may be faster
           than double precision.   If you must use -traditional, but want to
           use single precision operations when the operands are single preci-
           sion, use this option.   This option has no effect when compiling
           with ISO or GNU C conventions (the default).

       Options Controlling C++ Dialect

       This section describes the command-line options that are only meaning-
       ful for C++ programs; but you can also use most of the GNU compiler
       options regardless of what language your program is in.  For example,
       you might compile a file "firstClass.C" like this:

               g++ -g -frepo -O -c firstClass.C

       In this example, only -frepo is an option meant only for C++ programs;
       you can use the other options with any language supported by GCC.

       Here is a list of options that are only for compiling C++ programs:

       -fno-access-control
           Turn off all access checking.  This switch is mainly useful for
           working around bugs in the access control code.

       -fcheck-new
           Check that the pointer returned by "operator new" is non-null
           before attempting to modify the storage allocated.  The current
           Working Paper requires that "operator new" never return a null
           pointer, so this check is normally unnecessary.

           An alternative to using this option is to specify that your "opera-
           tor new" does not throw any exceptions; if you declare it tthhrrooww(()),
           G++ will check the return value.  See also new (nothrow).

       -fconserve-space
           Put uninitialized or runtime-initialized global variables into the
           common segment, as C does.  This saves space in the executable at
           the cost of not diagnosing duplicate definitions.  If you compile
           with this flag and your program mysteriously crashes after "main()"
           has completed, you may have an object that is being destroyed twice
           because two definitions were merged.

           This option is no longer useful on most targets, now that support
           has been added for putting variables into BSS without making them
           common.

       -fno-const-strings
           Give string constants type "char *" instead of type "const char *".
           By default, G++ uses type "const char *" as required by the stan-
           dard.  Even if you use -fno-const-strings, you cannot actually mod-
           ify the value of a string constant, unless you also use
           -fwritable-strings.

           This option might be removed in a future release of G++.  For maxi-
           mum portability, you should structure your code so that it works
           with string constants that have type "const char *".

           rary which is only used to initialize another object of the same
           type.  Specifying this option disables that optimization, and
           forces G++ to call the copy constructor in all cases.

       -fno-enforce-eh-specs
           Don't check for violation of exception specifications at runtime.
           This option violates the C++ standard, but may be useful for reduc-
           ing code size in production builds, much like defining NDEBUG.  The
           compiler will still optimize based on the exception specifications.

       -fexternal-templates
           Cause #pragma interface and implementation to apply to template
           instantiation; template instances are emitted or not according to
           the location of the template definition.

           This option is deprecated.

       -falt-external-templates
           Similar to -fexternal-templates, but template instances are emitted
           or not according to the place where they are first instantiated.

           This option is deprecated.

       -ffor-scope
       -fno-for-scope
           If -ffor-scope is specified, the scope of variables declared in a
           for-init-statement is limited to the for loop itself, as specified
           by the C++ standard.  If -fno-for-scope is specified, the scope of
           variables declared in a for-init-statement extends to the end of
           the enclosing scope, as was the case in old versions of G++, and
           other (traditional) implementations of C++.

           The default if neither flag is given to follow the standard, but to
           allow and give a warning for old-style code that would otherwise be
           invalid, or have different behavior.

       -fno-gnu-keywords
           Do not recognize "typeof" as a keyword, so that code can use this
           word as an identifier.  You can use the keyword "__typeof__"
           instead.  -ansi implies -fno-gnu-keywords.

       -fno-implicit-templates
           Never emit code for non-inline templates which are instantiated
           implicitly (i.e. by use); only emit code for explicit instantia-
           tions.

       -fno-implicit-inline-templates
           Don't emit code for implicit instantiations of inline templates,
           either.  The default is to handle inlines differently so that com-
           piles with and without optimization will need the same set of
           explicit instantiations.

       -fno-implement-inlines
           To save space, do not emit out-of-line copies of inline functions
           controlled by #pragma implementation.  This will cause linker
           errors if these functions are not inlined everywhere they are
           called.
           "bzero", "conjf", and other related functions.

       -fno-operator-names
           Do not treat the operator name keywords "and", "bitand", "bitor",
           "compl", "not", "or" and "xor" as synonyms as keywords.

       -fno-optional-diags
           Disable diagnostics that the standard says a compiler does not need
           to issue.  Currently, the only such diagnostic issued by G++ is the
           one for a name having multiple meanings within a class.

       -fpermissive
           Downgrade messages about nonconformant code from errors to warn-
           ings.  By default, G++ effectively sets -pedantic-errors without
           -pedantic; this option reverses that.  This behavior and this
           option are superseded by -pedantic, which works as it does for GNU
           C.

       -frepo
           Enable automatic template instantiation at link time.  This option
           also implies -fno-implicit-templates.

       -fno-rtti
           Disable generation of information about every class with virtual
           functions for use by the C++ runtime type identification features
           (dynamic_cast and typeid).  If you don't use those parts of the
           language, you can save some space by using this flag.  Note that
           exception handling uses the same information, but it will generate
           it as needed.

       -fstats
           Emit statistics about front-end processing at the end of the compi-
           lation.  This information is generally only useful to the G++
           development team.

       -ftemplate-depth-n
           Set the maximum instantiation depth for template classes to n.  A
           limit on the template instantiation depth is needed to detect end-
           less recursions during template class instantiation.  ANSI/ISO C++
           conforming programs must not rely on a maximum depth greater than
           17.

       -fuse-cxa-atexit
           Register destructors for objects with static storage duration with
           the "__cxa_atexit" function rather than the "atexit" function.
           This option is required for fully standards-compliant handling of
           static destructors, but will only work if your C library supports
           "__cxa_atexit".

       -fvtable-gc
           Emit special relocations for vtables and virtual function refer-
           ences so that the linker can identify unused virtual functions and
           zero out vtable slots that refer to them.  This is most useful with
           -ffunction-sections and -Wl,--gc-sections, in order to also discard
           the functions themselves.

           This optimization requires GNU as and GNU ld.  Not all systems sup-

       -nostdinc++
           Do not search for header files in the standard directories specific
           to C++, but do still search the other standard directories.  (This
           option is used when building the C++ library.)

       In addition, these optimization, warning, and code generation options
       have meanings only for C++ programs:

       -fno-default-inline
           Do not assume inline for functions defined inside a class scope.
             Note that these functions will have linkage like inline func-
           tions; they just won't be inlined by default.

       -Wabi (C++ only)
           Warn when G++ generates code that is probably not compatible with
           the vendor-neutral C++ ABI.  Although an effort has been made to
           warn about all such cases, there are probably some cases that are
           not warned about, even though G++ is generating incompatible code.
           There may also be cases where warnings are emitted even though the
           code that is generated will be compatible.

           You should rewrite your code to avoid these warnings if you are
           concerned about the fact that code generated by G++ may not be
           binary compatible with code generated by other compilers.

           The known incompatibilites at this point include:

              Incorrect handling of tail-padding for bit-fields.  G++ may
               attempt to pack data into the same byte as a base class.  For
               example:

                       struct A { virtual void f(); int f1 : 1; };
                       struct B : public A { int f2 : 1; };

               In this case, G++ will place "B::f2" into the same byte
               as"A::f1"; other compilers will not.  You can avoid this prob-
               lem by explicitly padding "A" so that its size is a multiple of
               the byte size on your platform; that will cause G++ and other
               compilers to layout "B" identically.

              Incorrect handling of tail-padding for virtual bases.  G++ does
               not use tail padding when laying out virtual bases.  For exam-
               ple:

                       struct A { virtual void f(); char c1; };
                       struct B { B(); char c2; };
                       struct C : public A, public virtual B {};

               In this case, G++ will not place "B" into the tail-padding for
               "A"; other compilers will.  You can avoid this problem by
               explicitly padding "A" so that its size is a multiple of its
               alignment (ignoring virtual base classes); that will cause G++
               and other compilers to layout "C" identically.

       -Wctor-dtor-privacy (C++ only)
           Warn when a class seems unusable, because all the constructors or
           destructors in a class are private and the class has no friends or
           not match the order in which they must be executed.  For instance:

                   struct A {
                     int i;
                     int j;
                     A(): j (0), i (1) { }
                   };

           Here the compiler will warn that the member initializers for i and
           j will be rearranged to match the declaration order of the members.

       The following -W... options are not affected by -Wall.

       -Weffc++ (C++ only)
           Warn about violations of the following style guidelines from Scott
           Meyers' Effective C++ book:

              Item 11:  Define a copy constructor and an assignment operator
               for classes with dynamically allocated memory.

              Item 12:  Prefer initialization to assignment in constructors.

              Item 14:  Make destructors virtual in base classes.

              Item 15:  Have "operator=" return a reference to *this.

              Item 23:  Don't try to return a reference when you must return
               an object.

           and about violations of the following style guidelines from Scott
           Meyers' More Effective C++ book:

              Item 6:  Distinguish between prefix and postfix forms of incre-
               ment and decrement operators.

              Item 7:  Never overload "&&", "||", or ",".

           If you use this option, you should be aware that the standard
           library headers do not obey all of these guidelines; you can use
           grep -v to filter out those warnings.

       -Wno-deprecated (C++ only)
           Do not warn about usage of deprecated features.

       -Wno-non-template-friend (C++ only)
           Disable warnings when non-templatized friend functions are declared
           within a template.  With the advent of explicit template specifica-
           tion support in G++, if the name of the friend is an unqualified-id
           (i.e., friend foo(int)), the C++ language specification demands
           that the friend declare or define an ordinary, nontemplate func-
           tion.  (Section 14.5.3).  Before G++ implemented explicit specifi-
           cation, unqualified-ids could be interpreted as a particular spe-
           cialization of a templatized function.  Because this non-conforming
           behavior is no longer the default behavior for G++, -Wnon-tem-
           plate-friend allows the compiler to check existing code for poten-
           tial trouble spots, and is on by default.  This new compiler behav-
           ior can be turned off with -Wno-non-template-friend which keeps the
           Warn when a function declaration hides virtual functions from a
           base class.  For example, in:

                   struct A {
                     virtual void f();
                   };

                   struct B: public A {
                     void f(int);
                   };

           the "A" class version of "f" is hidden in "B", and code like this:

                   B* b;
                   b->f();

           will fail to compile.

       -Wno-pmf-conversions (C++ only)
           Disable the diagnostic for converting a bound pointer to member
           function to a plain pointer.

       -Wsign-promo (C++ only)
           Warn when overload resolution chooses a promotion from unsigned or
           enumeral type to a signed type over a conversion to an unsigned
           type of the same size.  Previous versions of G++ would try to pre-
           serve unsignedness, but the standard mandates the current behavior.

       -Wsynth (C++ only)
           Warn when G++'s synthesis behavior does not match that of cfront.
           For instance:

                   struct A {
                     operator int ();
                     A& operator = (int);
                   };

                   main ()
                   {
                     A a,b;
                     a = b;
                   }

           In this example, G++ will synthesize a default A& operator = (const
           A&);, while cfront will use the user-defined operator =.

       Options Controlling Objective-C Dialect

       This section describes the command-line options that are only meaning-
       ful for Objective-C programs; but you can also use most of the GNU com-
       piler options regardless of what language your program is in.  For
       example, you might compile a file "some_class.m" like this:

               gcc -g -fgnu-runtime -O -c some_class.m

       In this example, only -fgnu-runtime is an option meant only for Objec-
       tive-C programs; you can use the other options with any language sup-

       -fgnu-runtime
           Generate object code compatible with the standard GNU Objective-C
           runtime.  This is the default for most types of systems.

       -fnext-runtime
           Generate output compatible with the NeXT runtime.  This is the
           default for NeXT-based systems, including Darwin and Mac OS X.

       -gen-decls
           Dump interface declarations for all classes seen in the source file
           to a file named sourcename.decl.

       -Wno-protocol
           Do not warn if methods required by a protocol are not implemented
           in the class adopting it.

       -Wselector
           Warn if a selector has multiple methods of different types defined.

       Options to Control Diagnostic Messages Formatting

       Traditionally, diagnostic messages have been formatted irrespective of
       the output device's aspect (e.g. its width, ...).  The options
       described below can be used to control the diagnostic messages format-
       ting algorithm, e.g. how many characters per line, how often source
       location information should be reported.  Right now, only the C++ front
       end can honor these options.  However it is expected, in the near
       future, that the remaining front ends would be able to digest them cor-
       rectly.

       -fmessage-length=n
           Try to format error messages so that they fit on lines of about n
           characters.  The default is 72 characters for g++ and 0 for the
           rest of the front ends supported by GCC.  If n is zero, then no
           line-wrapping will be done; each error message will appear on a
           single line.

       -fdiagnostics-show-location=once
           Only meaningful in line-wrapping mode.  Instructs the diagnostic
           messages reporter to emit once source location information; that
           is, in case the message is too long to fit on a single physical
           line and has to be wrapped, the source location won't be emitted
           (as prefix) again, over and over, in subsequent continuation lines.
           This is the default behavior.

       -fdiagnostics-show-location=every-line
           Only meaningful in line-wrapping mode.  Instructs the diagnostic
           messages reporter to emit the same source location information (as
           prefix) for physical lines that result from the process of breaking
           a message which is too long to fit on a single line.

       Options to Request or Suppress Warnings

       Warnings are diagnostic messages that report constructions which are
       not inherently erroneous but which are risky or suggest there may have
       been an error.
       Dialect Options} and @ref{Objective-C Dialect Options}.

       -fsyntax-only
           Check the code for syntax errors, but don't do anything beyond
           that.

       -pedantic
           Issue all the warnings demanded by strict ISO C and ISO C++; reject
           all programs that use forbidden extensions, and some other programs
           that do not follow ISO C and ISO C++.  For ISO C, follows the ver-
           sion of the ISO C standard specified by any -std option used.

           Valid ISO C and ISO C++ programs should compile properly with or
           without this option (though a rare few will require -ansi or a -std
           option specifying the required version of ISO C).  However, without
           this option, certain GNU extensions and traditional C and C++ fea-
           tures are supported as well.  With this option, they are rejected.

           -pedantic does not cause warning messages for use of the alternate
           keywords whose names begin and end with __.  Pedantic warnings are
           also disabled in the expression that follows "__extension__".  How-
           ever, only system header files should use these escape routes;
           application programs should avoid them.

           Some users try to use -pedantic to check programs for strict ISO C
           conformance.  They soon find that it does not do quite what they
           want: it finds some non-ISO practices, but not all---only those for
           which ISO C requires a diagnostic, and some others for which diag-
           nostics have been added.

           A feature to report any failure to conform to ISO C might be useful
           in some instances, but would require considerable additional work
           and would be quite different from -pedantic.  We don't have plans
           to support such a feature in the near future.

           Where the standard specified with -std represents a GNU extended
           dialect of C, such as gnu89 or gnu99, there is a corresponding base
           standard, the version of ISO C on which the GNU extended dialect is
           based.  Warnings from -pedantic are given where they are required
           by the base standard.  (It would not make sense for such warnings
           to be given only for features not in the specified GNU C dialect,
           since by definition the GNU dialects of C include all features the
           compiler supports with the given option, and there would be nothing
           to warn about.)

       -pedantic-errors
           Like -pedantic, except that errors are produced rather than warn-
           ings.

       -w  Inhibit all warning messages.

       -Wno-import
           Inhibit warning messages about the use of #import.

       -Wchar-subscripts
           Warn if an array subscript has type "char".  This is a common cause
           of error, as programmers often forget that this type is signed on
           specified, and that the conversions specified in the format string
           make sense.  This includes standard functions, and others specified
           by format attributes, in the "printf", "scanf", "strftime" and
           "strfmon" (an X/Open extension, not in the C standard) families.

           The formats are checked against the format features supported by
           GNU libc version 2.2.  These include all ISO C89 and C99 features,
           as well as features from the Single Unix Specification and some BSD
           and GNU extensions.  Other library implementations may not support
           all these features; GCC does not support warning about features
           that go beyond a particular library's limitations.  However, if
           -pedantic is used with -Wformat, warnings will be given about for-
           mat features not in the selected standard version (but not for
           "strfmon" formats, since those are not in any version of the C
           standard).

           -Wformat is included in -Wall.  For more control over some aspects
           of format checking, the options -Wno-format-y2k, -Wno-for-
           mat-extra-args, -Wformat-nonliteral, -Wformat-security and -Wfor-
           mat=2 are available, but are not included in -Wall.

       -Wno-format-y2k
           If -Wformat is specified, do not warn about "strftime" formats
           which may yield only a two-digit year.

       -Wno-format-extra-args
           If -Wformat is specified, do not warn about excess arguments to a
           "printf" or "scanf" format function.  The C standard specifies that
           such arguments are ignored.

           Where the unused arguments lie between used arguments that are
           specified with $ operand number specifications, normally warnings
           are still given, since the implementation could not know what type
           to pass to "va_arg" to skip the unused arguments.  However, in the
           case of "scanf" formats, this option will suppress the warning if
           the unused arguments are all pointers, since the Single Unix Speci-
           fication says that such unused arguments are allowed.

       -Wformat-nonliteral
           If -Wformat is specified, also warn if the format string is not a
           string literal and so cannot be checked, unless the format function
           takes its format arguments as a "va_list".

       -Wformat-security
           If -Wformat is specified, also warn about uses of format functions
           that represent possible security problems.  At present, this warns
           about calls to "printf" and "scanf" functions where the format
           string is not a string literal and there are no format arguments,
           as in "printf (foo);".  This may be a security hole if the format
           string came from untrusted input and contains %n.  (This is cur-
           rently a subset of what -Wformat-nonliteral warns about, but in
           future warnings may be added to -Wformat-security that are not
           included in -Wformat-nonliteral.)

       -Wformat=2
           Enable -Wformat plus format checks not included in -Wformat.  Cur-
           rently equivalent to -Wformat -Wformat-nonliteral

       -Wimplicit
           Same as -Wimplicit-int and -Wimplicit-function-declaration.

       -Wmain
           Warn if the type of main is suspicious.  main should be a function
           with external linkage, returning int, taking either zero arguments,
           two, or three arguments of appropriate types.

       -Wmissing-braces
           Warn if an aggregate or union initializer is not fully bracketed.
           In the following example, the initializer for a is not fully brack-
           eted, but that for b is fully bracketed.

                   int a[2][2] = { 0, 1, 2, 3 };
                   int b[2][2] = { { 0, 1 }, { 2, 3 } };

       -Wparentheses
           Warn if parentheses are omitted in certain contexts, such as when
           there is an assignment in a context where a truth value is
           expected, or when operators are nested whose precedence people
           often get confused about.

           Also warn about constructions where there may be confusion to which
           "if" statement an "else" branch belongs.  Here is an example of
           such a case:

                   {
                     if (a)
                       if (b)
                         foo ();
                     else
                       bar ();
                   }

           In C, every "else" branch belongs to the innermost possible "if"
           statement, which in this example is "if (b)".  This is often not
           what the programmer expected, as illustrated in the above example
           by indentation the programmer chose.  When there is the potential
           for this confusion, GCC will issue a warning when this flag is
           specified.  To eliminate the warning, add explicit braces around
           the innermost "if" statement so there is no way the "else" could
           belong to the enclosing "if".  The resulting code would look like
           this:

                   {
                     if (a)
                       {
                         if (b)
                           foo ();
                         else
                           bar ();
                       }
                   }

       -Wsequence-point
           Warn about code that may have undefined semantics because of viola-
           before a function is called (but after the evaluation of its argu-
           ments and the expression denoting the called function), and in cer-
           tain other places.  Other than as expressed by the sequence point
           rules, the order of evaluation of subexpressions of an expression
           is not specified.  All these rules describe only a partial order
           rather than a total order, since, for example, if two functions are
           called within one expression with no sequence point between them,
           the order in which the functions are called is not specified.  How-
           ever, the standards committee have ruled that function calls do not
           overlap.

           It is not specified when between sequence points modifications to
           the values of objects take effect.  Programs whose behavior depends
           on this have undefined behavior; the C standard specifies that
           ``Between the previous and next sequence point an object shall have
           its stored value modified at most once by the evaluation of an
           expression.  Furthermore, the prior value shall be read only to
           determine the value to be stored.''.  If a program breaks these
           rules, the results on any particular implementation are entirely
           unpredictable.

           Examples of code with undefined behavior are "a = a++;", "a[n] =
           b[n++]" and "a[i++] = i;".  Some more complicated cases are not
           diagnosed by this option, and it may give an occasional false posi-
           tive result, but in general it has been found fairly effective at
           detecting this sort of problem in programs.

           The present implementation of this option only works for C pro-
           grams.  A future implementation may also work for C++ programs.

           The C standard is worded confusingly, therefore there is some
           debate over the precise meaning of the sequence point rules in sub-
           tle cases.  Links to discussions of the problem, including proposed
           formal definitions, may be found on our readings page, at
           <http://gcc.gnu.org/readings.html>.

       -Wreturn-type
           Warn whenever a function is defined with a return-type that
           defaults to "int".  Also warn about any "return" statement with no
           return-value in a function whose return-type is not "void".

           For C++, a function without return type always produces a diagnos-
           tic message, even when -Wno-return-type is specified.  The only
           exceptions are main and functions defined in system headers.

       -Wswitch
           Warn whenever a "switch" statement has an index of enumeral type
           and lacks a "case" for one or more of the named codes of that enu-
           meration.  (The presence of a "default" label prevents this warn-
           ing.)  "case" labels outside the enumeration range also provoke
           warnings when this option is used.

       -Wtrigraphs
           Warn if any trigraphs are encountered that might change the meaning
           of the program (trigraphs within comments are not warned about).

       -Wunused-function
           Warn whenever a function parameter is unused aside from its decla-
           ration.

           To suppress this warning use the unused attribute.

       -Wunused-variable
           Warn whenever a local variable or non-constant static variable is
           unused aside from its declaration

           To suppress this warning use the unused attribute.

       -Wunused-value
           Warn whenever a statement computes a result that is explicitly not
           used.

           To suppress this warning cast the expression to void.

       -Wunused
           All all the above -Wunused options combined.

           In order to get a warning about an unused function parameter, you
           must either specify -W -Wunused or separately specify
           -Wunused-parameter.

       -Wuninitialized
           Warn if an automatic variable is used without first being initial-
           ized or if a variable may be clobbered by a "setjmp" call.

           These warnings are possible only in optimizing compilation, because
           they require data flow information that is computed only when opti-
           mizing.  If you don't specify -O, you simply won't get these warn-
           ings.

           These warnings occur only for variables that are candidates for
           register allocation.  Therefore, they do not occur for a variable
           that is declared "volatile", or whose address is taken, or whose
           size is other than 1, 2, 4 or 8 bytes.  Also, they do not occur for
           structures, unions or arrays, even when they are in registers.

           Note that there may be no warning about a variable that is used
           only to compute a value that itself is never used, because such
           computations may be deleted by data flow analysis before the warn-
           ings are printed.

           These warnings are made optional because GCC is not smart enough to
           see all the reasons why the code might be correct despite appearing
           to have an error.  Here is one example of how this can happen:

                   {
                     int x;
                     switch (y)
                       {
                       case 1: x = 1;
                         break;
                       case 2: x = 4;
                         break;
                       case 3: x = 5;

                     if (change_y) save_y = y, y = new_y;
                     ...
                     if (change_y) y = save_y;
                   }

           This has no bug because "save_y" is used only if it is set.

           This option also warns when a non-volatile automatic variable might
           be changed by a call to "longjmp".  These warnings as well are
           possible only in optimizing compilation.

           The compiler sees only the calls to "setjmp".  It cannot know where
           "longjmp" will be called; in fact, a signal handler could call it
           at any point in the code.  As a result, you may get a warning even
           when there is in fact no problem because "longjmp" cannot in fact
           be called at the place which would cause a problem.

           Some spurious warnings can be avoided if you declare all the func-
           tions you use that never return as "noreturn".

       -Wreorder (C++ only)
           Warn when the order of member initializers given in the code does
           not match the order in which they must be executed.  For instance:

       -Wunknown-pragmas
           Warn when a #pragma directive is encountered which is not under-
           stood by GCC.  If this command line option is used, warnings will
           even be issued for unknown pragmas in system header files.  This is
           not the case if the warnings were only enabled by the -Wall command
           line option.

       -Wall
           All of the above -W options combined.  This enables all the warn-
           ings about constructions that some users consider questionable, and
           that are easy to avoid (or modify to prevent the warning), even in
           conjunction with macros.

       -Wdiv-by-zero
           Warn about compile-time integer division by zero.  This is default.
           To inhibit the warning messages, use -Wno-div-by-zero.  Floating
           point division by zero is not warned about, as it can be a legiti-
           mate way of obtaining infinities and NaNs.

       -Wmultichar
           Warn if a multicharacter constant ('FOOF') is used.  This is
           default.  To inhibit the warning messages, use -Wno-multichar.
           Usually they indicate a typo in the user's code, as they have
           implementation-defined values, and should not be used in portable
           code.

       -Wsystem-headers
           Print warning messages for constructs found in system header files.
           Warnings from system headers are normally suppressed, on the
           assumption that they usually do not indicate real problems and
           would only make the compiler output harder to read.  Using this
           command line option tells GCC to emit warnings from system headers
           as if they occurred in user code.  However, note that using -Wall

       -W  Print extra warning messages for these events:

              A function can return either with or without a value.  (Falling
               off the end of the function body is considered returning with-
               out a value.)  For example, this function would evoke such a
               warning:

                       foo (a)
                       {
                         if (a > 0)
                           return a;
                       }

              An expression-statement or the left-hand side of a comma
               expression contains no side effects.  To suppress the warning,
               cast the unused expression to void.  For example, an expression
               such as x[i,j] will cause a warning, but x[(void)i,j] will not.

              An unsigned value is compared against zero with < or <=.

              A comparison like x<=y<=z appears; this is equivalent to (x<=y
               ? 1 : 0) <= z, which is a different interpretation from that of
               ordinary mathematical notation.

              Storage-class specifiers like "static" are not the first things
               in a declaration.  According to the C Standard, this usage is
               obsolescent.

              The return type of a function has a type qualifier such as
               "const".  Such a type qualifier has no effect, since the value
               returned by a function is not an lvalue.  (But don't warn about
               the GNU extension of "volatile void" return types.  That exten-
               sion will be warned about if -pedantic is specified.)

              If -Wall or -Wunused is also specified, warn about unused argu-
               ments.

              A comparison between signed and unsigned values could produce
               an incorrect result when the signed value is converted to
               unsigned.  (But don't warn if -Wno-sign-compare is also speci-
               fied.)

              An aggregate has a partly bracketed initializer.  For example,
               the following code would evoke such a warning, because braces
               are missing around the initializer for "x.h":

                       struct s { int f, g; };
                       struct t { struct s h; int i; };
                       struct t x = { 1, 2, 3 };

              An aggregate has an initializer which does not initialize all
               members.  For example, the following code would cause such a
               warning, because "x.h" would be implicitly initialized to zero:

                       struct s { int f, g, h; };
                       struct s x = { 3, 4 };

           output, but that's a different problem).  In particular, instead of
           testing for equality, you would check to see whether the two values
           have ranges that overlap; and this is done with the relational
           operators, so equality comparisons are probably mistaken.

       -Wtraditional (C only)
           Warn about certain constructs that behave differently in tradi-
           tional and ISO C.  Also warn about ISO C constructs that have no
           traditional C equivalent, and/or problematic constructs which
           should be avoided.

              Macro parameters that appear within string literals in the
               macro body.  In traditional C macro replacement takes place
               within string literals, but does not in ISO C.

              In traditional C, some preprocessor directives did not exist.
               Traditional preprocessors would only consider a line to be a
               directive if the # appeared in column 1 on the line.  Therefore
               -Wtraditional warns about directives that traditional C under-
               stands but would ignore because the # does not appear as the
               first character on the line.  It also suggests you hide
               directives like #pragma not understood by traditional C by
               indenting them.  Some traditional implementations would not
               recognize #elif, so it suggests avoiding it altogether.

              A function-like macro that appears without arguments.

              The unary plus operator.

              The U integer constant suffix, or the F or L floating point
               constant suffixes.  (Traditional C does support the L suffix on
               integer constants.)  Note, these suffixes appear in macros
               defined in the system headers of most modern systems, e.g. the
               _MIN/_MAX macros in "<limits.h>".  Use of these macros in user
               code might normally lead to spurious warnings, however gcc's
               integrated preprocessor has enough context to avoid warning in
               these cases.

              A function declared external in one block and then used after
               the end of the block.

              A "switch" statement has an operand of type "long".

              A non-"static" function declaration follows a "static" one.
               This construct is not accepted by some traditional C compilers.

              The ISO type of an integer constant has a different width or
               signedness from its traditional type.  This warning is only
               issued if the base of the constant is ten.  I.e. hexadecimal or
               octal values, which typically represent bit patterns, are not
               warned about.

              Usage of ISO string concatenation is detected.

              Initialization of automatic aggregates.

              Identifier conflicts with labels.  Traditional C lacks a sepa-
               and vice versa.  The absence of these prototypes when compiling
               with traditional C would cause serious problems.  This is a
               subset of the possible conversion warnings, for the full set
               use -Wconversion.

       -Wundef
           Warn if an undefined identifier is evaluated in an #if directive.

       -Wshadow
           Warn whenever a local variable shadows another local variable,
           parameter or global variable or whenever a built-in function is
           shadowed.

       -Wlarger-than-len
           Warn whenever an object of larger than len bytes is defined.

       -Wpointer-arith
           Warn about anything that depends on the ``size of'' a function type
           or of "void".  GNU C assigns these types a size of 1, for conve-
           nience in calculations with "void *" pointers and pointers to func-
           tions.

       -Wbad-function-cast (C only)
           Warn whenever a function call is cast to a non-matching type.  For
           example, warn if "int malloc()" is cast to "anything *".

       -Wcast-qual
           Warn whenever a pointer is cast so as to remove a type qualifier
           from the target type.  For example, warn if a "const char *" is
           cast to an ordinary "char *".

       -Wcast-align
           Warn whenever a pointer is cast such that the required alignment of
           the target is increased.  For example, warn if a "char *" is cast
           to an "int *" on machines where integers can only be accessed at
           two- or four-byte boundaries.

       -Wwrite-strings
           When compiling C, give string constants the type "const
           char[length]" so that copying the address of one into a non-"const"
           "char *" pointer will get a warning; when compiling C++, warn about
           the deprecated conversion from string constants to "char *".  These
           warnings will help you find at compile time code that can try to
           write into a string constant, but only if you have been very care-
           ful about using "const" in declarations and prototypes.  Otherwise,
           it will just be a nuisance; this is why we did not make -Wall
           request these warnings.

       -Wconversion
           Warn if a prototype causes a type conversion that is different from
           what would happen to the same argument in the absence of a proto-
           type.  This includes conversions of fixed point to floating and
           vice versa, and conversions changing the width or signedness of a
           fixed point argument except when the same as the default promotion.

           Also, warn if a negative integer constant expression is implicitly
           converted to an unsigned type.  For example, warn about the assign-

       -Waggregate-return
           Warn if any functions that return structures or unions are defined
           or called.  (In languages where you can return an array, this also
           elicits a warning.)

       -Wstrict-prototypes (C only)
           Warn if a function is declared or defined without specifying the
           argument types.  (An old-style function definition is permitted
           without a warning if preceded by a declaration which specifies the
           argument types.)

       -Wmissing-prototypes (C only)
           Warn if a global function is defined without a previous prototype
           declaration.  This warning is issued even if the definition itself
           provides a prototype.  The aim is to detect global functions that
           fail to be declared in header files.

       -Wmissing-declarations
           Warn if a global function is defined without a previous declara-
           tion.  Do so even if the definition itself provides a prototype.
           Use this option to detect global functions that are not declared in
           header files.

       -Wmissing-noreturn
           Warn about functions which might be candidates for attribute "nore-
           turn".  Note these are only possible candidates, not absolute ones.
           Care should be taken to manually verify functions actually do not
           ever return before adding the "noreturn" attribute, otherwise sub-
           tle code generation bugs could be introduced.  You will not get a
           warning for "main" in hosted C environments.

       -Wmissing-format-attribute
           If -Wformat is enabled, also warn about functions which might be
           candidates for "format" attributes.  Note these are only possible
           candidates, not absolute ones.  GCC will guess that "format"
           attributes might be appropriate for any function that calls a func-
           tion like "vprintf" or "vscanf", but this might not always be the
           case, and some functions for which "format" attributes are appro-
           priate may not be detected.  This option has no effect unless
           -Wformat is enabled (possibly by -Wall).

       -Wno-deprecated-declarations
           Do not warn about uses of functions, variables, and types marked as
           deprecated by using the "deprecated" attribute.  (@pxref{Function
           Attributes}, @pxref{Variable Attributes}, @pxref{Type Attributes}.)

       -Wpacked
           Warn if a structure is given the packed attribute, but the packed
           attribute has no effect on the layout or size of the structure.
           Such structures may be mis-aligned for little benefit.  For
           instance, in this code, the variable "f.x" in "struct bar" will be
           misaligned even though "struct bar" does not itself have the packed
           attribute:

                   struct foo {
                     int x;
                     char a, b, c, d;

           when this happens it is possible to rearrange the fields of the
           structure to reduce the padding and so make the structure smaller.

       -Wredundant-decls
           Warn if anything is declared more than once in the same scope, even
           in cases where multiple declaration is valid and changes nothing.

       -Wnested-externs (C only)
           Warn if an "extern" declaration is encountered within a function.

       -Wunreachable-code
           Warn if the compiler detects that code will never be executed.

           This option is intended to warn when the compiler detects that at
           least a whole line of source code will never be executed, because
           some condition is never satisfied or because it is after a proce-
           dure that never returns.

           It is possible for this option to produce a warning even though
           there are circumstances under which part of the affected line can
           be executed, so care should be taken when removing apparently-
           unreachable code.

           For instance, when a function is inlined, a warning may mean that
           the line is unreachable in only one inlined copy of the function.

           This option is not made part of -Wall because in a debugging ver-
           sion of a program there is often substantial code which checks cor-
           rect functioning of the program and is, hopefully, unreachable
           because the program does work.  Another common use of unreachable
           code is to provide behavior which is selectable at compile-time.

       -Winline
           Warn if a function can not be inlined and it was declared as
           inline.

       -Wlong-long
           Warn if long long type is used.  This is default.  To inhibit the
           warning messages, use -Wno-long-long.  Flags -Wlong-long and
           -Wno-long-long are taken into account only when -pedantic flag is
           used.

       -Wdisabled-optimization
           Warn if a requested optimization pass is disabled.  This warning
           does not generally indicate that there is anything wrong with your
           code; it merely indicates that GCC's optimizers were unable to han-
           dle the code effectively.  Often, the problem is that your code is
           too big or too complex; GCC will refuse to optimize programs when
           the optimization itself is likely to take inordinate amounts of
           time.

       -Werror
           Make all warnings into errors.

       Options for Debugging Your Program or GCC

       GCC has various special options that are used for debugging either your
           debuggers crash or refuse to read the program.  If you want to con-
           trol for certain whether to generate the extra information, use
           -gstabs+, -gstabs, -gxcoff+, -gxcoff, -gdwarf-1+, -gdwarf-1, or
           -gvms (see below).

           Unlike most other C compilers, GCC allows you to use -g with -O.
           The shortcuts taken by optimized code may occasionally produce sur-
           prising results: some variables you declared may not exist at all;
           flow of control may briefly move where you did not expect it; some
           statements may not be executed because they compute constant
           results or their values were already at hand; some statements may
           execute in different places because they were moved out of loops.

           Nevertheless it proves possible to debug optimized output.  This
           makes it reasonable to use the optimizer for programs that might
           have bugs.

           The following options are useful when GCC is generated with the
           capability for more than one debugging format.

       -ggdb
           Produce debugging information for use by GDB.  This means to use
           the most expressive format available (DWARF 2, stabs, or the native
           format if neither of those are supported), including GDB extensions
           if at all possible.

       -gstabs
           Produce debugging information in stabs format (if that is sup-
           ported), without GDB extensions.  This is the format used by DBX on
           most BSD systems.  On MIPS, Alpha and System V Release 4 systems
           this option produces stabs debugging output which is not understood
           by DBX or SDB.  On System V Release 4 systems this option requires
           the GNU assembler.

       -gstabs+
           Produce debugging information in stabs format (if that is sup-
           ported), using GNU extensions understood only by the GNU debugger
           (GDB).  The use of these extensions is likely to make other debug-
           gers crash or refuse to read the program.

       -gcoff
           Produce debugging information in COFF format (if that is sup-
           ported).  This is the format used by SDB on most System V systems
           prior to System V Release 4.

       -gxcoff
           Produce debugging information in XCOFF format (if that is sup-
           ported).  This is the format used by the DBX debugger on IBM
           RS/6000 systems.

       -gxcoff+
           Produce debugging information in XCOFF format (if that is sup-
           ported), using GNU extensions understood only by the GNU debugger
           (GDB).  The use of these extensions is likely to make other debug-
           gers crash or refuse to read the program, and may cause assemblers
           other than the GNU assembler (GAS) to fail with an error.

           debuggers crash or refuse to read the program.

       -gdwarf-2
           Produce debugging information in DWARF version 2 format (if that is
           supported).  This is the format used by DBX on IRIX 6.

       -gvms
           Produce debugging information in VMS debug format (if that is sup-
           ported).  This is the format used by DEBUG on VMS systems.

       -glevel
       -ggdblevel
       -gstabslevel
       -gcofflevel
       -gxcofflevel
       -gvmslevel
           Request debugging information and also use level to specify how
           much information.  The default level is 2.

           Level 1 produces minimal information, enough for making backtraces
           in parts of the program that you don't plan to debug.  This
           includes descriptions of functions and external variables, but no
           information about local variables and no line numbers.

           Level 3 includes extra information, such as all the macro defini-
           tions present in the program.  Some debuggers support macro expan-
           sion when you use -g3.

           Note that in order to avoid confusion between DWARF1 debug level 2,
           and DWARF2, neither -gdwarf nor -gdwarf-2 accept a concatenated
           debug level.  Instead use an additional -glevel option to change
           the debug level for DWARF1 or DWARF2.

       -p  Generate extra code to write profile information suitable for the
           analysis program "prof".  You must use this option when compiling
           the source files you want data about, and you must also use it when
           linking.

       -pg Generate extra code to write profile information suitable for the
           analysis program "gprof".  You must use this option when compiling
           the source files you want data about, and you must also use it when
           linking.

       -Q  Makes the compiler print out each function name as it is compiled,
           and print some statistics about each pass when it finishes.

       -ftime-report
           Makes the compiler print some statistics about the time consumed by
           each pass when it finishes.

       -fmem-report
           Makes the compiler print some statistics about permanent memory
           allocation when it finishes.

       -fprofile-arcs
           Instrument arcs during compilation to generate coverage data or for
           profile-directed block ordering.  During execution the program
           ties.

           The other use of -fprofile-arcs is for use with "gcov", when it is
           used with the -ftest-coverage option.

           With -fprofile-arcs, for each function of your program GCC creates
           a program flow graph, then finds a spanning tree for the graph.
           Only arcs that are not on the spanning tree have to be instru-
           mented: the compiler adds code to count the number of times that
           these arcs are executed.  When an arc is the only exit or only
           entrance to a block, the instrumentation code can be added to the
           block; otherwise, a new basic block must be created to hold the
           instrumentation code.

       -ftest-coverage
           Create data files for the gcov code-coverage utility.  The data
           file names begin with the name of your source file:

           sourcename.bb
               A mapping from basic blocks to line numbers, which "gcov" uses
               to associate basic block execution counts with line numbers.

           sourcename.bbg
               A list of all arcs in the program flow graph.  This allows
               "gcov" to reconstruct the program flow graph, so that it can
               compute all basic block and arc execution counts from the
               information in the "sourcename.da" file.

           Use -ftest-coverage with -fprofile-arcs; the latter option adds
           instrumentation to the program, which then writes execution counts
           to another data file:

           sourcename.da
               Runtime arc execution counts, used in conjunction with the arc
               information in the file "sourcename.bbg".

           Coverage data will map better to the source files if -ftest-cover-
           age is used without optimization.

       -dletters
           Says to make debugging dumps during compilation at times specified
           by letters.  This is used for debugging the compiler.  The file
           names for most of the dumps are made by appending a pass number and
           a word to the source file name (e.g.  foo.c.00.rtl or foo.c.01.sib-
           ling).  Here are the possible letters for use in letters, and their
           meanings:

           A   Annotate the assembler output with miscellaneous debugging
               information.

           b   Dump after computing branch probabilities, to file.14.bp.

           B   Dump after block reordering, to file.29.bbro.

           c   Dump after instruction combination, to the file file.16.com-
               bine.

           E   Dump after the second if conversion, to file.26.ce2.

           f   Dump after life analysis, to file.15.life.

           F   Dump after purging "ADDRESSOF" codes, to file.09.addressof.

           g   Dump after global register allocation, to file.21.greg.

           h   Dump after finalization of EH handling code, to file.02.eh.

           k   Dump after reg-to-stack conversion, to file.28.stack.

           o   Dump after post-reload optimizations, to file.22.postreload.

           G   Dump after GCSE, to file.10.gcse.

           i   Dump after sibling call optimizations, to file.01.sibling.

           j   Dump after the first jump optimization, to file.03.jump.

           k   Dump after conversion from registers to stack, to
               file.32.stack.

           l   Dump after local register allocation, to file.20.lreg.

           L   Dump after loop optimization, to file.11.loop.

           M   Dump after performing the machine dependent reorganisation
               pass, to file.30.mach.

           n   Dump after register renumbering, to file.25.rnreg.

           N   Dump after the register move pass, to file.18.regmove.

           r   Dump after RTL generation, to file.00.rtl.

           R   Dump after the second scheduling pass, to file.27.sched2.

           s   Dump after CSE (including the jump optimization that sometimes
               follows CSE), to file.08.cse.

           S   Dump after the first scheduling pass, to file.19.sched.

           t   Dump after the second CSE pass (including the jump optimization
               that sometimes follows CSE), to file.12.cse2.

           w   Dump after the second flow pass, to file.23.flow2.

           X   Dump after SSA dead code elimination, to file.06.ssadce.

           z   Dump after the peephole pass, to file.24.peephole2.

           a   Produce all the dumps listed above.

           m   Print statistics on memory usage, at the end of the run, to
               standard error.

               suitable for viewing with VCG to file.pass.vcg.

           x   Just generate RTL for a function instead of compiling it.  Usu-
               ally used with r.

           y   Dump debugging information during parsing, to standard error.

       -fdump-unnumbered
           When doing debugging dumps (see -d option above), suppress instruc-
           tion numbers and line number note output.  This makes it more fea-
           sible to use diff on debugging dumps for compiler invocations with
           different options, in particular with and without -g.

       -fdump-translation-unit (C and C++ only)
       -fdump-translation-unit-options (C and C++ only)
           Dump a representation of the tree structure for the entire transla-
           tion unit to a file.  The file name is made by appending .tu to the
           source file name.  If the -options form is used, options controls
           the details of the dump as described for the -fdump-tree options.

       -fdump-class-hierarchy (C++ only)
       -fdump-class-hierarchy-options (C++ only)
           Dump a representation of each class's hierarchy and virtual func-
           tion table layout to a file.  The file name is made by appending
           .class to the source file name.  If the -options form is used,
           options controls the details of the dump as described for the
           -fdump-tree options.

       -fdump-tree-switch (C++ only)
       -fdump-tree-switch-options (C++ only)
           Control the dumping at various stages of processing the intermedi-
           ate language tree to a file.  The file name is generated by append-
           ing a switch specific suffix to the source file name.  If the
           -options form is used, options is a list of - separated options
           that control the details of the dump. Not all options are applica-
           ble to all dumps, those which are not meaningful will be ignored.
           The following options are available

           address
               Print the address of each node.  Usually this is not meaningful
               as it changes according to the environment and source file. Its
               primary use is for tying up a dump file with a debug environ-
               ment.

           slim
               Inhibit dumping of members of a scope or body of a function
               merely because that scope has been reached. Only dump such
               items when they are directly reachable by some other path.

           all Turn on all options.

           The following tree dumps are possible:

           original
               Dump before any tree based optimization, to file.original.

           optimized
           in which case it is output to the usual dump listing file, .sched
           or .sched2 respectively.  However for n greater than nine, the out-
           put is always printed to standard error.

           For n greater than zero, -fsched-verbose outputs the same informa-
           tion as -dRS.  For n greater than one, it also output basic block
           probabilities, detailed ready list information and unit/insn info.
           For n greater than two, it includes RTL at abort point, control-
           flow and regions info.  And for n over four, -fsched-verbose also
           includes dependence info.

       -fpretend-float
           When running a cross-compiler, pretend that the target machine uses
           the same floating point format as the host machine.  This causes
           incorrect output of the actual floating constants, but the actual
           instruction sequence will probably be the same as GCC would make
           when running on the target machine.

       -save-temps
           Store the usual ``temporary'' intermediate files permanently; place
           them in the current directory and name them based on the source
           file.  Thus, compiling foo.c with -c -save-temps would produce
           files foo.i and foo.s, as well as foo.o.  This creates a prepro-
           cessed foo.i output file even though the compiler now normally uses
           an integrated preprocessor.

       -time
           Report the CPU time taken by each subprocess in the compilation
           sequence.  For C source files, this is the compiler proper and
           assembler (plus the linker if linking is done).  The output looks
           like this:

                   # cc1 0.12 0.01
                   # as 0.00 0.01

           The first number on each line is the ``user time,'' that is time
           spent executing the program itself.  The second number is ``system
           time,'' time spent executing operating system routines on behalf of
           the program.  Both numbers are in seconds.

       -print-file-name=library
           Print the full absolute name of the library file library that would
           be used when linking---and don't do anything else.  With this
           option, GCC does not compile or link anything; it just prints the
           file name.

       -print-multi-directory
           Print the directory name corresponding to the multilib selected by
           any other switches present in the command line.  This directory is
           supposed to exist in GCC_EXEC_PREFIX.

       -print-multi-lib
           Print the mapping from multilib directory names to compiler
           switches that enable them.  The directory name is separated from
           the switches by ;, and each switch starts with an @} instead of the
           @samp{-, without spaces between multiple switches.  This is sup-
           posed to ease shell-processing.

                   gcc -nostdlib <files>... `gcc -print-libgcc-file-name`

       -print-search-dirs
           Print the name of the configured installation directory and a list
           of program and library directories gcc will search---and don't do
           anything else.

           This is useful when gcc prints the error message installation prob-
           lem, cannot exec cpp0: No such file or directory.  To resolve this
           you either need to put cpp0 and the other compiler components where
           gcc expects to find them, or you can set the environment variable
           GCC_EXEC_PREFIX to the directory where you installed them.  Don't
           forget the trailing '/'.

       -dumpmachine
           Print the compiler's target machine (for example,
           i686-pc-linux-gnu)---and don't do anything else.

       -dumpversion
           Print the compiler version (for example, 3.0)---and don't do any-
           thing else.

       -dumpspecs
           Print the compiler's built-in specs---and don't do anything else.
           (This is used when GCC itself is being built.)

       Options That Control Optimization

       These options control various sorts of optimizations:

       -O
       -O1 Optimize.  Optimizing compilation takes somewhat more time, and a
           lot more memory for a large function.

           Without -O, the compiler's goal is to reduce the cost of compila-
           tion and to make debugging produce the expected results.  State-
           ments are independent: if you stop the program with a breakpoint
           between statements, you can then assign a new value to any variable
           or change the program counter to any other statement in the func-
           tion and get exactly the results you would expect from the source
           code.

           With -O, the compiler tries to reduce code size and execution time,
           without performing any optimizations that take a great deal of com-
           pilation time.

       -O2 Optimize even more.  GCC performs nearly all supported optimiza-
           tions that do not involve a space-speed tradeoff.  The compiler
           does not perform loop unrolling or function inlining when you spec-
           ify -O2.  As compared to -O, this option increases both compilation
           time and the performance of the generated code.

           -O2 turns on all optional optimizations except for loop unrolling,
           function inlining, and register renaming.  It also turns on the
           -fforce-mem option on all machines and frame pointer elimination on
           machines where doing so does not interfere with debugging.

       -Os Optimize for size.  -Os enables all -O2 optimizations that do not
           typically increase code size.  It also performs further optimiza-
           tions designed to reduce code size.

           If you use multiple -O options, with or without level numbers, the
           last such option is the one that is effective.

       Options of the form -fflag specify machine-independent flags.  Most
       flags have both positive and negative forms; the negative form of -ffoo
       would be -fno-foo.  In the table below, only one of the forms is
       listed---the one which is not the default.  You can figure out the
       other form by either removing no- or adding it.

       -ffloat-store
           Do not store floating point variables in registers, and inhibit
           other options that might change whether a floating point value is
           taken from a register or memory.

           This option prevents undesirable excess precision on machines such
           as the 68000 where the floating registers (of the 68881) keep more
           precision than a "double" is supposed to have.  Similarly for the
           x86 architecture.  For most programs, the excess precision does
           only good, but a few programs rely on the precise definition of
           IEEE floating point.  Use -ffloat-store for such programs, after
           modifying them to store all pertinent intermediate computations
           into variables.

       -fno-default-inline
           Do not make member functions inline by default merely because they
           are defined inside the class scope (C++ only).  Otherwise, when you
           specify -O, member functions defined inside class scope are com-
           piled inline by default; i.e., you don't need to add inline in
           front of the member function name.

       -fno-defer-pop
           Always pop the arguments to each function call as soon as that
           function returns.  For machines which must pop arguments after a
           function call, the compiler normally lets arguments accumulate on
           the stack for several function calls and pops them all at once.

       -fforce-mem
           Force memory operands to be copied into registers before doing
           arithmetic on them.  This produces better code by making all memory
           references potential common subexpressions.  When they are not com-
           mon subexpressions, instruction combination should eliminate the
           separate register-load.  The -O2 option turns on this option.

       -fforce-addr
           Force memory address constants to be copied into registers before
           doing arithmetic on them.  This may produce better code just as
           -fforce-mem may.

       -fomit-frame-pointer
           Don't keep the frame pointer in a register for functions that don't
           need one.  This avoids the instructions to save, set up and restore
           frame pointers; it also makes an extra register available in many
           Optimize sibling and tail recursive calls.

       -ftrapv
           This option generates traps for signed overflow on addition, sub-
           traction, multiplication operations.

       -fno-inline
           Don't pay attention to the "inline" keyword.  Normally this option
           is used to keep the compiler from expanding any functions inline.
           Note that if you are not optimizing, no functions can be expanded
           inline.

       -finline-functions
           Integrate all simple functions into their callers.  The compiler
           heuristically decides which functions are simple enough to be worth
           integrating in this way.

           If all calls to a given function are integrated, and the function
           is declared "static", then the function is normally not output as
           assembler code in its own right.

       -finline-limit=n
           By default, gcc limits the size of functions that can be inlined.
           This flag allows the control of this limit for functions that are
           explicitly marked as inline (ie marked with the inline keyword or
           defined within the class definition in c++).  n is the size of
           functions that can be inlined in number of pseudo instructions (not
           counting parameter handling).  The default value of n is 600.
           Increasing this value can result in more inlined code at the cost
           of compilation time and memory consumption.  Decreasing usually
           makes the compilation faster and less code will be inlined (which
           presumably means slower programs).  This option is particularly
           useful for programs that use inlining heavily such as those based
           on recursive templates with C++.

           Note: pseudo instruction represents, in this particular context, an
           abstract measurement of function's size.  In no way, it represents
           a count of assembly instructions and as such its exact meaning
           might change from one release to an another.

       -fkeep-inline-functions
           Even if all calls to a given function are integrated, and the func-
           tion is declared "static", nevertheless output a separate run-time
           callable version of the function.  This switch does not affect
           "extern inline" functions.

       -fkeep-static-consts
           Emit variables declared "static const" when optimization isn't
           turned on, even if the variables aren't referenced.

           GCC enables this option by default.  If you want to force the com-
           piler to check if the variable was referenced, regardless of
           whether or not optimization is turned on, use the
           -fno-keep-static-consts option.

       -fmerge-constants
           Attempt to merge identical constants (string constants and floating
           This option implies -fmerge-constants.  In addition to -fmerge-con-
           stants this considers e.g. even constant initialized arrays or ini-
           tialized constant variables with integral or floating point types.
           Languages like C or C++ require each non-automatic variable to have
           distinct location, so using this option will result in non-conform-
           ing behavior.

       -fno-branch-count-reg
           Do not use ``decrement and branch'' instructions on a count regis-
           ter, but instead generate a sequence of instructions that decrement
           a register, compare it against zero, then branch based upon the
           result.  This option is only meaningful on architectures that sup-
           port such instructions, which include x86, PowerPC, IA-64 and
           S/390.

       -fno-function-cse
           Do not put function addresses in registers; make each instruction
           that calls a constant function contain the function's address
           explicitly.

           This option results in less efficient code, but some strange hacks
           that alter the assembler output may be confused by the optimiza-
           tions performed when this option is not used.

       -ffast-math
           Sets -fno-math-errno, -funsafe-math-optimizations, and -fno-trap-
           ping-math.

           This option causes the preprocessor macro "__FAST_MATH__" to be
           defined.

           This option should never be turned on by any -O option since it can
           result in incorrect output for programs which depend on an exact
           implementation of IEEE or ISO rules/specifications for math func-
           tions.

       -fno-math-errno
           Do not set ERRNO after calling math functions that are executed
           with a single instruction, e.g., sqrt.  A program that relies on
           IEEE exceptions for math error handling may want to use this flag
           for speed while maintaining IEEE arithmetic compatibility.

           This option should never be turned on by any -O option since it can
           result in incorrect output for programs which depend on an exact
           implementation of IEEE or ISO rules/specifications for math func-
           tions.

           The default is -fmath-errno.

       -funsafe-math-optimizations
           Allow optimizations for floating-point arithmetic that (a) assume
           that arguments and results are valid and (b) may violate IEEE or
           ANSI standards.  When used at link-time, it may include libraries
           or startup files that change the default FPU control word or other
           similar optimizations.

           This option should never be turned on by any -O option since it can
           if one relies on ``non-stop'' IEEE arithmetic, for example.

           This option should never be turned on by any -O option since it can
           result in incorrect output for programs which depend on an exact
           implementation of IEEE or ISO rules/specifications for math func-
           tions.

           The default is -ftrapping-math.

       -fbounds-check
           For front-ends that support it, generate additional code to check
           that indices used to access arrays are within the declared range.
           This is currenly only supported by the Java and Fortran 77
           front-ends, where this option defaults to true and false respec-
           tively.

       The following options control specific optimizations.  The -O2 option
       turns on all of these optimizations except -funroll-loops and -fun-
       roll-all-loops.  On most machines, the -O option turns on the
       -fthread-jumps and -fdelayed-branch options, but specific machines may
       handle it differently.

       You can use the following flags in the rare cases when ``fine-tuning''
       of optimizations to be performed is desired.

       Not all of the optimizations performed by GCC have -f options to con-
       trol them.

       -fstrength-reduce
           Perform the optimizations of loop strength reduction and elimina-
           tion of iteration variables.

       -fthread-jumps
           Perform optimizations where we check to see if a jump branches to a
           location where another comparison subsumed by the first is found.
           If so, the first branch is redirected to either the destination of
           the second branch or a point immediately following it, depending on
           whether the condition is known to be true or false.

       -fcse-follow-jumps
           In common subexpression elimination, scan through jump instructions
           when the target of the jump is not reached by any other path.  For
           example, when CSE encounters an "if" statement with an "else"
           clause, CSE will follow the jump when the condition tested is
           false.

       -fcse-skip-blocks
           This is similar to -fcse-follow-jumps, but causes CSE to follow
           jumps which conditionally skip over blocks.  When CSE encounters a
           simple "if" statement with no else clause, -fcse-skip-blocks causes
           CSE to follow the jump around the body of the "if".

       -frerun-cse-after-loop
           Re-run common subexpression elimination after loop optimizations
           has been performed.

       -frerun-loop-opt
           the command line.

       -fgcse-lm
           When -fgcse-lm is enabled, global common subexpression elimination
           will attempt to move loads which are only killed by stores into
           themselves.  This allows a loop containing a load/store sequence to
           be changed to a load outside the loop, and a copy/store within the
           loop.

       -fgcse-sm
           When -fgcse-sm is enabled, A store motion pass is run after global
           common subexpression elimination.  This pass will attempt to move
           stores out of loops.  When used in conjunction with -fgcse-lm,
           loops containing a load/store sequence can be changed to a load
           before the loop and a store after the loop.

       -fdelete-null-pointer-checks
           Use global dataflow analysis to identify and eliminate useless
           checks for null pointers.  The compiler assumes that dereferencing
           a null pointer would have halted the program.  If a pointer is
           checked after it has already been dereferenced, it cannot be null.

           In some environments, this assumption is not true, and programs can
           safely dereference null pointers.  Use
           -fno-delete-null-pointer-checks to disable this optimization for
           programs which depend on that behavior.

       -fexpensive-optimizations
           Perform a number of minor optimizations that are relatively expen-
           sive.

       -foptimize-register-move
       -fregmove
           Attempt to reassign register numbers in move instructions and as
           operands of other simple instructions in order to maximize the
           amount of register tying.  This is especially helpful on machines
           with two-operand instructions.  GCC enables this optimization by
           default with -O2 or higher.

           Note -fregmove and -foptimize-register-move are the same optimiza-
           tion.

       -fdelayed-branch
           If supported for the target machine, attempt to reorder instruc-
           tions to exploit instruction slots available after delayed branch
           instructions.

       -fschedule-insns
           If supported for the target machine, attempt to reorder instruc-
           tions to eliminate execution stalls due to required data being
           unavailable.  This helps machines that have slow floating point or
           memory load instructions by allowing other instructions to be
           issued until the result of the load or floating point instruction
           is required.

       -fschedule-insns2
           Similar to -fschedule-insns, but requests an additional pass of

       -fno-sched-spec
           Don't allow speculative motion of non-load instructions.  This is
           normally enabled by default when scheduling before register alloca-
           tion, i.e.  with -fschedule-insns or at -O2 or higher.

       -fsched-spec-load
           Allow speculative motion of some load instructions.  This only
           makes sense when scheduling before register allocation, i.e. with
           -fschedule-insns or at -O2 or higher.

       -fsched-spec-load-dangerous
           Allow speculative motion of more load instructions.  This only
           makes sense when scheduling before register allocation, i.e. with
           -fschedule-insns or at -O2 or higher.

       -ffunction-sections
       -fdata-sections
           Place each function or data item into its own section in the output
           file if the target supports arbitrary sections.  The name of the
           function or the name of the data item determines the section's name
           in the output file.

           Use these options on systems where the linker can perform optimiza-
           tions to improve locality of reference in the instruction space.
           HPPA processors running HP-UX and Sparc processors running Solaris
           2 have linkers with such optimizations.  Other systems using the
           ELF object format as well as AIX may have these optimizations in
           the future.

           Only use these options when there are significant benefits from
           doing so.  When you specify these options, the assembler and linker
           will create larger object and executable files and will also be
           slower.  You will not be able to use "gprof" on all systems if you
           specify this option and you may have problems with debugging if you
           specify both this option and -g.

       -fcaller-saves
           Enable values to be allocated in registers that will be clobbered
           by function calls, by emitting extra instructions to save and
           restore the registers around such calls.  Such allocation is done
           only when it seems to result in better code than would otherwise be
           produced.

           This option is always enabled by default on certain machines, usu-
           ally those which have no call-preserved registers to use instead.

           For all machines, optimization level 2 and higher enables this flag
           by default.

       -funroll-loops
           Unroll loops whose number of iterations can be determined at com-
           pile time or upon entry to the loop.  -funroll-loops implies both
           -fstrength-reduce and -frerun-cse-after-loop.  This option makes
           code larger, and may or may not make it run faster.

       -funroll-all-loops

       -fmove-all-movables
           Forces all invariant computations in loops to be moved outside the
           loop.

       -freduce-all-givs
           Forces all general-induction variables in loops to be
           strength-reduced.

           Note: When compiling programs written in Fortran, -fmove-all-mov-
           ables and -freduce-all-givs are enabled by default when you use the
           optimizer.

           These options may generate better or worse code; results are highly
           dependent on the structure of loops within the source code.

           These two options are intended to be removed someday, once they
           have helped determine the efficacy of various approaches to improv-
           ing loop optimizations.

           Please let us (<gcc@gcc.gnu.org> and <fortran@gnu.org>) know how
           use of these options affects the performance of your production
           code.  We're very interested in code that runs slower when these
           options are enabled.

       -fno-peephole
       -fno-peephole2
           Disable any machine-specific peephole optimizations.  The differ-
           ence between -fno-peephole and -fno-peephole2 is in how they are
           implemented in the compiler; some targets use one, some use the
           other, a few use both.

       -fbranch-probabilities
           After running a program compiled with -fprofile-arcs, you can com-
           pile it a second time using -fbranch-probabilities, to improve
           optimizations based on the number of times each branch was taken.
           When the program compiled with -fprofile-arcs exits it saves arc
           execution counts to a file called sourcename.da for each source
           file  The information in this data file is very dependent on the
           structure of the generated code, so you must use the same source
           code and the same optimization options for both compilations.

           With -fbranch-probabilities, GCC puts a REG_EXEC_COUNT note on the
           first instruction of each basic block, and a REG_BR_PROB note on
           each JUMP_INSN and CALL_INSN.  These can be used to improve opti-
           mization.  Currently, they are only used in one place: in reorg.c,
           instead of guessing which path a branch is mostly to take, the
           REG_BR_PROB values are used to exactly determine which path is
           taken more often.

       -fno-guess-branch-probability
           Do not guess branch probabilities using a randomized model.

           Sometimes gcc will opt to use a randomized model to guess branch
           probabilities, when none are available from either profiling feed-
           back (-fprofile-arcs) or __builtin_expect.  This means that differ-
           ent runs of the compiler on the same program may produce different
           Allows the compiler to assume the strictest aliasing rules applica-
           ble to the language being compiled.  For C (and C++), this acti-
           vates optimizations based on the type of expressions.  In particu-
           lar, an object of one type is assumed never to reside at the same
           address as an object of a different type, unless the types are
           almost the same.  For example, an "unsigned int" can alias an
           "int", but not a "void*" or a "double".  A character type may alias
           any other type.

           Pay special attention to code like this:

                   union a_union {
                     int i;
                     double d;
                   };

                   int f() {
                     a_union t;
                     t.d = 3.0;
                     return t.i;
                   }

           The practice of reading from a different union member than the one
           most recently written to (called ``type-punning'') is common.  Even
           with -fstrict-aliasing, type-punning is allowed, provided the mem-
           ory is accessed through the union type.  So, the code above will
           work as expected.  However, this code might not:

                   int f() {
                     a_union t;
                     int* ip;
                     t.d = 3.0;
                     ip = &t.i;
                     return *ip;
                   }

           Every language that wishes to perform language-specific alias anal-
           ysis should define a function that computes, given an "tree" node,
           an alias set for the node.  Nodes in different alias sets are not
           allowed to alias.  For an example, see the C front-end function
           "c_get_alias_set".

       -falign-functions
       -falign-functions=n
           Align the start of functions to the next power-of-two greater than
           n, skipping up to n bytes.  For instance, -falign-functions=32
           aligns functions to the next 32-byte boundary, but -falign-func-
           tions=24 would align to the next 32-byte boundary only if this can
           be done by skipping 23 bytes or less.

           -fno-align-functions and -falign-functions=1 are equivalent and
           mean that functions will not be aligned.

           Some assemblers only support this flag when n is a power of two; in
           that case, it is rounded up.

           If n is not specified, use a machine-dependent default.
           than this value, then their values are used instead.

           If n is not specified, use a machine-dependent default which is
           very likely to be 1, meaning no alignment.

       -falign-loops
       -falign-loops=n
           Align loops to a power-of-two boundary, skipping up to n bytes like
           -falign-functions.  The hope is that the loop will be executed many
           times, which will make up for any execution of the dummy opera-
           tions.

           If n is not specified, use a machine-dependent default.

       -falign-jumps
       -falign-jumps=n
           Align branch targets to a power-of-two boundary, for branch targets
           where the targets can only be reached by jumping, skipping up to n
           bytes like -falign-functions.  In this case, no dummy operations
           need be executed.

           If n is not specified, use a machine-dependent default.

       -fssa
           Perform optimizations in static single assignment form.  Each func-
           tion's flow graph is translated into SSA form, optimizations are
           performed, and the flow graph is translated back from SSA form.
           Users should not specify this option, since it is not yet ready for
           production use.

       -fssa-ccp
           Perform Sparse Conditional Constant Propagation in SSA form.
           Requires -fssa.  Like -fssa, this is an experimental feature.

       -fssa-dce
           Perform aggressive dead-code elimination in SSA form.  Requires
           -fssa.  Like -fssa, this is an experimental feature.

       -fsingle-precision-constant
           Treat floating point constant as single precision constant instead
           of implicitly converting it to double precision constant.

       -frename-registers
           Attempt to avoid false dependencies in scheduled code by making use
           of registers left over after register allocation.  This optimiza-
           tion will most benefit processors with lots of registers.  It can,
           however, make debugging impossible, since variables will no longer
           stay in a ``home register''.

       -fno-cprop-registers
           After register allocation and post-register allocation instruction
           splitting, we perform a copy-propagation pass to try to reduce
           scheduling dependencies and occasionally eliminate the copy.

       --param name=value
           In some places, GCC uses various constants to control the amount of
           optimization that is done.  For example, GCC will not inline func-
               an instruction to fill a delay slot.  If more than this arbi-
               trary number of instructions is searched, the time savings from
               filling the delay slot will be minimal so stop searching.
               Increasing values mean more aggressive optimization, making the
               compile time increase with probably small improvement in exe-
               cutable run time.

           max-delay-slot-live-search
               When trying to fill delay slots, the maximum number of instruc-
               tions to consider when searching for a block with valid live
               register information.  Increasing this arbitrarily chosen value
               means more aggressive optimization, increasing the compile
               time.  This parameter should be removed when the delay slot
               code is rewritten to maintain the control-flow graph.

           max-gcse-memory
               The approximate maximum amount of memory that will be allocated
               in order to perform the global common subexpression elimination
               optimization.  If more memory than specified is required, the
               optimization will not be done.

           max-gcse-passes
               The maximum number of passes of GCSE to run.

           max-pending-list-length
               The maximum number of pending dependencies scheduling will
               allow before flushing the current state and starting over.
               Large functions with few branches or calls can create exces-
               sively large lists which needlessly consume memory and
               resources.

           max-inline-insns
               If an function contains more than this many instructions, it
               will not be inlined.  This option is precisely equivalent to
               -finline-limit.

       Options Controlling the Preprocessor

       These options control the C preprocessor, which is run on each C source
       file before actual compilation.

       If you use the -E option, nothing is done except preprocessing.  Some
       of these options make sense only together with -E because they cause
       the preprocessor output to be unsuitable for actual compilation.

       You can use -Wp,option to bypass the compiler driver and pass option
       directly through to the preprocessor.  If option contains commas, it is
       split into multiple options at the commas.  However, many options are
       modified, translated or interpreted by the compiler driver before being
       passed to the preprocessor, and -Wp forcibly bypasses this phase.  The
       preprocessor's direct interface is undocumented and subject to change,
       so whenever possible you should avoid using -Wp and let the driver han-
       dle the options instead.

       -D name
           Predefine name as a macro, with definition 1.

           equals sign (if any).  Parentheses are meaningful to most shells,
           so you will need to quote the option.  With sh and csh,
           -D'name(args...)=definition' works.

           -D and -U options are processed in the order they are given on the
           command line.  All -imacros file and -include file options are pro-
           cessed after all -D and -U options.

       -U name
           Cancel any previous definition of name, either built in or provided
           with a -D option.

       -undef
           Do not predefine any system-specific macros.  The common predefined
           macros remain defined.

       -I dir
           Add the directory dir to the list of directories to be searched for
           header files.  Directories named by -I are searched before the
           standard system include directories.

           It is dangerous to specify a standard system include directory in
           an -I option.  This defeats the special treatment of system headers
           .  It can also defeat the repairs to buggy system headers which GCC
           makes when it is installed.

       -o file
           Write output to file.  This is the same as specifying file as the
           second non-option argument to cpp.  gcc has a different interpreta-
           tion of a second non-option argument, so you must use -o to specify
           the output file.

       -Wall
           Turns on all optional warnings which are desirable for normal code.
           At present this is -Wcomment and -Wtrigraphs.  Note that many of
           the preprocessor's warnings are on by default and have no options
           to control them.

       -Wcomment
       -Wcomments
           Warn whenever a comment-start sequence /* appears in a /* comment,
           or whenever a backslash-newline appears in a // comment.  (Both
           forms have the same effect.)

       -Wtrigraphs
           Warn if any trigraphs are encountered.  This option used to take
           effect only if -trigraphs was also specified, but now works inde-
           pendently.  Warnings are not given for trigraphs within comments,
           as they do not affect the meaning of the program.

       -Wtraditional
           Warn about certain constructs that behave differently in tradi-
           tional and ISO C.  Also warn about ISO C constructs that have no
           traditional C equivalent, and problematic constructs which should
           be avoided.

       -Wimport
           warnings will be rejected.

       -Wsystem-headers
           Issue warnings for code in system headers.  These are normally
           unhelpful in finding bugs in your own code, therefore suppressed.
           If you are responsible for the system library, you may want to see
           them.

       -w  Suppress all warnings, including those which GNU CPP issues by
           default.

       -pedantic
           Issue all the mandatory diagnostics listed in the C standard.  Some
           of them are left out by default, since they trigger frequently on
           harmless code.

       -pedantic-errors
           Issue all the mandatory diagnostics, and make all mandatory diag-
           nostics into errors.  This includes mandatory diagnostics that GCC
           issues without -pedantic but treats as warnings.

       -M  Instead of outputting the result of preprocessing, output a rule
           suitable for make describing the dependencies of the main source
           file.  The preprocessor outputs one make rule containing the object
           file name for that source file, a colon, and the names of all the
           included files, including those coming from -include or -imacros
           command line options.

           Unless specified explicitly (with -MT or -MQ), the object file name
           consists of the basename of the source file with any suffix
           replaced with object file suffix.  If there are many included files
           then the rule is split into several lines using \-newline.  The
           rule has no commands.

           This option does not suppress the preprocessor's debug output, such
           as -dM.  To avoid mixing such debug output with the dependency
           rules you should explicitly specify the dependency output file with
           -MF, or use an environment variable like DEPENDENCIES_OUTPUT.
           Debug output will still be sent to the regular output stream as
           normal.

           Passing -M to the driver implies -E.

       -MM Like -M but do not mention header files that are found in system
           header directories, nor header files that are included, directly or
           indirectly, from such a header.

           This implies that the choice of angle brackets or double quotes in
           an #include directive does not in itself determine whether that
           header will appear in -MM dependency output.  This is a slight
           change in semantics from GCC versions 3.0 and earlier.

       -MF file
           @anchor{-MF} When used with -M or -MM, specifies a file to write
           the dependencies to.  If no -MF switch is given the preprocessor
           sends the rules to the same place it would have sent preprocessed
           output.
           This feature is used in automatic updating of makefiles.

       -MP This option instructs CPP to add a phony target for each dependency
           other than the main file, causing each to depend on nothing.  These
           dummy rules work around errors make gives if you remove header
           files without updating the Makefile to match.

           This is typical output:

                   test.o: test.c test.h

                   test.h:

       -MT target
           Change the target of the rule emitted by dependency generation.  By
           default CPP takes the name of the main input file, including any
           path, deletes any file suffix such as .c, and appends the plat-
           form's usual object suffix.  The result is the target.

           An -MT option will set the target to be exactly the string you
           specify.  If you want multiple targets, you can specify them as a
           single argument to -MT, or use multiple -MT options.

           For example, -MT '$(objpfx)foo.o' might give

                   $(objpfx)foo.o: foo.c

       -MQ target
           Same as -MT, but it quotes any characters which are special to
           Make.  -MQ '$(objpfx)foo.o' gives

                   $$(objpfx)foo.o: foo.c

           The default target is automatically quoted, as if it were given
           with -MQ.

       -MD -MD is equivalent to -M -MF file, except that -E is not implied.
           The driver determines file based on whether an -o option is given.
           If it is, the driver uses its argument but with a suffix of .d,
           otherwise it take the basename of the input file and applies a .d
           suffix.

           If -MD is used in conjunction with -E, any -o switch is understood
           to specify the dependency output file (but @pxref{-MF}), but if
           used without -E, each -o is understood to specify a target object
           file.

           Since -E is not implied, -MD can be used to generate a dependency
           output file as a side-effect of the compilation process.

       -MMD
           Like -MD except mention only user header files, not system -header
           files.

       -x c
       -x c++
       -x objective-c

           Note: Previous versions of cpp accepted a -lang option which
           selected both the language and the standards conformance level.
           This option has been removed, because it conflicts with the -l
           option.

       -std=standard
       -ansi
           Specify the standard to which the code should conform.  Currently
           cpp only knows about the standards for C; other language standards
           will be added in the future.

           standard may be one of:

           "iso9899:1990"
           "c89"
               The ISO C standard from 1990.  c89 is the customary shorthand
               for this version of the standard.

               The -ansi option is equivalent to -std=c89.

           "iso9899:199409"
               The 1990 C standard, as amended in 1994.

           "iso9899:1999"
           "c99"
           "iso9899:199x"
           "c9x"
               The revised ISO C standard, published in December 1999.  Before
               publication, this was known as C9X.

           "gnu89"
               The 1990 C standard plus GNU extensions.  This is the default.

           "gnu99"
           "gnu9x"
               The 1999 C standard plus GNU extensions.

       -I- Split the include path.  Any directories specified with -I options
           before -I- are searched only for headers requested with
           "#include "file""; they are not searched for "#include <file>".  If
           additional directories are specified with -I options after the -I-,
           those directories are searched for all #include directives.

           In addition, -I- inhibits the use of the directory of the current
           file directory as the first search directory for "#include "file"".

       -nostdinc
           Do not search the standard system directories for header files.
           Only the directories you have specified with -I options (and the
           directory of the current file, if appropriate) are searched.

       -nostdinc++
           Do not search for header files in the C++-specific standard direc-
           tories, but do still search the other standard directories.  (This
           option is used when building the C++ library.)

           the order they appear on the command line.

       -imacros file
           Exactly like -include, except that any output produced by scanning
           file is thrown away.  Macros it defines remain defined.  This
           allows you to acquire all the macros from a header without also
           processing its declarations.

           All files specified by -imacros are processed before all files
           specified by -include.

       -idirafter dir
           Search dir for header files, but do it after all directories speci-
           fied with -I and the standard system directories have been
           exhausted.  dir is treated as a system include directory.

       -iprefix prefix
           Specify prefix as the prefix for subsequent -iwithprefix options.
           If the prefix represents a directory, you should include the final
           /.

       -iwithprefix dir
       -iwithprefixbefore dir
           Append dir to the prefix specified previously with -iprefix, and
           add the resulting directory to the include search path.
           -iwithprefixbefore puts it in the same place -I would; -iwithprefix
           puts it where -idirafter would.

           Use of these options is discouraged.

       -isystem dir
           Search dir for header files, after all directories specified by -I
           but before the standard system directories.  Mark it as a system
           directory, so that it gets the same special treatment as is applied
           to the standard system directories.

       -fpreprocessed
           Indicate to the preprocessor that the input file has already been
           preprocessed.  This suppresses things like macro expansion, tri-
           graph conversion, escaped newline splicing, and processing of most
           directives.  The preprocessor still recognizes and removes com-
           ments, so that you can pass a file preprocessed with -C to the com-
           piler without problems.  In this mode the integrated preprocessor
           is little more than a tokenizer for the front ends.

           -fpreprocessed is implicit if the input file has one of the exten-
           sions .i, .ii or .mi.  These are the extensions that GCC uses for
           preprocessed files created by -save-temps.

       -ftabstop=width
           Set the distance between tab stops.  This helps the preprocessor
           report correct column numbers in warnings or errors, even if tabs
           appear on the line.  If the value is less than 1 or greater than
           100, the option is ignored.  The default is 8.

       -fno-show-column
           Do not print column numbers in diagnostics.  This may be necessary

       -A -predicate=answer
           Cancel an assertion with the predicate predicate and answer answer.

       -A- Cancel all predefined assertions and all assertions preceding it on
           the command line.  Also, undefine all predefined macros and all
           macros preceding it on the command line.  (This is a historical
           wart and may change in the future.)

       -dCHARS
           CHARS is a sequence of one or more of the following characters, and
           must not be preceded by a space.  Other characters are interpreted
           by the compiler proper, or reserved for future versions of GCC, and
           so are silently ignored.  If you specify characters whose behavior
           conflicts, the result is undefined.

           M   Instead of the normal output, generate a list of #define direc-
               tives for all the macros defined during the execution of the
               preprocessor, including predefined macros.  This gives you a
               way of finding out what is predefined in your version of the
               preprocessor.  Assuming you have no file foo.h, the command

                       touch foo.h; cpp -dM foo.h

               will show all the predefined macros.

           D   Like M except in two respects: it does not include the prede-
               fined macros, and it outputs both the #define directives and
               the result of preprocessing.  Both kinds of output go to the
               standard output file.

           N   Like D, but emit only the macro names, not their expansions.

           I   Output #include directives in addition to the result of prepro-
               cessing.

       -P  Inhibit generation of linemarkers in the output from the preproces-
           sor.  This might be useful when running the preprocessor on some-
           thing that is not C code, and will be sent to a program which might
           be confused by the linemarkers.

       -C  Do not discard comments.  All comments are passed through to the
           output file, except for comments in processed directives, which are
           deleted along with the directive.

           You should be prepared for side effects when using -C; it causes
           the preprocessor to treat comments as tokens in their own right.
           For example, comments appearing at the start of what would be a
           directive line have the effect of turning that line into an ordi-
           nary source line, since the first token on the line is no longer a
           #.

       -gcc
           Define the macros __GNUC__, __GNUC_MINOR__ and __GNUC_PATCHLEVEL__.
           These are defined automatically when you use gcc -E; you can turn
           them off in that case with -no-gcc.

       -traditional
           -ansi options.

           The nine trigraphs and their replacements are

                   Trigraph:       ??(  ??)  ??<  ??>  ??=  ??/  ??'  ??!  ??-
                   Replacement:      [    ]    {    }    #    \    ^    |    ~

       -remap
           Enable special code to work around file systems which only permit
           very short file names, such as MS-DOS.

       -$  Forbid the use of $ in identifiers.  The C standard allows imple-
           mentations to define extra characters that can appear in identi-
           fiers.  By default GNU CPP permits $, a common extension.

       -h
       --help
       --target-help
           Print text describing all the command line options instead of pre-
           processing anything.

       -v  Verbose mode.  Print out GNU CPP's version number at the beginning
           of execution, and report the final form of the include path.

       -H  Print the name of each header file used, in addition to other nor-
           mal activities.  Each name is indented to show how deep in the
           #include stack it is.

       -version
       --version
           Print out GNU CPP's version number.  With one dash, proceed to pre-
           process as normal.  With two dashes, exit immediately.

       Passing Options to the Assembler

       You can pass options to the assembler.

       -Wa,option
           Pass option as an option to the assembler.  If option contains com-
           mas, it is split into multiple options at the commas.

       Options for Linking

       These options come into play when the compiler links object files into
       an executable output file.  They are meaningless if the compiler is not
       doing a link step.

       object-file-name
           A file name that does not end in a special recognized suffix is
           considered to name an object file or library.  (Object files are
           distinguished from libraries by the linker according to the file
           contents.)  If linking is done, these object files are used as
           input to the linker.

       -c
       -S
       -E  If any of these options is used, then the linker is not run, and
           the linker searches and processes libraries and object files in the
           order they are specified.  Thus, foo.o -lz bar.o searches library z
           after file foo.o but before bar.o.  If bar.o refers to functions in
           z, those functions may not be loaded.

           The linker searches a standard list of directories for the library,
           which is actually a file named liblibrary.a.  The linker then uses
           this file as if it had been specified precisely by name.

           The directories searched include several standard system directo-
           ries plus any that you specify with -L.

           Normally the files found this way are library files---archive files
           whose members are object files.  The linker handles an archive file
           by scanning through it for members which define symbols that have
           so far been referenced but not defined.  But if the file that is
           found is an ordinary object file, it is linked in the usual fash-
           ion.  The only difference between using an -l option and specifying
           a file name is that -l surrounds library with lib and .a and
           searches several directories.

       -lobjc
           You need this special case of the -l option in order to link an
           Objective-C program.

       -nostartfiles
           Do not use the standard system startup files when linking.  The
           standard system libraries are used normally, unless -nostdlib or
           -nodefaultlibs is used.

       -nodefaultlibs
           Do not use the standard system libraries when linking.  Only the
           libraries you specify will be passed to the linker.  The standard
           startup files are used normally, unless -nostartfiles is used.  The
           compiler may generate calls to memcmp, memset, and memcpy for Sys-
           tem V (and ISO C) environments or to bcopy and bzero for BSD envi-
           ronments.  These entries are usually resolved by entries in libc.
           These entry points should be supplied through some other mechanism
           when this option is specified.

       -nostdlib
           Do not use the standard system startup files or libraries when
           linking.  No startup files and only the libraries you specify will
           be passed to the linker.  The compiler may generate calls to mem-
           cmp, memset, and memcpy for System V (and ISO C) environments or to
           bcopy and bzero for BSD environments.  These entries are usually
           resolved by entries in libc.  These entry points should be supplied
           through some other mechanism when this option is specified.

           One of the standard libraries bypassed by -nostdlib and -nodefault-
           libs is libgcc.a, a library of internal subroutines that GCC uses
           to overcome shortcomings of particular machines, or special needs
           for some languages.

           In most cases, you need libgcc.a even when you want to avoid other
           standard libraries.  In other words, when you specify -nostdlib or
           -nodefaultlibs you should usually specify -lgcc as well.  This
           the shared libraries.  On other systems, this option has no effect.

       -shared
           Produce a shared object which can then be linked with other objects
           to form an executable.  Not all systems support this option.  For
           predictable results, you must also specify the same set of options
           that were used to generate code (-fpic, -fPIC, or model suboptions)
           when you specify this option.[1]

       -shared-libgcc
       -static-libgcc
           On systems that provide libgcc as a shared library, these options
           force the use of either the shared or static version respectively.
           If no shared version of libgcc was built when the compiler was con-
           figured, these options have no effect.

           There are several situations in which an application should use the
           shared libgcc instead of the static version.  The most common of
           these is when the application wishes to throw and catch exceptions
           across different shared libraries.  In that case, each of the
           libraries as well as the application itself should use the shared
           libgcc.

           Therefore, the G++ and GCJ drivers automatically add -shared-libgcc
           whenever you build a shared library or a main executable, because
           C++ and Java programs typically use exceptions, so this is the
           right thing to do.

           If, instead, you use the GCC driver to create shared libraries, you
           may find that they will not always be linked with the shared
           libgcc.  If GCC finds, at its configuration time, that you have a
           GNU linker that does not support option --eh-frame-hdr, it will
           link the shared version of libgcc into shared libraries by default.
           Otherwise, it will take advantage of the linker and optimize away
           the linking with the shared version of libgcc, linking with the
           static version of libgcc by default.  This allows exceptions to
           propagate through such shared libraries, without incurring reloca-
           tion costs at library load time.

           However, if a library or main executable is supposed to throw or
           catch exceptions, you must link it using the G++ or GCJ driver, as
           appropriate for the languages used in the program, or using the
           option -shared-libgcc, such that it is linked with the shared
           libgcc.

       -symbolic
           Bind references to global symbols when building a shared object.
           Warn about any unresolved references (unless overridden by the link
           editor option -Xlinker -z -Xlinker defs).  Only a few systems sup-
           port this option.

       -Xlinker option
           Pass option as an option to the linker.  You can use this to supply
           system-specific linker options which GCC does not know how to rec-
           ognize.

           If you want to pass an option that takes an argument, you must use

       -u symbol
           Pretend the symbol symbol is undefined, to force linking of library
           modules to define it.  You can use -u multiple times with different
           symbols to force loading of additional library modules.

       Options for Directory Search

       These options specify directories to search for header files, for
       libraries and for parts of the compiler:

       -Idir
           Add the directory dir to the head of the list of directories to be
           searched for header files.  This can be used to override a system
           header file, substituting your own version, since these directories
           are searched before the system header file directories.  However,
           you should not use this option to add directories that contain ven-
           dor-supplied system header files (use -isystem for that).  If you
           use more than one -I option, the directories are scanned in left-
           to-right order; the standard system directories come after.

           If a standard system include directory, or a directory specified
           with -isystem, is also specified with -I, the -I option will be
           ignored.  The directory will still be searched but as a system
           directory at its normal position in the system include chain.  This
           is to ensure that GCC's procedure to fix buggy system headers and
           the ordering for the include_next directive are not inadvertantly
           changed.  If you really need to change the search order for system
           directories, use the -nostdinc and/or -isystem options.

       -I- Any directories you specify with -I options before the -I- option
           are searched only for the case of #include "file"; they are not
           searched for #include <file>.

           If additional directories are specified with -I options after the
           -I-, these directories are searched for all #include directives.
           (Ordinarily all -I directories are used this way.)

           In addition, the -I- option inhibits the use of the current direc-
           tory (where the current input file came from) as the first search
           directory for #include "file".  There is no way to override this
           effect of -I-.  With -I. you can specify searching the directory
           which was current when the compiler was invoked.  That is not
           exactly the same as what the preprocessor does by default, but it
           is often satisfactory.

           -I- does not inhibit the use of the standard system directories for
           header files.  Thus, -I- and -nostdinc are independent.

       -Ldir
           Add directory dir to the list of directories to be searched for -l.

       -Bprefix
           This option specifies where to find the executables, libraries,
           include files, and data files of the compiler itself.

           The compiler driver program runs one or more of the subprograms
           ronment variable.

           The compiler will check to see if the path provided by the -B
           refers to a directory, and if necessary it will add a directory
           separator character at the end of the path.

           -B prefixes that effectively specify directory names also apply to
           libraries in the linker, because the compiler translates these
           options into -L options for the linker.  They also apply to
           includes files in the preprocessor, because the compiler translates
           these options into -isystem options for the preprocessor.  In this
           case, the compiler appends include to the prefix.

           The run-time support file libgcc.a can also be searched for using
           the -B prefix, if needed.  If it is not found there, the two stan-
           dard prefixes above are tried, and that is all.  The file is left
           out of the link if it is not found by those means.

           Another way to specify a prefix much like the -B prefix is to use
           the environment variable GCC_EXEC_PREFIX.

           As a special kludge, if the path provided by -B is [dir/]stageN/,
           where N is a number in the range 0 to 9, then it will be replaced
           by [dir/]include.  This is to help with boot-strapping the com-
           piler.

       -specs=file
           Process file after the compiler reads in the standard specs file,
           in order to override the defaults that the gcc driver program uses
           when determining what switches to pass to cc1, cc1plus, as, ld,
           etc.  More than one -specs=file can be specified on the command
           line, and they are processed in order, from left to right.

       Specifying Target Machine and Compiler Version

       By default, GCC compiles code for the same type of machine that you are
       using.  However, it can also be installed as a cross-compiler, to com-
       pile for some other type of machine.  In fact, several different con-
       figurations of GCC, for different target machines, can be installed
       side by side.  Then you specify which one to use with the -b option.

       In addition, older and newer versions of GCC can be installed side by
       side.  One of them (probably the newest) will be the default, but you
       may sometimes wish to use another.

       -b machine
           The argument machine specifies the target machine for compilation.
           This is useful when you have installed GCC as a cross-compiler.

           The value to use for machine is the same as was specified as the
           machine type when configuring GCC as a cross-compiler.  For exam-
           ple, if a cross-compiler was configured with configure i386v, mean-
           ing to compile for an 80386 running System V, then you would spec-
           ify -b i386v to run that cross compiler.

           When you do not specify -b, it normally means to compile for the
           same type of machine that you are using.

       The -b and -V options actually work by controlling part of the file
       name used for the executable files and libraries used for compilation.
       A given version of GCC, for a given target machine, is normally kept in
       the directory /usr/local/lib/gcc-lib/machine/version.

       Thus, sites can customize the effect of -b or -V either by changing the
       names of these directories or adding alternate names (or symbolic
       links).  If in directory /usr/local/lib/gcc-lib/ the file 80386 is a
       link to the file i386v, then -b 80386 becomes an alias for -b i386v.

       In one respect, the -b or -V do not completely change to a different
       compiler: the top-level driver program gcc that you originally invoked
       continues to run and invoke the other executables (preprocessor, com-
       piler per se, assembler and linker) that do the real work.  However,
       since no real work is done in the driver program, it usually does not
       matter that the driver program in use is not the one for the specified
       target.  It is common for the interface to the other executables to
       change incompatibly between compiler versions, so unless the version
       specified is very close to that of the driver (for example, -V 3.0 with
       a driver program from GCC version 3.0.1), use of -V may not work; for
       example, using -V 2.95.2 will not work with a driver program from GCC
       3.0.

       The only way that the driver program depends on the target machine is
       in the parsing and handling of special machine-specific options.  How-
       ever, this is controlled by a file which is found, along with the other
       executables, in the directory for the specified version and target
       machine.  As a result, a single installed driver program adapts to any
       specified target machine, and sufficiently similar compiler versions.

       The driver program executable does control one significant thing, how-
       ever: the default version and target machine.  Therefore, you can
       install different instances of the driver program, compiled for differ-
       ent targets or versions, under different names.

       For example, if the driver for version 2.0 is installed as ogcc and
       that for version 2.1 is installed as gcc, then the command gcc will use
       version 2.1 by default, while ogcc will use 2.0 by default.  However,
       you can choose either version with either command with the -V option.

       Hardware Models and Configurations

       Earlier we discussed the standard option -b which chooses among differ-
       ent installed compilers for completely different target machines, such
       as VAX vs. 68000 vs. 80386.

       In addition, each of these target machine types can have its own spe-
       cial options, starting with -m, to choose among various hardware models
       or configurations---for example, 68010 vs 68020, floating coprocessor
       or none.  A single installed version of the compiler can compile for
       any model or configuration, according to the options specified.

       Some configurations of the compiler also support additional special
       options, usually for compatibility with other compilers on the same
       platform.

       These options are defined by the macro "TARGET_SWITCHES" in the machine

       -m68000
       -mc68000
           Generate output for a 68000.  This is the default when the compiler
           is configured for 68000-based systems.

           Use this option for microcontrollers with a 68000 or EC000 core,
           including the 68008, 68302, 68306, 68307, 68322, 68328 and 68356.

       -m68020
       -mc68020
           Generate output for a 68020.  This is the default when the compiler
           is configured for 68020-based systems.

       -m68881
           Generate output containing 68881 instructions for floating point.
           This is the default for most 68020 systems unless --nfp was speci-
           fied when the compiler was configured.

       -m68030
           Generate output for a 68030.  This is the default when the compiler
           is configured for 68030-based systems.

       -m68040
           Generate output for a 68040.  This is the default when the compiler
           is configured for 68040-based systems.

           This option inhibits the use of 68881/68882 instructions that have
           to be emulated by software on the 68040.  Use this option if your
           68040 does not have code to emulate those instructions.

       -m68060
           Generate output for a 68060.  This is the default when the compiler
           is configured for 68060-based systems.

           This option inhibits the use of 68020 and 68881/68882 instructions
           that have to be emulated by software on the 68060.  Use this option
           if your 68060 does not have code to emulate those instructions.

       -mcpu32
           Generate output for a CPU32.  This is the default when the compiler
           is configured for CPU32-based systems.

           Use this option for microcontrollers with a CPU32 or CPU32+ core,
           including the 68330, 68331, 68332, 68333, 68334, 68336, 68340,
           68341, 68349 and 68360.

       -m5200
           Generate output for a 520X ``coldfire'' family cpu.  This is the
           default when the compiler is configured for 520X-based systems.

           Use this option for microcontroller with a 5200 core, including the
           MCF5202, MCF5203, MCF5204 and MCF5202.

       -m68020-40
           Generate output for a 68040, without using any of the new instruc-
           tions.  This results in code which can run relatively efficiently

       -mfpa
           Generate output containing Sun FPA instructions for floating point.

       -msoft-float
           Generate output containing library calls for floating point.  Warn-
           ing: the requisite libraries are not available for all m68k tar-
           gets.  Normally the facilities of the machine's usual C compiler
           are used, but this can't be done directly in cross-compilation.
           You must make your own arrangements to provide suitable library
           functions for cross-compilation.  The embedded targets m68k-*-aout
           and m68k-*-coff do provide software floating point support.

       -mshort
           Consider type "int" to be 16 bits wide, like "short int".

       -mnobitfield
           Do not use the bit-field instructions.  The -m68000, -mcpu32 and
           -m5200 options imply -mnobitfield.

       -mbitfield
           Do use the bit-field instructions.  The -m68020 option implies
           -mbitfield.  This is the default if you use a configuration
           designed for a 68020.

       -mrtd
           Use a different function-calling convention, in which functions
           that take a fixed number of arguments return with the "rtd"
           instruction, which pops their arguments while returning.  This
           saves one instruction in the caller since there is no need to pop
           the arguments there.

           This calling convention is incompatible with the one normally used
           on Unix, so you cannot use it if you need to call libraries com-
           piled with the Unix compiler.

           Also, you must provide function prototypes for all functions that
           take variable numbers of arguments (including "printf"); otherwise
           incorrect code will be generated for calls to those functions.

           In addition, seriously incorrect code will result if you call a
           function with too many arguments.  (Normally, extra arguments are
           harmlessly ignored.)

           The "rtd" instruction is supported by the 68010, 68020, 68030,
           68040, 68060 and CPU32 processors, but not by the 68000 or 5200.

       -malign-int
       -mno-align-int
           Control whether GCC aligns "int", "long", "long long", "float",
           "double", and "long double" variables on a 32-bit boundary
           (-malign-int) or a 16-bit boundary (-mno-align-int).  Aligning
           variables on 32-bit boundaries produces code that runs somewhat
           faster on processors with 32-bit busses at the expense of more mem-
           ory.

           Warning: if you use the -malign-int switch, GCC will align struc-
           tures containing the above types  differently than most published

       -mno-strict-align
       -mstrict-align
           Do not (do) assume that unaligned memory references will be handled
           by the system.

       M68hc1x Options

       These are the -m options defined for the 68hc11 and 68hc12 microcon-
       trollers.  The default values for these options depends on which style
       of microcontroller was selected when the compiler was configured; the
       defaults for the most common choices are given below.

       -m6811
       -m68hc11
           Generate output for a 68HC11.  This is the default when the com-
           piler is configured for 68HC11-based systems.

       -m6812
       -m68hc12
           Generate output for a 68HC12.  This is the default when the com-
           piler is configured for 68HC12-based systems.

       -mauto-incdec
           Enable the use of 68HC12 pre and post auto-increment and auto-
           decrement addressing modes.

       -mshort
           Consider type "int" to be 16 bits wide, like "short int".

       -msoft-reg-count=count
           Specify the number of pseudo-soft registers which are used for the
           code generation.  The maximum number is 32.  Using more pseudo-soft
           register may or may not result in better code depending on the pro-
           gram.  The default is 4 for 68HC11 and 2 for 68HC12.

       VAX Options

       These -m options are defined for the VAX:

       -munix
           Do not output certain jump instructions ("aobleq" and so on) that
           the Unix assembler for the VAX cannot handle across long ranges.

       -mgnu
           Do output those jump instructions, on the assumption that you will
           assemble with the GNU assembler.

       -mg Output code for g-format floating point numbers instead of d-for-
           mat.

       SPARC Options

       These -m switches are supported on the SPARC:

       -mno-app-regs
       -mapp-regs
           Specify -mapp-regs to generate output using the global registers 2
           Generate output containing floating point instructions.  This is
           the default.

       -mno-fpu
       -msoft-float
           Generate output containing library calls for floating point.  Warn-
           ing: the requisite libraries are not available for all SPARC tar-
           gets.  Normally the facilities of the machine's usual C compiler
           are used, but this cannot be done directly in cross-compilation.
           You must make your own arrangements to provide suitable library
           functions for cross-compilation.  The embedded targets sparc-*-aout
           and sparclite-*-* do provide software floating point support.

           -msoft-float changes the calling convention in the output file;
           therefore, it is only useful if you compile all of a program with
           this option.  In particular, you need to compile libgcc.a, the
           library that comes with GCC, with -msoft-float in order for this to
           work.

       -mhard-quad-float
           Generate output containing quad-word (long double) floating point
           instructions.

       -msoft-quad-float
           Generate output containing library calls for quad-word (long dou-
           ble) floating point instructions.  The functions called are those
           specified in the SPARC ABI.  This is the default.

           As of this writing, there are no sparc implementations that have
           hardware support for the quad-word floating point instructions.
           They all invoke a trap handler for one of these instructions, and
           then the trap handler emulates the effect of the instruction.
           Because of the trap handler overhead, this is much slower than
           calling the ABI library routines.  Thus the -msoft-quad-float
           option is the default.

       -mno-flat
       -mflat
           With -mflat, the compiler does not generate save/restore instruc-
           tions and will use a ``flat'' or single register window calling
           convention.  This model uses %i7 as the frame pointer and is com-
           patible with the normal register window model.  Code from either
           may be intermixed.  The local registers and the input registers
           (0--5) are still treated as ``call saved'' registers and will be
           saved on the stack as necessary.

           With -mno-flat (the default), the compiler emits save/restore
           instructions (except for leaf functions) and is the normal mode of
           operation.

       -mno-unaligned-doubles
       -munaligned-doubles
           Assume that doubles have 8 byte alignment.  This is the default.

           With -munaligned-doubles, GCC assumes that doubles have 8 byte
           alignment only if they are contained in another type, or if they
           have an absolute address.  Otherwise, it assumes they have 4 byte
           "std" instructions for copies in structure assignment, in place of
           twice as many "ld" and "st" pairs.  However, the use of this
           changed alignment directly violates the Sparc ABI.  Thus, it's
           intended only for use on targets where the developer acknowledges
           that their resulting code will not be directly in line with the
           rules of the ABI.

       -mv8
       -msparclite
           These two options select variations on the SPARC architecture.

           By default (unless specifically configured for the Fujitsu SPAR-
           Clite), GCC generates code for the v7 variant of the SPARC archi-
           tecture.

           -mv8 will give you SPARC v8 code.  The only difference from v7 code
           is that the compiler emits the integer multiply and integer divide
           instructions which exist in SPARC v8 but not in SPARC v7.

           -msparclite will give you SPARClite code.  This adds the integer
           multiply, integer divide step and scan ("ffs") instructions which
           exist in SPARClite but not in SPARC v7.

           These options are deprecated and will be deleted in a future GCC
           release.  They have been replaced with -mcpu=xxx.

       -mcypress
       -msupersparc
           These two options select the processor for which the code is opti-
           mized.

           With -mcypress (the default), the compiler optimizes code for the
           Cypress CY7C602 chip, as used in the SparcStation/SparcServer 3xx
           series.  This is also appropriate for the older SparcStation 1, 2,
           IPX etc.

           With -msupersparc the compiler optimizes code for the SuperSparc
           cpu, as used in the SparcStation 10, 1000 and 2000 series.  This
           flag also enables use of the full SPARC v8 instruction set.

           These options are deprecated and will be deleted in a future GCC
           release.  They have been replaced with -mcpu=xxx.

       -mcpu=cpu_type
           Set the instruction set, register set, and instruction scheduling
           parameters for machine type cpu_type.  Supported values for
           cpu_type are v7, cypress, v8, supersparc, sparclite, hypersparc,
           sparclite86x, f930, f934, sparclet, tsc701, v9, and ultrasparc.

           Default instruction scheduling parameters are used for values that
           select an architecture and not an implementation.  These are v7,
           v8, sparclite, sparclet, v9.

           Here is a list of each supported architecture and their supported
           implementations.

                       v7:             cypress

           The same values for -mcpu=cpu_type can be used for -mtune=cpu_type,
           but the only useful values are those that select a particular cpu
           implementation.  Those are cypress, supersparc, hypersparc, f930,
           f934, sparclite86x, tsc701, and ultrasparc.

       These -m switches are supported in addition to the above on the SPAR-
       CLET processor.

       -mlittle-endian
           Generate code for a processor running in little-endian mode.

       -mlive-g0
           Treat register %g0 as a normal register.  GCC will continue to
           clobber it as necessary but will not assume it always reads as 0.

       -mbroken-saverestore
           Generate code that does not use non-trivial forms of the "save" and
           "restore" instructions.  Early versions of the SPARCLET processor
           do not correctly handle "save" and "restore" instructions used with
           arguments.  They correctly handle them used without arguments.  A
           "save" instruction used without arguments increments the current
           window pointer but does not allocate a new stack frame.  It is
           assumed that the window overflow trap handler will properly handle
           this case as will interrupt handlers.

       These -m switches are supported in addition to the above on SPARC V9
       processors in 64-bit environments.

       -mlittle-endian
           Generate code for a processor running in little-endian mode.

       -m32
       -m64
           Generate code for a 32-bit or 64-bit environment.  The 32-bit envi-
           ronment sets int, long and pointer to 32 bits.  The 64-bit environ-
           ment sets int to 32 bits and long and pointer to 64 bits.

       -mcmodel=medlow
           Generate code for the Medium/Low code model: the program must be
           linked in the low 32 bits of the address space.  Pointers are 64
           bits.  Programs can be statically or dynamically linked.

       -mcmodel=medmid
           Generate code for the Medium/Middle code model: the program must be
           linked in the low 44 bits of the address space, the text segment
           must be less than 2G bytes, and data segment must be within 2G of
           the text segment.  Pointers are 64 bits.

       -mcmodel=medany
           Generate code for the Medium/Anywhere code model: the program may
           be linked anywhere in the address space, the text segment must be
           less than 2G bytes, and data segment must be within 2G of the text
           segment.  Pointers are 64 bits.

       -mcmodel=embmedany
           Generate code for the Medium/Anywhere code model for embedded sys-
           when making stack frame references.  Otherwise, assume no such off-
           set is present.

       Convex Options

       These -m options are defined for Convex:

       -mc1
           Generate output for C1.  The code will run on any Convex machine.
           The preprocessor symbol "__convex__c1__" is defined.

       -mc2
           Generate output for C2.  Uses instructions not available on C1.
           Scheduling and other optimizations are chosen for max performance
           on C2.  The preprocessor symbol "__convex_c2__" is defined.

       -mc32
           Generate output for C32xx.  Uses instructions not available on C1.
           Scheduling and other optimizations are chosen for max performance
           on C32.  The preprocessor symbol "__convex_c32__" is defined.

       -mc34
           Generate output for C34xx.  Uses instructions not available on C1.
           Scheduling and other optimizations are chosen for max performance
           on C34.  The preprocessor symbol "__convex_c34__" is defined.

       -mc38
           Generate output for C38xx.  Uses instructions not available on C1.
           Scheduling and other optimizations are chosen for max performance
           on C38.  The preprocessor symbol "__convex_c38__" is defined.

       -margcount
           Generate code which puts an argument count in the word preceding
           each argument list.  This is compatible with regular CC, and a few
           programs may need the argument count word.  GDB and other source-
           level debuggers do not need it; this info is in the symbol table.

       -mnoargcount
           Omit the argument count word.  This is the default.

       -mvolatile-cache
           Allow volatile references to be cached.  This is the default.

       -mvolatile-nocache
           Volatile references bypass the data cache, going all the way to
           memory.  This is only needed for multi-processor code that does not
           use standard synchronization instructions.  Making non-volatile
           references to volatile locations will not necessarily work.

       -mlong32
           Type long is 32 bits, the same as type int.  This is the default.

       -mlong64
           Type long is 64 bits, the same as type long long.  This option is
           useless, because no library support exists for it.

       AMD29K Options
           Generate code that assumes the "DW" bit is not set.

       -mbw
           Generate code that assumes the system supports byte and halfword
           write operations.  This is the default.

       -mnbw
           Generate code that assumes the systems does not support byte and
           halfword write operations.  -mnbw implies -mndw.

       -msmall
           Use a small memory model that assumes that all function addresses
           are either within a single 256 KB segment or at an absolute address
           of less than 256k.  This allows the "call" instruction to be used
           instead of a "const", "consth", "calli" sequence.

       -mnormal
           Use the normal memory model: Generate "call" instructions only when
           calling functions in the same file and "calli" instructions other-
           wise.  This works if each file occupies less than 256 KB but allows
           the entire executable to be larger than 256 KB.  This is the
           default.

       -mlarge
           Always use "calli" instructions.  Specify this option if you expect
           a single file to compile into more than 256 KB of code.

       -m29050
           Generate code for the Am29050.

       -m29000
           Generate code for the Am29000.  This is the default.

       -mkernel-registers
           Generate references to registers "gr64-gr95" instead of to regis-
           ters "gr96-gr127".  This option can be used when compiling kernel
           code that wants a set of global registers disjoint from that used
           by user-mode code.

           Note that when this option is used, register names in -f flags must
           use the normal, user-mode, names.

       -muser-registers
           Use the normal set of global registers, "gr96-gr127".  This is the
           default.

       -mstack-check
       -mno-stack-check
           Insert (or do not insert) a call to "__msp_check" after each stack
           adjustment.  This is often used for kernel code.

       -mstorem-bug
       -mno-storem-bug
           -mstorem-bug handles 29k processors which cannot handle the separa-
           tion of a mtsrim insn and a storem instruction (most 29000 chips to
           date, but not the 29050).

           not pass -assert pure-text to the linker when linking a shared
           object.

       -msoft-float
           Generate output containing library calls for floating point.  Warn-
           ing: the requisite libraries are not part of GCC.  Normally the
           facilities of the machine's usual C compiler are used, but this
           can't be done directly in cross-compilation.  You must make your
           own arrangements to provide suitable library functions for
           cross-compilation.

       -mno-multm
           Do not generate multm or multmu instructions.  This is useful for
           some embedded systems which do not have trap handlers for these
           instructions.

       ARM Options

       These -m options are defined for Advanced RISC Machines (ARM) architec-
       tures:

       -mapcs-frame
           Generate a stack frame that is compliant with the ARM Procedure
           Call Standard for all functions, even if this is not strictly nec-
           essary for correct execution of the code.  Specifying
           -fomit-frame-pointer with this option will cause the stack frames
           not to be generated for leaf functions.  The default is
           -mno-apcs-frame.

       -mapcs
           This is a synonym for -mapcs-frame.

       -mapcs-26
           Generate code for a processor running with a 26-bit program
           counter, and conforming to the function calling standards for the
           APCS 26-bit option.  This option replaces the -m2 and -m3 options
           of previous releases of the compiler.

       -mapcs-32
           Generate code for a processor running with a 32-bit program
           counter, and conforming to the function calling standards for the
           APCS 32-bit option.  This option replaces the -m6 option of previ-
           ous releases of the compiler.

       -mthumb-interwork
           Generate code which supports calling between the ARM and Thumb
           instruction sets.  Without this option the two instruction sets
           cannot be reliably used inside one program.  The default is
           -mno-thumb-interwork, since slightly larger code is generated when
           -mthumb-interwork is specified.

       -mno-sched-prolog
           Prevent the reordering of instructions in the function prolog, or
           the merging of those instruction with the instructions in the func-
           tion's body.  This means that all functions will start with a rec-
           ognizable set of instructions (or in fact one of a choice from a
           small set of different function prologues), and this information
           ing: the requisite libraries are not available for all ARM targets.
           Normally the facilities of the machine's usual C compiler are used,
           but this cannot be done directly in cross-compilation.  You must
           make your own arrangements to provide suitable library functions
           for cross-compilation.

           -msoft-float changes the calling convention in the output file;
           therefore, it is only useful if you compile all of a program with
           this option.  In particular, you need to compile libgcc.a, the
           library that comes with GCC, with -msoft-float in order for this to
           work.

       -mlittle-endian
           Generate code for a processor running in little-endian mode.  This
           is the default for all standard configurations.

       -mbig-endian
           Generate code for a processor running in big-endian mode; the
           default is to compile code for a little-endian processor.

       -mwords-little-endian
           This option only applies when generating code for big-endian pro-
           cessors.  Generate code for a little-endian word order but a big-
           endian byte order.  That is, a byte order of the form 32107654.
           Note: this option should only be used if you require compatibility
           with code for big-endian ARM processors generated by versions of
           the compiler prior to 2.8.

       -malignment-traps
           Generate code that will not trap if the MMU has alignment traps
           enabled.  On ARM architectures prior to ARMv4, there were no
           instructions to access half-word objects stored in memory.  How-
           ever, when reading from memory a feature of the ARM architecture
           allows a word load to be used, even if the address is unaligned,
           and the processor core will rotate the data as it is being loaded.
           This option tells the compiler that such misaligned accesses will
           cause a MMU trap and that it should instead synthesise the access
           as a series of byte accesses.  The compiler can still use word
           accesses to load half-word data if it knows that the address is
           aligned to a word boundary.

           This option is ignored when compiling for ARM architecture 4 or
           later, since these processors have instructions to directly access
           half-word objects in memory.

       -mno-alignment-traps
           Generate code that assumes that the MMU will not trap unaligned
           accesses.  This produces better code when the target instruction
           set does not have half-word memory operations (i.e. implementations
           prior to ARMv4).

           Note that you cannot use this option to access unaligned word
           objects, since the processor will only fetch one 32-bit aligned
           object from memory.

           The default setting for most targets is -mno-alignment-traps, since
           this produces better code when there are no half-word memory

       -mbsd
           This option only applies to RISC iX.  Emulate the native BSD-mode
           compiler.  This is the default if -ansi is not specified.

       -mxopen
           This option only applies to RISC iX.  Emulate the native
           X/Open-mode compiler.

       -mno-symrename
           This option only applies to RISC iX.  Do not run the assembler
           post-processor, symrename, after code has been assembled.  Normally
           it is necessary to modify some of the standard symbols in prepara-
           tion for linking with the RISC iX C library; this option suppresses
           this pass.  The post-processor is never run when the compiler is
           built for cross-compilation.

       -mcpu=name
           This specifies the name of the target ARM processor.  GCC uses this
           name to determine what kind of instructions it can emit when gener-
           ating assembly code.  Permissible names are: arm2, arm250, arm3,
           arm6, arm60, arm600, arm610, arm620, arm7, arm7m, arm7d, arm7dm,
           arm7di, arm7dmi, arm70, arm700, arm700i, arm710, arm710c, arm7100,
           arm7500, arm7500fe, arm7tdmi, arm8, strongarm, strongarm110, stron-
           garm1100, arm8, arm810, arm9, arm9e, arm920, arm920t, arm940t,
           arm9tdmi, arm10tdmi, arm1020t, xscale.

       -mtune=name
           This option is very similar to the -mcpu= option, except that
           instead of specifying the actual target processor type, and hence
           restricting which instructions can be used, it specifies that GCC
           should tune the performance of the code as if the target were of
           the type specified in this option, but still choosing the instruc-
           tions that it will generate based on the cpu specified by a -mcpu=
           option.  For some ARM implementations better performance can be
           obtained by using this option.

       -march=name
           This specifies the name of the target ARM architecture.  GCC uses
           this name to determine what kind of instructions it can emit when
           generating assembly code.  This option can be used in conjunction
           with or instead of the -mcpu= option.  Permissible names are:
           armv2, armv2a, armv3, armv3m, armv4, armv4t, armv5, armv5t,
           armv5te.

       -mfpe=number
       -mfp=number
           This specifies the version of the floating point emulation avail-
           able on the target.  Permissible values are 2 and 3.  -mfp= is a
           synonym for -mfpe=, for compatibility with older versions of GCC.

       -mstructure-size-boundary=n
           The size of all structures and unions will be rounded up to a mul-
           tiple of the number of bits set by this option.  Permissible values
           are 8 and 32.  The default value varies for different toolchains.
           For the COFF targeted toolchain the default value is 8.  Specifying
           the larger number can produce faster, more efficient code, but can

       -mlong-calls
       -mno-long-calls
           Tells the compiler to perform function calls by first loading the
           address of the function into a register and then performing a sub-
           routine call on this register.  This switch is needed if the target
           function will lie outside of the 64 megabyte addressing range of
           the offset based version of subroutine call instruction.

           Even if this switch is enabled, not all function calls will be
           turned into long calls.  The heuristic is that static functions,
           functions which have the short-call attribute, functions that are
           inside the scope of a #pragma no_long_calls directive and functions
           whose definitions have already been compiled within the current
           compilation unit, will not be turned into long calls.  The excep-
           tion to this rule is that weak function definitions, functions with
           the long-call attribute or the section attribute, and functions
           that are within the scope of a #pragma long_calls directive, will
           always be turned into long calls.

           This feature is not enabled by default.  Specifying -mno-long-calls
           will restore the default behavior, as will placing the function
           calls within the scope of a #pragma long_calls_off directive.  Note
           these switches have no effect on how the compiler generates code to
           handle function calls via function pointers.

       -mnop-fun-dllimport
           Disable support for the "dllimport" attribute.

       -msingle-pic-base
           Treat the register used for PIC addressing as read-only, rather
           than loading it in the prologue for each function.  The run-time
           system is responsible for initializing this register with an appro-
           priate value before execution begins.

       -mpic-register=reg
           Specify the register to be used for PIC addressing.  The default is
           R10 unless stack-checking is enabled, when R9 is used.

       -mpoke-function-name
           Write the name of each function into the text section, directly
           preceding the function prologue.  The generated code is similar to
           this:

                        t0
                            .ascii "arm_poke_function_name", 0
                            .align
                        t1
                            .word 0xff000000 + (t1 - t0)
                        arm_poke_function_name
                            mov     ip, sp
                            stmfd   sp!, {fp, ip, lr, pc}
                            sub     fp, ip, #4

           When performing a stack backtrace, code can inspect the value of
           "pc" stored at "fp + 0".  If the trace function then looks at loca-
           tion "pc - 12" and the top 8 bits are set, then we know that there
           is a function name embedded immediately preceding this location and
           that does not call any other functions.)  The default is
           -mno-tpcs-frame.

       -mtpcs-leaf-frame
           Generate a stack frame that is compliant with the Thumb Procedure
           Call Standard for all leaf functions.  (A leaf function is one that
           does not call any other functions.)  The default is
           -mno-apcs-leaf-frame.

       -mcallee-super-interworking
           Gives all externally visible functions in the file being compiled
           an ARM instruction set header which switches to Thumb mode before
           executing the rest of the function.  This allows these functions to
           be called from non-interworking code.

       -mcaller-super-interworking
           Allows calls via function pointers (including virtual functions) to
           execute correctly regardless of whether the target code has been
           compiled for interworking or not.  There is a small overhead in the
           cost of executing a function pointer if this option is enabled.

       MN10200 Options

       These -m options are defined for Matsushita MN10200 architectures:

       -mrelax
           Indicate to the linker that it should perform a relaxation opti-
           mization pass to shorten branches, calls and absolute memory
           addresses.  This option only has an effect when used on the command
           line for the final link step.

           This option makes symbolic debugging impossible.

       MN10300 Options

       These -m options are defined for Matsushita MN10300 architectures:

       -mmult-bug
           Generate code to avoid bugs in the multiply instructions for the
           MN10300 processors.  This is the default.

       -mno-mult-bug
           Do not generate code to avoid bugs in the multiply instructions for
           the MN10300 processors.

       -mam33
           Generate code which uses features specific to the AM33 processor.

       -mno-am33
           Do not generate code which uses features specific to the AM33 pro-
           cessor.  This is the default.

       -mno-crt0
           Do not link in the C run-time initialization object file.

       -mrelax
           Indicate to the linker that it should perform a relaxation opti-

       -m32rx
           Generate code for the M32R/X.

       -m32r
           Generate code for the M32R.  This is the default.

       -mcode-model=small
           Assume all objects live in the lower 16MB of memory (so that their
           addresses can be loaded with the "ld24" instruction), and assume
           all subroutines are reachable with the "bl" instruction.  This is
           the default.

           The addressability of a particular object can be set with the
           "model" attribute.

       -mcode-model=medium
           Assume objects may be anywhere in the 32-bit address space (the
           compiler will generate "seth/add3" instructions to load their
           addresses), and assume all subroutines are reachable with the "bl"
           instruction.

       -mcode-model=large
           Assume objects may be anywhere in the 32-bit address space (the
           compiler will generate "seth/add3" instructions to load their
           addresses), and assume subroutines may not be reachable with the
           "bl" instruction (the compiler will generate the much slower
           "seth/add3/jl" instruction sequence).

       -msdata=none
           Disable use of the small data area.  Variables will be put into one
           of .data, bss, or .rodata (unless the "section" attribute has been
           specified).  This is the default.

           The small data area consists of sections .sdata and .sbss.  Objects
           may be explicitly put in the small data area with the "section"
           attribute using one of these sections.

       -msdata=sdata
           Put small global and static data in the small data area, but do not
           generate special code to reference them.

       -msdata=use
           Put small global and static data in the small data area, and gener-
           ate special instructions to reference them.

       -G num
           Put global and static objects less than or equal to num bytes into
           the small data or bss sections instead of the normal data or bss
           sections.  The default value of num is 8.  The -msdata option must
           be set to one of sdata or use for this option to have any effect.

           All modules should be compiled with the same -G num value.  Compil-
           ing with different values of num may or may not work; if it doesn't
           the linker will give an error message---incorrect code will not be
           generated.

           the m88110.

       -m88110
           Generate code that works best for the m88110, and may not run on
           the m88100.

       -mbig-pic
           Obsolete option to be removed from the next revision.  Use -fPIC.

       -midentify-revision
           Include an "ident" directive in the assembler output recording the
           source file name, compiler name and version, timestamp, and compi-
           lation flags used.

       -mno-underscores
           In assembler output, emit symbol names without adding an underscore
           character at the beginning of each name.  The default is to use an
           underscore as prefix on each name.

       -mocs-debug-info
       -mno-ocs-debug-info
           Include (or omit) additional debugging information (about registers
           used in each stack frame) as specified in the 88open Object Compat-
           ibility Standard, ``OCS''.  This extra information allows debugging
           of code that has had the frame pointer eliminated.  The default for
           DG/UX, SVr4, and Delta 88 SVr3.2 is to include this information;
           other 88k configurations omit this information by default.

       -mocs-frame-position
           When emitting COFF debugging information for automatic variables
           and parameters stored on the stack, use the offset from the canoni-
           cal frame address, which is the stack pointer (register 31) on
           entry to the function.  The DG/UX, SVr4, Delta88 SVr3.2, and BCS
           configurations use -mocs-frame-position; other 88k configurations
           have the default -mno-ocs-frame-position.

       -mno-ocs-frame-position
           When emitting COFF debugging information for automatic variables
           and parameters stored on the stack, use the offset from the frame
           pointer register (register 30).  When this option is in effect, the
           frame pointer is not eliminated when debugging information is
           selected by the -g switch.

       -moptimize-arg-area
           Save space by reorganizing the stack frame.  This option generates
           code that does not agree with the 88open specifications, but uses
           less memory.

       -mno-optimize-arg-area
           Do not reorganize the stack frame to save space.  This is the
           default.  The generated conforms to the specification, but uses
           more memory.

       -mshort-data-num
           Generate smaller data references by making them relative to "r0",
           which allows loading a value using a single instruction (rather
           than the usual two).  You control which data references are

           The order of memory references made by the MC88110 processor does
           not always match the order of the instructions requesting those
           references.  In particular, a load instruction may execute before a
           preceding store instruction.  Such reordering violates sequential
           consistency of volatile memory references, when there are multiple
           processors.   When consistency must be guaranteed, GCC generates
           special instructions, as needed, to force execution in the proper
           order.

           The MC88100 processor does not reorder memory references and so
           always provides sequential consistency.  However, by default, GCC
           generates the special instructions to guarantee consistency even
           when you use -m88100, so that the code may be run on an MC88110
           processor.  If you intend to run your code only on the MC88100 pro-
           cessor, you may use -mno-serialize-volatile.

           The extra code generated to guarantee consistency may affect the
           performance of your application.  If you know that you can safely
           forgo this guarantee, you may use -mno-serialize-volatile.

       -msvr4
       -msvr3
           Turn on (-msvr4) or off (-msvr3) compiler extensions related to
           System V release 4 (SVr4).  This controls the following:

           1.  Which variant of the assembler syntax to emit.

           2.  -msvr4 makes the C preprocessor recognize #pragma weak that is
               used on System V release 4.

           3.  -msvr4 makes GCC issue additional declaration directives used
               in SVr4.

           -msvr4 is the default for the m88k-motorola-sysv4 and m88k-dg-dgux
           m88k configurations.  -msvr3 is the default for all other m88k con-
           figurations.

       -mversion-03.00
           This option is obsolete, and is ignored.

       -mno-check-zero-division
       -mcheck-zero-division
           Do, or don't, generate code to guarantee that integer division by
           zero will be detected.  By default, detection is guaranteed.

           Some models of the MC88100 processor fail to trap upon integer
           division by zero under certain conditions.  By default, when com-
           piling code that might be run on such a processor, GCC generates
           code that explicitly checks for zero-valued divisors and traps with
           exception number 503 when one is detected.  Use of
           -mno-check-zero-division suppresses such checking for code gener-
           ated to run on an MC88100 processor.

           GCC assumes that the MC88110 processor correctly detects all
           instances of integer division by zero.  When -m88110 is specified,
           no explicit checks for zero-valued divisors are generated, and both
           large cost in execution time.  By default, when compiling code that
           might be run on an MC88100 processor, GCC emulates signed integer
           division using the unsigned integer division instruction divu),
           thereby avoiding the large penalty of a trap to the operating sys-
           tem.  Such emulation has its own, smaller, execution cost in both
           time and space.  To the extent that your code's important signed
           integer division operations are performed on two nonnegative
           operands, it may be desirable to use the div instruction directly.

           On the MC88110 processor the div instruction (also known as the
           divs instruction) processes negative operands without trapping to
           the operating system.  When -m88110 is specified,
           -muse-div-instruction is ignored, and the div instruction is used
           for signed integer division.

           Note that the result of dividing "INT_MIN" by -1 is undefined.  In
           particular, the behavior of such a division with and without
           -muse-div-instruction may differ.

       -mtrap-large-shift
       -mhandle-large-shift
           Include code to detect bit-shifts of more than 31 bits; respec-
           tively, trap such shifts or emit code to handle them properly.  By
           default GCC makes no special provision for large bit shifts.

       -mwarn-passed-structs
           Warn when a function passes a struct as an argument or result.
           Structure-passing conventions have changed during the evolution of
           the C language, and are often the source of portability problems.
           By default, GCC issues no such warning.

       IBM RS/6000 and PowerPC Options

       These -m options are defined for the IBM RS/6000 and PowerPC:

       -mpower
       -mno-power
       -mpower2
       -mno-power2
       -mpowerpc
       -mno-powerpc
       -mpowerpc-gpopt
       -mno-powerpc-gpopt
       -mpowerpc-gfxopt
       -mno-powerpc-gfxopt
       -mpowerpc64
       -mno-powerpc64
           GCC supports two related instruction set architectures for the
           RS/6000 and PowerPC.  The POWER instruction set are those
           instructions supported by the rios chip set used in the original
           RS/6000 systems and the PowerPC instruction set is the architecture
           of the Motorola MPC5xx, MPC6xx, MPC8xx microprocessors, and the IBM
           4xx microprocessors.

           Neither architecture is a subset of the other.  However there is a
           large common subset of instructions supported by both.  An MQ reg-
           ister is included in processors supporting the POWER architecture.
           Specifying -mpower2 implies -power and also allows GCC to generate
           instructions that are present in the POWER2 architecture but not
           the original POWER architecture.

           The -mpowerpc option allows GCC to generate instructions that are
           found only in the 32-bit subset of the PowerPC architecture.  Spec-
           ifying -mpowerpc-gpopt implies -mpowerpc and also allows GCC to use
           the optional PowerPC architecture instructions in the General Pur-
           pose group, including floating-point square root.  Specifying
           -mpowerpc-gfxopt implies -mpowerpc and also allows GCC to use the
           optional PowerPC architecture instructions in the Graphics group,
           including floating-point select.

           The -mpowerpc64 option allows GCC to generate the additional 64-bit
           instructions that are found in the full PowerPC64 architecture and
           to treat GPRs as 64-bit, doubleword quantities.  GCC defaults to
           -mno-powerpc64.

           If you specify both -mno-power and -mno-powerpc, GCC will use only
           the instructions in the common subset of both architectures plus
           some special AIX common-mode calls, and will not use the MQ regis-
           ter.  Specifying both -mpower and -mpowerpc permits GCC to use any
           instruction from either architecture and to allow use of the MQ
           register; specify this for the Motorola MPC601.

       -mnew-mnemonics
       -mold-mnemonics
           Select which mnemonics to use in the generated assembler code.
           With -mnew-mnemonics, GCC uses the assembler mnemonics defined for
           the PowerPC architecture.  With -mold-mnemonics it uses the assem-
           bler mnemonics defined for the POWER architecture.  Instructions
           defined in only one architecture have only one mnemonic; GCC uses
           that mnemonic irrespective of which of these options is specified.

           GCC defaults to the mnemonics appropriate for the architecture in
           use.  Specifying -mcpu=cpu_type sometimes overrides the value of
           these option.  Unless you are building a cross-compiler, you should
           normally not specify either -mnew-mnemonics or -mold-mnemonics, but
           should instead accept the default.

       -mcpu=cpu_type
           Set architecture type, register usage, choice of mnemonics, and
           instruction scheduling parameters for machine type cpu_type.  Sup-
           ported values for cpu_type are rios, rios1, rsc, rios2, rs64a, 601,
           602, 603, 603e, 604, 604e, 620, 630, 740, 7400, 7450, 750, power,
           power2, powerpc, 403, 505, 801, 821, 823, and 860 and common.

           -mcpu=common selects a completely generic processor.  Code gener-
           ated under this option will run on any POWER or PowerPC processor.
           GCC will use only the instructions in the common subset of both
           architectures, and will not use the MQ register.  GCC assumes a
           generic processor model for scheduling purposes.

           -mcpu=power, -mcpu=power2, -mcpu=powerpc, and -mcpu=powerpc64 spec-
           ify generic POWER, POWER2, pure 32-bit PowerPC (i.e., not MPC601),
           and 64-bit PowerPC architecture machine types, with an appropriate,
           generic processor model assumed for scheduling purposes.
               -mno-power, -mno-powerc

           power
           power2
           rios1
           rios2
           rsc -mpower, -mno-powerpc, -mno-new-mnemonics

           powerpc
           rs64a
           602
           603
           603e
           604
           620
           630
           740
           7400
           7450
           750
           505 -mno-power, -mpowerpc, -mnew-mnemonics

           601 -mpower, -mpowerpc, -mnew-mnemonics

           403
           821
           860 -mno-power, -mpowerpc, -mnew-mnemonics, -msoft-float

       -mtune=cpu_type
           Set the instruction scheduling parameters for machine type
           cpu_type, but do not set the architecture type, register usage, or
           choice of mnemonics, as -mcpu=cpu_type would.  The same values for
           cpu_type are used for -mtune as for -mcpu.  If both are specified,
           the code generated will use the architecture, registers, and
           mnemonics set by -mcpu, but the scheduling parameters set by
           -mtune.

       -maltivec
       -mno-altivec
           These switches enable or disable the use of built-in functions that
           allow access to the AltiVec instruction set.  You may also need to
           set -mabi=altivec to adjust the current ABI with AltiVec ABI
           enhancements.

       -mfull-toc
       -mno-fp-in-toc
       -mno-sum-in-toc
       -mminimal-toc
           Modify generation of the TOC (Table Of Contents), which is created
           for every executable file.  The -mfull-toc option is selected by
           default.  In that case, GCC will allocate at least one TOC entry
           for each unique non-automatic variable reference in your program.
           GCC will also place floating-point constants in the TOC.  However,
           only 16,384 entries are available in the TOC.

           If you receive a linker error message that saying you have over-
           flowed the available TOC space, you can reduce the amount of TOC
           of these options, specify -mminimal-toc instead.  This option
           causes GCC to make only one TOC entry for every file.  When you
           specify this option, GCC will produce code that is slower and
           larger but which uses extremely little TOC space.  You may wish to
           use this option only on files that contain less frequently executed
           code.

       -maix64
       -maix32
           Enable 64-bit AIX ABI and calling convention: 64-bit pointers,
           64-bit "long" type, and the infrastructure needed to support them.
           Specifying -maix64 implies -mpowerpc64 and -mpowerpc, while -maix32
           disables the 64-bit ABI and implies -mno-powerpc64.  GCC defaults
           to -maix32.

       -mxl-call
       -mno-xl-call
           On AIX, pass floating-point arguments to prototyped functions
           beyond the register save area (RSA) on the stack in addition to
           argument FPRs.  The AIX calling convention was extended but not
           initially documented to handle an obscure K&R C case of calling a
           function that takes the address of its arguments with fewer argu-
           ments than declared.  AIX XL compilers access floating point argu-
           ments which do not fit in the RSA from the stack when a subroutine
           is compiled without optimization.  Because always storing floating-
           point arguments on the stack is inefficient and rarely needed, this
           option is not enabled by default and only is necessary when calling
           subroutines compiled by AIX XL compilers without optimization.

       -mpe
           Support IBM RS/6000 SP Parallel Environment (PE).  Link an applica-
           tion written to use message passing with special startup code to
           enable the application to run.  The system must have PE installed
           in the standard location (/usr/lpp/ppe.poe/), or the specs file
           must be overridden with the -specs= option to specify the appropri-
           ate directory location.  The Parallel Environment does not support
           threads, so the -mpe option and the -pthread option are incompati-
           ble.

       -msoft-float
       -mhard-float
           Generate code that does not use (uses) the floating-point register
           set.  Software floating point emulation is provided if you use the
           -msoft-float option, and pass the option to GCC when linking.

       -mmultiple
       -mno-multiple
           Generate code that uses (does not use) the load multiple word
           instructions and the store multiple word instructions.  These
           instructions are generated by default on POWER systems, and not
           generated on PowerPC systems.  Do not use -mmultiple on little
           endian PowerPC systems, since those instructions do not work when
           the processor is in little endian mode.  The exceptions are PPC740
           and PPC750 which permit the instructions usage in little endian
           mode.

       -mstring

       -mupdate
       -mno-update
           Generate code that uses (does not use) the load or store instruc-
           tions that update the base register to the address of the calcu-
           lated memory location.  These instructions are generated by
           default.  If you use -mno-update, there is a small window between
           the time that the stack pointer is updated and the address of the
           previous frame is stored, which means code that walks the stack
           frame across interrupts or signals may get corrupted data.

       -mfused-madd
       -mno-fused-madd
           Generate code that uses (does not use) the floating point multiply
           and accumulate instructions.  These instructions are generated by
           default if hardware floating is used.

       -mno-bit-align
       -mbit-align
           On System V.4 and embedded PowerPC systems do not (do) force struc-
           tures and unions that contain bit-fields to be aligned to the base
           type of the bit-field.

           For example, by default a structure containing nothing but 8
           "unsigned" bit-fields of length 1 would be aligned to a 4 byte
           boundary and have a size of 4 bytes.  By using -mno-bit-align, the
           structure would be aligned to a 1 byte boundary and be one byte in
           size.

       -mno-strict-align
       -mstrict-align
           On System V.4 and embedded PowerPC systems do not (do) assume that
           unaligned memory references will be handled by the system.

       -mrelocatable
       -mno-relocatable
           On embedded PowerPC systems generate code that allows (does not
           allow) the program to be relocated to a different address at run-
           time.  If you use -mrelocatable on any module, all objects linked
           together must be compiled with -mrelocatable or -mrelocatable-lib.

       -mrelocatable-lib
       -mno-relocatable-lib
           On embedded PowerPC systems generate code that allows (does not
           allow) the program to be relocated to a different address at run-
           time.  Modules compiled with -mrelocatable-lib can be linked with
           either modules compiled without -mrelocatable and -mrelocatable-lib
           or with modules compiled with the -mrelocatable options.

       -mno-toc
       -mtoc
           On System V.4 and embedded PowerPC systems do not (do) assume that
           register 2 contains a pointer to a global area pointing to the
           addresses used in the program.

       -mlittle
       -mlittle-endian

       -mcall-sysv
           On System V.4 and embedded PowerPC systems compile code using call-
           ing conventions that adheres to the March 1995 draft of the System
           V Application Binary Interface, PowerPC processor supplement.  This
           is the default unless you configured GCC using powerpc-*-eabiaix.

       -mcall-sysv-eabi
           Specify both -mcall-sysv and -meabi options.

       -mcall-sysv-noeabi
           Specify both -mcall-sysv and -mno-eabi options.

       -mcall-aix
           On System V.4 and embedded PowerPC systems compile code using call-
           ing conventions that are similar to those used on AIX.  This is the
           default if you configured GCC using powerpc-*-eabiaix.

       -mcall-solaris
           On System V.4 and embedded PowerPC systems compile code for the
           Solaris operating system.

       -mcall-linux
           On System V.4 and embedded PowerPC systems compile code for the
           Linux-based GNU system.

       -mcall-gnu
           On System V.4 and embedded PowerPC systems compile code for the
           Hurd-based GNU system.

       -mcall-netbsd
           On System V.4 and embedded PowerPC systems compile code for the
           NetBSD operating system.

       -maix-struct-return
           Return all structures in memory (as specified by the AIX ABI).

       -msvr4-struct-return
           Return structures smaller than 8 bytes in registers (as specified
           by the SVR4 ABI).

       -mabi=altivec
           Extend the current ABI with AltiVec ABI extensions.  This does not
           change the default ABI, instead it adds the AltiVec ABI extensions
           to the current ABI.

       -mabi=no-altivec
           Disable AltiVec ABI extensions for the current ABI.

       -mprototype
       -mno-prototype
           On System V.4 and embedded PowerPC systems assume that all calls to
           variable argument functions are properly prototyped.  Otherwise,
           the compiler must insert an instruction before every non prototyped
           call to set or clear bit 6 of the condition code register (CR) to
           indicate whether floating point values were passed in the floating
           point registers in case the function takes a variable arguments.

       -mmvme
           On embedded PowerPC systems, assume that the startup module is
           called crt0.o and the standard C libraries are libmvme.a and
           libc.a.

       -mads
           On embedded PowerPC systems, assume that the startup module is
           called crt0.o and the standard C libraries are libads.a and libc.a.

       -myellowknife
           On embedded PowerPC systems, assume that the startup module is
           called crt0.o and the standard C libraries are libyk.a and libc.a.

       -mvxworks
           On System V.4 and embedded PowerPC systems, specify that you are
           compiling for a VxWorks system.

       -memb
           On embedded PowerPC systems, set the PPC_EMB bit in the ELF flags
           header to indicate that eabi extended relocations are used.

       -meabi
       -mno-eabi
           On System V.4 and embedded PowerPC systems do (do not) adhere to
           the Embedded Applications Binary Interface (eabi) which is a set of
           modifications to the System V.4 specifications.  Selecting -meabi
           means that the stack is aligned to an 8 byte boundary, a function
           "__eabi" is called to from "main" to set up the eabi environment,
           and the -msdata option can use both "r2" and "r13" to point to two
           separate small data areas.  Selecting -mno-eabi means that the
           stack is aligned to a 16 byte boundary, do not call an initializa-
           tion function from "main", and the -msdata option will only use
           "r13" to point to a single small data area.  The -meabi option is
           on by default if you configured GCC using one of the pow-
           erpc*-*-eabi* options.

       -msdata=eabi
           On System V.4 and embedded PowerPC systems, put small initialized
           "const" global and static data in the .sdata2 section, which is
           pointed to by register "r2".  Put small initialized non-"const"
           global and static data in the .sdata section, which is pointed to
           by register "r13".  Put small uninitialized global and static data
           in the .sbss section, which is adjacent to the .sdata section.  The
           -msdata=eabi option is incompatible with the -mrelocatable option.
           The -msdata=eabi option also sets the -memb option.

       -msdata=sysv
           On System V.4 and embedded PowerPC systems, put small global and
           static data in the .sdata section, which is pointed to by register
           "r13".  Put small uninitialized global and static data in the .sbss
           section, which is adjacent to the .sdata section.  The -msdata=sysv
           option is incompatible with the -mrelocatable option.

       -msdata=default
       -msdata
           On System V.4 and embedded PowerPC systems, if -meabi is used, com-
           pile code the same as -msdata=eabi, otherwise compile code the same

       -msdata=none
       -mno-sdata
           On embedded PowerPC systems, put all initialized global and static
           data in the .data section, and all uninitialized data in the .bss
           section.

       -G num
           On embedded PowerPC systems, put global and static items less than
           or equal to num bytes into the small data or bss sections instead
           of the normal data or bss section.  By default, num is 8.  The -G
           num switch is also passed to the linker.  All modules should be
           compiled with the same -G num value.

       -mregnames
       -mno-regnames
           On System V.4 and embedded PowerPC systems do (do not) emit regis-
           ter names in the assembly language output using symbolic forms.

       -pthread
           Adds support for multithreading with the pthreads library.  This
           option sets flags for both the preprocessor and linker.

       IBM RT Options

       These -m options are defined for the IBM RT PC:

       -min-line-mul
           Use an in-line code sequence for integer multiplies.  This is the
           default.

       -mcall-lib-mul
           Call "lmul$$" for integer multiples.

       -mfull-fp-blocks
           Generate full-size floating point data blocks, including the mini-
           mum amount of scratch space recommended by IBM.  This is the
           default.

       -mminimum-fp-blocks
           Do not include extra scratch space in floating point data blocks.
           This results in smaller code, but slower execution, since scratch
           space must be allocated dynamically.

       -mfp-arg-in-fpregs
           Use a calling sequence incompatible with the IBM calling convention
           in which floating point arguments are passed in floating point reg-
           isters.  Note that "varargs.h" and "stdarg.h" will not work with
           floating point operands if this option is specified.

       -mfp-arg-in-gregs
           Use the normal calling convention for floating point arguments.
           This is the default.

       -mhc-struct-return
           Return structures of more than one word in memory, rather than in a
           register.  This provides compatibility with the MetaWare HighC (hc)
           compiler.  Use the option -fpcc-struct-return for compatibility

       These -m options are defined for the MIPS family of computers:

       -march=cpu-type
           Assume the defaults for the machine type cpu-type when generating
           instructions.  The choices for cpu-type are  r2000, r3000, r3900,
           r4000, r4100, r4300, r4400, r4600, r4650, r5000, r6000, r8000, and
           orion.  Additionally, the r2000, r3000, r4000, r5000, and r6000 can
           be abbreviated as r2k (or r2K), r3k, etc.

       -mtune=cpu-type
           Assume the defaults for the machine type cpu-type when scheduling
           instructions.  The choices for cpu-type are r2000, r3000, r3900,
           r4000, r4100, r4300, r4400, r4600, r4650, r5000, r6000, r8000, and
           orion.  Additionally, the r2000, r3000, r4000, r5000, and r6000 can
           be abbreviated as r2k (or r2K), r3k, etc.  While picking a specific
           cpu-type will schedule things appropriately for that particular
           chip, the compiler will not generate any code that does not meet
           level 1 of the MIPS ISA (instruction set architecture) without a
           -mipsX or -mabi switch being used.

       -mcpu=cpu-type
           This is identical to specifying both -march and -mtune.

       -mips1
           Issue instructions from level 1 of the MIPS ISA.  This is the
           default.  r3000 is the default cpu-type at this ISA level.

       -mips2
           Issue instructions from level 2 of the MIPS ISA (branch likely,
           square root instructions).  r6000 is the default cpu-type at this
           ISA level.

       -mips3
           Issue instructions from level 3 of the MIPS ISA (64-bit instruc-
           tions).  r4000 is the default cpu-type at this ISA level.

       -mips4
           Issue instructions from level 4 of the MIPS ISA (conditional move,
           prefetch, enhanced FPU instructions).  r8000 is the default cpu-
           type at this ISA level.

       -mfp32
           Assume that 32 32-bit floating point registers are available.  This
           is the default.

       -mfp64
           Assume that 32 64-bit floating point registers are available.  This
           is the default when the -mips3 option is used.

       -mfused-madd
       -mno-fused-madd
           Generate code that uses (does not use) the floating point multiply
           and accumulate instructions, when they are available.  These
           instructions are generated by default if they are available, but
           this may be undesirable if the extra precision causes problems or
           on certain chips in the mode where denormals are rounded to zero
           This is the default when the -mips3 option is used.

       -mint64
           Force int and long types to be 64 bits wide.  See -mlong32 for an
           explanation of the default, and the width of pointers.

       -mlong64
           Force long types to be 64 bits wide.  See -mlong32 for an explana-
           tion of the default, and the width of pointers.

       -mlong32
           Force long, int, and pointer types to be 32 bits wide.

           If none of -mlong32, -mlong64, or -mint64 are set, the size of
           ints, longs, and pointers depends on the ABI and ISA chosen.  For
           -mabi=32, and -mabi=n32, ints and longs are 32 bits wide.  For
           -mabi=64, ints are 32 bits, and longs are 64 bits wide.  For
           -mabi=eabi and either -mips1 or -mips2, ints and longs are 32 bits
           wide.  For -mabi=eabi and higher ISAs, ints are 32 bits, and longs
           are 64 bits wide.  The width of pointer types is the smaller of the
           width of longs or the width of general purpose registers (which in
           turn depends on the ISA).

       -mabi=32
       -mabi=o64
       -mabi=n32
       -mabi=64
       -mabi=eabi
           Generate code for the indicated ABI.  The default instruction level
           is -mips1 for 32, -mips3 for n32, and -mips4 otherwise.  Con-
           versely, with -mips1 or -mips2, the default ABI is 32; otherwise,
           the default ABI is 64.

       -mmips-as
           Generate code for the MIPS assembler, and invoke mips-tfile to add
           normal debug information.  This is the default for all platforms
           except for the OSF/1 reference platform, using the OSF/rose object
           format.  If the either of the -gstabs or -gstabs+ switches are
           used, the mips-tfile program will encapsulate the stabs within MIPS
           ECOFF.

       -mgas
           Generate code for the GNU assembler.  This is the default on the
           OSF/1 reference platform, using the OSF/rose object format.  Also,
           this is the default if the configure option --with-gnu-as is used.

       -msplit-addresses
       -mno-split-addresses
           Generate code to load the high and low parts of address constants
           separately.  This allows GCC to optimize away redundant loads of
           the high order bits of addresses.  This optimization requires GNU
           as and GNU ld.  This optimization is enabled by default for some
           embedded targets where GNU as and GNU ld are standard.

       -mrnames
       -mno-rnames
           The -mrnames switch says to output code using the MIPS software
           two words for short global or static data items.  This is on by
           default if optimization is selected.

       -mstats
       -mno-stats
           For each non-inline function processed, the -mstats switch causes
           the compiler to emit one line to the standard error file to print
           statistics about the program (number of registers saved, stack
           size, etc.).

       -mmemcpy
       -mno-memcpy
           The -mmemcpy switch makes all block moves call the appropriate
           string function (memcpy or bcopy) instead of possibly generating
           inline code.

       -mmips-tfile
       -mno-mips-tfile
           The -mno-mips-tfile switch causes the compiler not postprocess the
           object file with the mips-tfile program, after the MIPS assembler
           has generated it to add debug support.  If mips-tfile is not run,
           then no local variables will be available to the debugger.  In
           addition, stage2 and stage3 objects will have the temporary file
           names passed to the assembler embedded in the object file, which
           means the objects will not compare the same.  The -mno-mips-tfile
           switch should only be used when there are bugs in the mips-tfile
           program that prevents compilation.

       -msoft-float
           Generate output containing library calls for floating point.  Warn-
           ing: the requisite libraries are not part of GCC.  Normally the
           facilities of the machine's usual C compiler are used, but this
           can't be done directly in cross-compilation.  You must make your
           own arrangements to provide suitable library functions for
           cross-compilation.

       -mhard-float
           Generate output containing floating point instructions.  This is
           the default if you use the unmodified sources.

       -mabicalls
       -mno-abicalls
           Emit (or do not emit) the pseudo operations .abicalls, .cpload, and
           .cprestore that some System V.4 ports use for position independent
           code.

       -mlong-calls
       -mno-long-calls
           Do all calls with the JALR instruction, which requires loading up a
           function's address into a register before the call.  You need to
           use this switch, if you call outside of the current 512 megabyte
           segment to functions that are not through pointers.

       -mhalf-pic
       -mno-half-pic
           Put pointers to extern references into the data section and load
           them up, rather than put the references in the text section.

       -membedded-data
       -mno-embedded-data
           Allocate variables to the read-only data section first if possible,
           then next in the small data section if possible, otherwise in data.
           This gives slightly slower code than the default, but reduces the
           amount of RAM required when executing, and thus may be preferred
           for some embedded systems.

       -muninit-const-in-rodata
       -mno-uninit-const-in-rodata
           When used together with -membedded-data, it will always store
           uninitialized const variables in the read-only data section.

       -msingle-float
       -mdouble-float
           The -msingle-float switch tells gcc to assume that the floating
           point coprocessor only supports single precision operations, as on
           the r4650 chip.  The -mdouble-float switch permits gcc to use dou-
           ble precision operations.  This is the default.

       -mmad
       -mno-mad
           Permit use of the mad, madu and mul instructions, as on the r4650
           chip.

       -m4650
           Turns on -msingle-float, -mmad, and, at least for now, -mcpu=r4650.

       -mips16
       -mno-mips16
           Enable 16-bit instructions.

       -mentry
           Use the entry and exit pseudo ops.  This option can only be used
           with -mips16.

       -EL Compile code for the processor in little endian mode.  The requi-
           site libraries are assumed to exist.

       -EB Compile code for the processor in big endian mode.  The requisite
           libraries are assumed to exist.

       -G num
           Put global and static items less than or equal to num bytes into
           the small data or bss sections instead of the normal data or bss
           section.  This allows the assembler to emit one word memory refer-
           ence instructions based on the global pointer (gp or $28), instead
           of the normal two words used.  By default, num is 8 when the MIPS
           assembler is used, and 0 when the GNU assembler is used.  The -G
           num switch is also passed to the assembler and linker.  All modules
           should be compiled with the same -G num value.

       -nocpp
           Tell the MIPS assembler to not run its preprocessor over user
           assembler files (with a .s suffix) when assembling them.

       -mno-flush-func
           Specifies the function to call to flush the I and D caches, or to
           not call any such function.  If called, the function must take the
           same arguments as the common "_flush_func()", that is, the address
           of the memory range for which the cache is being flushed, the size
           of the memory range, and the number 3 (to flush both caches).  The
           default depends on the target gcc was configured for, but commonly
           is either _flush_func or __cpu_flush.

       These options are defined by the macro "TARGET_SWITCHES" in the machine
       description.  The default for the options is also defined by that
       macro, which enables you to change the defaults.

       Intel 386 and AMD x86-64 Options

       These -m options are defined for the i386 and x86-64 family of comput-
       ers:

       -mcpu=cpu-type
           Tune to cpu-type everything applicable about the generated code,
           except for the ABI and the set of available instructions.  The
           choices for cpu-type are i386, i486, i586, i686, pentium, pentium-
           mmx, pentiumpro, pentium2, pentium3, pentium4, k6, k6-2, k6-3,
           athlon, athlon-tbird, athlon-4, athlon-xp and athlon-mp.

           While picking a specific cpu-type will schedule things appropri-
           ately for that particular chip, the compiler will not generate any
           code that does not run on the i386 without the -march=cpu-type
           option being used.  i586 is equivalent to pentium and i686 is
           equivalent to pentiumpro.  k6 and athlon are the AMD chips as
           opposed to the Intel ones.

       -march=cpu-type
           Generate instructions for the machine type cpu-type.  The choices
           for cpu-type are the same as for -mcpu.  Moreover, specifying
           -march=cpu-type implies -mcpu=cpu-type.

       -m386
       -m486
       -mpentium
       -mpentiumpro
           These options are synonyms for -mcpu=i386, -mcpu=i486, -mcpu=pen-
           tium, and -mcpu=pentiumpro respectively.  These synonyms are depre-
           cated.

       -mfpmath=unit
           generate floating point arithmetics for selected unit unit.  the
           choices for unit are:

           387 Use the standard 387 floating point coprocessor present major-
               ity of chips and emulated otherwise.  Code compiled with this
               option will run almost everywhere.  The temporary results are
               computed in 80bit precesion instead of precision specified by
               the type resulting in slightly different results compared to
               most of other chips. See -ffloat-store for more detailed
               description.

               chips supports double precision arithmetics too.

               For i387 you need to use -march=cpu-type, -msse or -msse2
               switches to enable SSE extensions and make this option effec-
               tive.  For x86-64 compiler, these extensions are enabled by
               default.

               The resulting code should be considerably faster in majority of
               cases and avoid the numerical instability problems of 387 code,
               but may break some existing code that expects temporaries to be
               80bit.

               This is the default choice for x86-64 compiler.

           sse,387
               Attempt to utilize both instruction sets at once.  This effec-
               tivly double the amount of available registers and on chips
               with separate execution units for 387 and SSE the execution
               resources too.  Use this option with care, as it is still
               experimental, because gcc register allocator does not model
               separate functional units well resulting in instable perfor-
               mance.

       -masm=dialect
           Output asm instructions using selected dialect. Supported choices
           are intel or att (the default one).

       -mieee-fp
       -mno-ieee-fp
           Control whether or not the compiler uses IEEE floating point com-
           parisons.  These handle correctly the case where the result of a
           comparison is unordered.

       -msoft-float
           Generate output containing library calls for floating point.  Warn-
           ing: the requisite libraries are not part of GCC.  Normally the
           facilities of the machine's usual C compiler are used, but this
           can't be done directly in cross-compilation.  You must make your
           own arrangements to provide suitable library functions for
           cross-compilation.

           On machines where a function returns floating point results in the
           80387 register stack, some floating point opcodes may be emitted
           even if -msoft-float is used.

       -mno-fp-ret-in-387
           Do not use the FPU registers for return values of functions.

           The usual calling convention has functions return values of types
           "float" and "double" in an FPU register, even if there is no FPU.
           The idea is that the operating system should emulate an FPU.

           The option -mno-fp-ret-in-387 causes such values to be returned in
           ordinary CPU registers instead.

       -mno-fancy-math-387
           Some 387 emulators do not support the "sin", "cos" and "sqrt"

       -mno-align-double
           Control whether GCC aligns "double", "long double", and "long long"
           variables on a two word boundary or a one word boundary.  Aligning
           "double" variables on a two word boundary will produce code that
           runs somewhat faster on a Pentium at the expense of more memory.

           Warning: if you use the -malign-double switch, structures contain-
           ing the above types will be aligned differently than the published
           application binary interface specifications for the 386 and will
           not be binary compatible with structures in code compiled without
           that switch.

       -m128bit-long-double
           Control the size of "long double" type. i386 application binary
           interface specify the size to be 12 bytes, while modern architec-
           tures (Pentium and newer) prefer "long double" aligned to 8 or 16
           byte boundary.  This is impossible to reach with 12 byte long dou-
           bles in the array accesses.

           Warning: if you use the -m128bit-long-double switch, the structures
           and arrays containing "long double" will change their size as well
           as function calling convention for function taking "long double"
           will be modified.

       -m96bit-long-double
           Set the size of "long double" to 96 bits as required by the i386
           application binary interface.  This is the default.

       -msvr3-shlib
       -mno-svr3-shlib
           Control whether GCC places uninitialized local variables into the
           "bss" or "data" segments.  -msvr3-shlib places them into "bss".
           These options are meaningful only on System V Release 3.

       -mrtd
           Use a different function-calling convention, in which functions
           that take a fixed number of arguments return with the "ret" num
           instruction, which pops their arguments while returning.  This
           saves one instruction in the caller since there is no need to pop
           the arguments there.

           You can specify that an individual function is called with this
           calling sequence with the function attribute stdcall.  You can also
           override the -mrtd option by using the function attribute cdecl.

           Warning: this calling convention is incompatible with the one nor-
           mally used on Unix, so you cannot use it if you need to call
           libraries compiled with the Unix compiler.

           Also, you must provide function prototypes for all functions that
           take variable numbers of arguments (including "printf"); otherwise
           incorrect code will be generated for calls to those functions.

           In addition, seriously incorrect code will result if you call a
           function with too many arguments.  (Normally, extra arguments are
           harmlessly ignored.)


       -mpreferred-stack-boundary=num
           Attempt to keep the stack boundary aligned to a 2 raised to num
           byte boundary.  If -mpreferred-stack-boundary is not specified, the
           default is 4 (16 bytes or 128 bits), except when optimizing for
           code size (-Os), in which case the default is the minimum correct
           alignment (4 bytes for x86, and 8 bytes for x86-64).

           On Pentium and PentiumPro, "double" and "long double" values should
           be aligned to an 8 byte boundary (see -malign-double) or suffer
           significant run time performance penalties.  On Pentium III, the
           Streaming SIMD Extension (SSE) data type "__m128" suffers similar
           penalties if it is not 16 byte aligned.

           To ensure proper alignment of this values on the stack, the stack
           boundary must be as aligned as that required by any value stored on
           the stack.  Further, every function must be generated such that it
           keeps the stack aligned.  Thus calling a function compiled with a
           higher preferred stack boundary from a function compiled with a
           lower preferred stack boundary will most likely misalign the stack.
           It is recommended that libraries that use callbacks always use the
           default setting.

           This extra alignment does consume extra stack space, and generally
           increases code size.  Code that is sensitive to stack space usage,
           such as embedded systems and operating system kernels, may want to
           reduce the preferred alignment to -mpreferred-stack-boundary=2.

       -mmmx
       -mno-mmx
       -msse
       -mno-sse
       -msse2
       -mno-sse2
       -m3dnow
       -mno-3dnow
           These switches enable or disable the use of built-in functions that
           allow direct access to the MMX, SSE and 3Dnow extensions of the
           instruction set.

           To have SSE/SSE2 instructions generated automatically from float-
           ing-point code, see -mfpmath=sse.

       -mpush-args
       -mno-push-args
           Use PUSH operations to store outgoing parameters.  This method is
           shorter and usually equally fast as method using SUB/MOV operations
           and is enabled by default.  In some cases disabling it may improve
           performance because of improved scheduling and reduced dependen-
           cies.

       -maccumulate-outgoing-args
           If enabled, the maximum amount of space required for outgoing argu-
           ments will be computed in the function prologue.  This is faster on
           most modern CPUs because of reduced dependencies, improved schedul-
           ing and reduced stack usage when preferred stack boundary is not
           equal to 2.  The drawback is a notable increase in code size.  This

       -mno-align-stringops
           Do not align destination of inlined string operations.  This switch
           reduces code size and improves performance in case the destination
           is already aligned, but gcc don't know about it.

       -minline-all-stringops
           By default GCC inlines string operations only when destination is
           known to be aligned at least to 4 byte boundary.  This enables more
           inlining, increase code size, but may improve performance of code
           that depends on fast memcpy, strlen and memset for short lengths.

       -momit-leaf-frame-pointer
           Don't keep the frame pointer in a register for leaf functions.
           This avoids the instructions to save, set up and restore frame
           pointers and makes an extra register available in leaf functions.
           The option -fomit-frame-pointer removes the frame pointer for all
           functions which might make debugging harder.

       These -m switches are supported in addition to the above on AMD x86-64
       processors in 64-bit environments.

       -m32
       -m64
           Generate code for a 32-bit or 64-bit environment.  The 32-bit envi-
           ronment sets int, long and pointer to 32 bits and generates code
           that runs on any i386 system.  The 64-bit environment sets int to
           32 bits and long and pointer to 64 bits and generates code for
           AMD's x86-64 architecture.

       -mno-red-zone
           Do not use a so called red zone for x86-64 code.  The red zone is
           mandated by the x86-64 ABI, it is a 128-byte area beyond the loca-
           tion of the stack pointer that will not be modified by signal or
           interrupt handlers and therefore can be used for temporary data
           without adjusting the stack pointer.  The flag -mno-red-zone dis-
           ables this red zone.

       -mcmodel=small
           Generate code for the small code model: the program and its symbols
           must be linked in the lower 2 GB of the address space.  Pointers
           are 64 bits.  Programs can be statically or dynamically linked.
           This is the default code model.

       -mcmodel=kernel
           Generate code for the kernel code model.  The kernel runs in the
           negative 2 GB of the address space.  This model has to be used for
           Linux kernel code.

       -mcmodel=medium
           Generate code for the medium model: The program is linked in the
           lower 2 GB of the address space but symbols can be located anywhere
           in the address space.  Programs can be statically or dynamically
           linked, but building of shared libraries are not supported with the
           medium model.

       -mcmodel=large
           Generate code for the large model: This model makes no assumptions
           architecture-type are 1.0 for PA 1.0, 1.1 for PA 1.1, and 2.0 for
           PA 2.0 processors.  Refer to /usr/lib/sched.models on an HP-UX sys-
           tem to determine the proper architecture option for your machine.
           Code compiled for lower numbered architectures will run on higher
           numbered architectures, but not the other way around.

           PA 2.0 support currently requires gas snapshot 19990413 or later.
           The next release of binutils (current is 2.9.1) will probably con-
           tain PA 2.0 support.

       -mpa-risc-1-0
       -mpa-risc-1-1
       -mpa-risc-2-0
           Synonyms for -march=1.0, -march=1.1, and -march=2.0 respectively.

       -mbig-switch
           Generate code suitable for big switch tables.  Use this option only
           if the assembler/linker complain about out of range branches within
           a switch table.

       -mjump-in-delay
           Fill delay slots of function calls with unconditional jump instruc-
           tions by modifying the return pointer for the function call to be
           the target of the conditional jump.

       -mdisable-fpregs
           Prevent floating point registers from being used in any manner.
           This is necessary for compiling kernels which perform lazy context
           switching of floating point registers.  If you use this option and
           attempt to perform floating point operations, the compiler will
           abort.

       -mdisable-indexing
           Prevent the compiler from using indexing address modes.  This
           avoids some rather obscure problems when compiling MIG generated
           code under MACH.

       -mno-space-regs
           Generate code that assumes the target has no space registers.  This
           allows GCC to generate faster indirect calls and use unscaled index
           address modes.

           Such code is suitable for level 0 PA systems and kernels.

       -mfast-indirect-calls
           Generate code that assumes calls never cross space boundaries.
           This allows GCC to emit code which performs faster indirect calls.

           This option will not work in the presence of shared libraries or
           nested functions.

       -mlong-load-store
           Generate 3-instruction load and store sequences as sometimes
           required by the HP-UX 10 linker.  This is equivalent to the +k
           option to the HP compilers.

       -mportable-runtime
           8000.  Refer to /usr/lib/sched.models on an HP-UX system to deter-
           mine the proper scheduling option for your machine.

       -mlinker-opt
           Enable the optimization pass in the HPUX linker.  Note this makes
           symbolic debugging impossible.  It also triggers a bug in the HPUX
           8 and HPUX 9 linkers in which they give bogus error messages when
           linking some programs.

       -msoft-float
           Generate output containing library calls for floating point.  Warn-
           ing: the requisite libraries are not available for all HPPA tar-
           gets.  Normally the facilities of the machine's usual C compiler
           are used, but this cannot be done directly in cross-compilation.
           You must make your own arrangements to provide suitable library
           functions for cross-compilation.  The embedded target hppa1.1-*-pro
           does provide software floating point support.

           -msoft-float changes the calling convention in the output file;
           therefore, it is only useful if you compile all of a program with
           this option.  In particular, you need to compile libgcc.a, the
           library that comes with GCC, with -msoft-float in order for this to
           work.

       Intel 960 Options

       These -m options are defined for the Intel 960 implementations:

       -mcpu-type
           Assume the defaults for the machine type cpu-type for some of the
           other options, including instruction scheduling, floating point
           support, and addressing modes.  The choices for cpu-type are ka,
           kb, mc, ca, cf, sa, and sb.  The default is kb.

       -mnumerics
       -msoft-float
           The -mnumerics option indicates that the processor does support
           floating-point instructions.  The -msoft-float option indicates
           that floating-point support should not be assumed.

       -mleaf-procedures
       -mno-leaf-procedures
           Do (or do not) attempt to alter leaf procedures to be callable with
           the "bal" instruction as well as "call".  This will result in more
           efficient code for explicit calls when the "bal" instruction can be
           substituted by the assembler or linker, but less efficient code in
           other cases, such as calls via function pointers, or using a linker
           that doesn't support this optimization.

       -mtail-call
       -mno-tail-call
           Do (or do not) make additional attempts (beyond those of the
           machine-independent portions of the compiler) to optimize tail-
           recursive calls into branches.  You may not want to do this because
           the detection of cases where this is not valid is not totally com-
           plete.  The default is -mno-tail-call.

       -mno-code-align
           Align code to 8-byte boundaries for faster fetching (or don't
           bother).  Currently turned on by default for C-series implementa-
           tions only.

       -mic-compat
       -mic2.0-compat
       -mic3.0-compat
           Enable compatibility with iC960 v2.0 or v3.0.

       -masm-compat
       -mintel-asm
           Enable compatibility with the iC960 assembler.

       -mstrict-align
       -mno-strict-align
           Do not permit (do permit) unaligned accesses.

       -mold-align
           Enable structure-alignment compatibility with Intel's gcc release
           version 1.3 (based on gcc 1.37).  This option implies
           -mstrict-align.

       -mlong-double-64
           Implement type long double as 64-bit floating point numbers.  With-
           out the option long double is implemented by 80-bit floating point
           numbers.  The only reason we have it because there is no 128-bit
           long double support in fp-bit.c yet.  So it is only useful for peo-
           ple using soft-float targets.  Otherwise, we should recommend
           against use of it.

       DEC Alpha Options

       These -m options are defined for the DEC Alpha implementations:

       -mno-soft-float
       -msoft-float
           Use (do not use) the hardware floating-point instructions for
           floating-point operations.  When -msoft-float is specified, func-
           tions in libgcc.a will be used to perform floating-point opera-
           tions.  Unless they are replaced by routines that emulate the
           floating-point operations, or compiled in such a way as to call
           such emulations routines, these routines will issue floating-point
           operations.   If you are compiling for an Alpha without floating-
           point operations, you must ensure that the library is built so as
           not to call them.

           Note that Alpha implementations without floating-point operations
           are required to have floating-point registers.

       -mfp-reg
       -mno-fp-regs
           Generate code that uses (does not use) the floating-point register
           set.  -mno-fp-regs implies -msoft-float.  If the floating-point
           register set is not used, floating point operands are passed in
           integer registers as if they were integers and floating-point
           results are passed in $0 instead of $f0.  This is a non-standard
           The Alpha architecture implements floating-point hardware optimized
           for maximum performance.  It is mostly compliant with the IEEE
           floating point standard.  However, for full compliance, software
           assistance is required.  This option generates code fully IEEE com-
           pliant code except that the inexact-flag is not maintained (see
           below).  If this option is turned on, the preprocessor macro
           "_IEEE_FP" is defined during compilation.  The resulting code is
           less efficient but is able to correctly support denormalized num-
           bers and exceptional IEEE values such as not-a-number and
           plus/minus infinity.  Other Alpha compilers call this option
           -ieee_with_no_inexact.

       -mieee-with-inexact
           This is like -mieee except the generated code also maintains the
           IEEE inexact-flag.  Turning on this option causes the generated
           code to implement fully-compliant IEEE math.  In addition to
           "_IEEE_FP", "_IEEE_FP_EXACT" is defined as a preprocessor macro.
           On some Alpha implementations the resulting code may execute sig-
           nificantly slower than the code generated by default.  Since there
           is very little code that depends on the inexact-flag, you should
           normally not specify this option.  Other Alpha compilers call this
           option -ieee_with_inexact.

       -mfp-trap-mode=trap-mode
           This option controls what floating-point related traps are enabled.
           Other Alpha compilers call this option -fptm trap-mode.  The trap
           mode can be set to one of four values:

           n   This is the default (normal) setting.  The only traps that are
               enabled are the ones that cannot be disabled in software (e.g.,
               division by zero trap).

           u   In addition to the traps enabled by n, underflow traps are
               enabled as well.

           su  Like su, but the instructions are marked to be safe for soft-
               ware completion (see Alpha architecture manual for details).

           sui Like su, but inexact traps are enabled as well.

       -mfp-rounding-mode=rounding-mode
           Selects the IEEE rounding mode.  Other Alpha compilers call this
           option -fprm rounding-mode.  The rounding-mode can be one of:

           n   Normal IEEE rounding mode.  Floating point numbers are rounded
               towards the nearest machine number or towards the even machine
               number in case of a tie.

           m   Round towards minus infinity.

           c   Chopped rounding mode.  Floating point numbers are rounded
               towards zero.

           d   Dynamic rounding mode.  A field in the floating point control
               register (fpcr, see Alpha architecture reference manual) con-
               trols the rounding mode in effect.  The C library initializes
               this register for rounding towards plus infinity.  Thus, unless

           floating point trap.  Depending on the requirements of an applica-
           tion, different levels of precisions can be selected:

           p   Program precision.  This option is the default and means a trap
               handler can only identify which program caused a floating point
               exception.

           f   Function precision.  The trap handler can determine the func-
               tion that caused a floating point exception.

           i   Instruction precision.  The trap handler can determine the
               exact instruction that caused a floating point exception.

           Other Alpha compilers provide the equivalent options called
           -scope_safe and -resumption_safe.

       -mieee-conformant
           This option marks the generated code as IEEE conformant.  You must
           not use this option unless you also specify -mtrap-precision=i and
           either -mfp-trap-mode=su or -mfp-trap-mode=sui.  Its only effect is
           to emit the line .eflag 48 in the function prologue of the gener-
           ated assembly file.  Under DEC Unix, this has the effect that IEEE-
           conformant math library routines will be linked in.

       -mbuild-constants
           Normally GCC examines a 32- or 64-bit integer constant to see if it
           can construct it from smaller constants in two or three instruc-
           tions.  If it cannot, it will output the constant as a literal and
           generate code to load it from the data segment at runtime.

           Use this option to require GCC to construct all integer constants
           using code, even if it takes more instructions (the maximum is
           six).

           You would typically use this option to build a shared library
           dynamic loader.  Itself a shared library, it must relocate itself
           in memory before it can find the variables and constants in its own
           data segment.

       -malpha-as
       -mgas
           Select whether to generate code to be assembled by the vendor-sup-
           plied assembler (-malpha-as) or by the GNU assembler -mgas.

       -mbwx
       -mno-bwx
       -mcix
       -mno-cix
       -mfix
       -mno-fix
       -mmax
       -mno-max
           Indicate whether GCC should generate code to use the optional BWX,
           CIX, FIX and MAX instruction sets.  The default is to use the
           instruction sets supported by the CPU type specified via -mcpu=
           option or that of the CPU on which GCC was built if none was speci-
           fied.
           tions except via assembler macros.  Use of these macros does not
           allow optimial instruction scheduling.  GNU binutils as of version
           2.12 supports a new syntax that allows the compiler to explicitly
           mark which relocations should apply to which instructions.  This
           option is mostly useful for debugging, as GCC detects the capabili-
           ties of the assembler when it is built and sets the default accord-
           ingly.

       -msmall-data
       -mlarge-data
           When -mexplicit-relocs is in effect, static data is accessed via
           gp-relative relocations.  When -msmall-data is used, objects 8
           bytes long or smaller are placed in a small data area (the ".sdata"
           and ".sbss" sections) and are accessed via 16-bit relocations off
           of the $gp register.  This limits the size of the small data area
           to 64KB, but allows the variables to be directly accessed via a
           single instruction.

           The default is -mlarge-data.  With this option the data area is
           limited to just below 2GB.  Programs that require more than 2GB of
           data must use "malloc" or "mmap" to allocate the data in the heap
           instead of in the program's data segment.

           When generating code for shared libraries, -fpic implies
           -msmall-data and -fPIC implies -mlarge-data.

       -mcpu=cpu_type
           Set the instruction set and instruction scheduling parameters for
           machine type cpu_type.  You can specify either the EV style name or
           the corresponding chip number.  GCC supports scheduling parameters
           for the EV4, EV5 and EV6 family of processors and will choose the
           default values for the instruction set from the processor you spec-
           ify.  If you do not specify a processor type, GCC will default to
           the processor on which the compiler was built.

           Supported values for cpu_type are

           ev4
           ev45
           21064
               Schedules as an EV4 and has no instruction set extensions.

           ev5
           21164
               Schedules as an EV5 and has no instruction set extensions.

           ev56
           21164a
               Schedules as an EV5 and supports the BWX extension.

           pca56
           21164pc
           21164PC
               Schedules as an EV5 and supports the BWX and MAX extensions.

           ev6
           21264
           Set only the instruction scheduling parameters for machine type
           cpu_type.  The instruction set is not changed.

       -mmemory-latency=time
           Sets the latency the scheduler should assume for typical memory
           references as seen by the application.  This number is highly
           dependent on the memory access patterns used by the application and
           the size of the external cache on the machine.

           Valid options for time are

           number
               A decimal number representing clock cycles.

           L1
           L2
           L3
           main
               The compiler contains estimates of the number of clock cycles
               for ``typical'' EV4 & EV5 hardware for the Level 1, 2 & 3
               caches (also called Dcache, Scache, and Bcache), as well as to
               main memory.  Note that L3 is only valid for EV5.

       DEC Alpha/VMS Options

       These -m options are defined for the DEC Alpha/VMS implementations:

       -mvms-return-codes
           Return VMS condition codes from main.  The default is to return
           POSIX style condition (e.g. error) codes.

       Clipper Options

       These -m options are defined for the Clipper implementations:

       -mc300
           Produce code for a C300 Clipper processor.  This is the default.

       -mc400
           Produce code for a C400 Clipper processor, i.e. use floating point
           registers f8--f15.

       H8/300 Options

       These -m options are defined for the H8/300 implementations:

       -mrelax
           Shorten some address references at link time, when possible; uses
           the linker option -relax.

       -mh Generate code for the H8/300H.

       -ms Generate code for the H8/S.

       -ms2600
           Generate code for the H8/S2600.  This switch must be used with -ms.

       SH Options

       These -m options are defined for the SH implementations:

       -m1 Generate code for the SH1.

       -m2 Generate code for the SH2.

       -m3 Generate code for the SH3.

       -m3e
           Generate code for the SH3e.

       -m4-nofpu
           Generate code for the SH4 without a floating-point unit.

       -m4-single-only
           Generate code for the SH4 with a floating-point unit that only sup-
           ports single-precision arithmetic.

       -m4-single
           Generate code for the SH4 assuming the floating-point unit is in
           single-precision mode by default.

       -m4 Generate code for the SH4.

       -mb Compile code for the processor in big endian mode.

       -ml Compile code for the processor in little endian mode.

       -mdalign
           Align doubles at 64-bit boundaries.  Note that this changes the
           calling conventions, and thus some functions from the standard C
           library will not work unless you recompile it first with -mdalign.

       -mrelax
           Shorten some address references at link time, when possible; uses
           the linker option -relax.

       -mbigtable
           Use 32-bit offsets in "switch" tables.  The default is to use
           16-bit offsets.

       -mfmovd
           Enable the use of the instruction "fmovd".

       -mhitachi
           Comply with the calling conventions defined by Hitachi.

       -mnomacsave
           Mark the "MAC" register as call-clobbered, even if -mhitachi is
           given.

       -mieee
           Increase IEEE-compliance of floating-point code.

       -misize
       -mprefergot
           When generating position-independent code, emit function calls
           using the Global Offset Table instead of the Procedure Linkage Ta-
           ble.

       -musermode
           Generate a library function call to invalidate instruction cache
           entries, after fixing up a trampoline.  This library function call
           doesn't assume it can write to the whole memory address space.
           This is the default when the target is "sh-*-linux*".

       Options for System V

       These additional options are available on System V Release 4 for com-
       patibility with other compilers on those systems:

       -G  Create a shared object.  It is recommended that -symbolic or
           -shared be used instead.

       -Qy Identify the versions of each tool used by the compiler, in a
           ".ident" assembler directive in the output.

       -Qn Refrain from adding ".ident" directives to the output file (this is
           the default).

       -YP,dirs
           Search the directories dirs, and no others, for libraries specified
           with -l.

       -Ym,dir
           Look in the directory dir to find the M4 preprocessor.  The assem-
           bler uses this option.

       TMS320C3x/C4x Options

       These -m options are defined for TMS320C3x/C4x implementations:

       -mcpu=cpu_type
           Set the instruction set, register set, and instruction scheduling
           parameters for machine type cpu_type.  Supported values for
           cpu_type are c30, c31, c32, c40, and c44.  The default is c40 to
           generate code for the TMS320C40.

       -mbig-memory
       -mbig
       -msmall-memory
       -msmall
           Generates code for the big or small memory model.  The small memory
           model assumed that all data fits into one 64K word page.  At run-
           time the data page (DP) register must be set to point to the 64K
           page containing the .bss and .data program sections.  The big mem-
           ory model is the default and requires reloading of the DP register
           for every direct memory access.

       -mbk
       -mno-bk
           Allow (disallow) allocation of general integer operands into the
           to reverse a loop so that it can utilise the decrement and branch
           instruction, but will give up if there is more than one memory ref-
           erence in the loop.  Thus a loop where the loop counter is decre-
           mented can generate slightly more efficient code, in cases where
           the RPTB instruction cannot be utilised.

       -mdp-isr-reload
       -mparanoid
           Force the DP register to be saved on entry to an interrupt service
           routine (ISR), reloaded to point to the data section, and restored
           on exit from the ISR.  This should not be required unless someone
           has violated the small memory model by modifying the DP register,
           say within an object library.

       -mmpyi
       -mno-mpyi
           For the C3x use the 24-bit MPYI instruction for integer multiplies
           instead of a library call to guarantee 32-bit results.  Note that
           if one of the operands is a constant, then the multiplication will
           be performed using shifts and adds.  If the -mmpyi option is not
           specified for the C3x, then squaring operations are performed
           inline instead of a library call.

       -mfast-fix
       -mno-fast-fix
           The C3x/C4x FIX instruction to convert a floating point value to an
           integer value chooses the nearest integer less than or equal to the
           floating point value rather than to the nearest integer.  Thus if
           the floating point number is negative, the result will be incor-
           rectly truncated an additional code is necessary to detect and cor-
           rect this case.  This option can be used to disable generation of
           the additional code required to correct the result.

       -mrptb
       -mno-rptb
           Enable (disable) generation of repeat block sequences using the
           RPTB instruction for zero overhead looping.  The RPTB construct is
           only used for innermost loops that do not call functions or jump
           across the loop boundaries.  There is no advantage having nested
           RPTB loops due to the overhead required to save and restore the RC,
           RS, and RE registers.  This is enabled by default with -O2.

       -mrpts=count
       -mno-rpts
           Enable (disable) the use of the single instruction repeat instruc-
           tion RPTS.  If a repeat block contains a single instruction, and
           the loop count can be guaranteed to be less than the value count,
           GCC will emit a RPTS instruction instead of a RPTB.  If no value is
           specified, then a RPTS will be emitted even if the loop count can-
           not be determined at compile time.  Note that the repeated instruc-
           tion following RPTS does not have to be reloaded from memory each
           iteration, thus freeing up the CPU buses for operands.  However,
           since interrupts are blocked by this instruction, it is disabled by
           default.

       -mloop-unsigned
       -mno-loop-unsigned
           happy with.  This also enforces compatibility with the API employed
           by the TI C3x C compiler.  For example, long doubles are passed as
           structures rather than in floating point registers.

       -mregparm
       -mmemparm
           Generate code that uses registers (stack) for passing arguments to
           functions.  By default, arguments are passed in registers where
           possible rather than by pushing arguments on to the stack.

       -mparallel-insns
       -mno-parallel-insns
           Allow the generation of parallel instructions.  This is enabled by
           default with -O2.

       -mparallel-mpy
       -mno-parallel-mpy
           Allow the generation of MPY||ADD and MPY||SUB parallel instruc-
           tions, provided -mparallel-insns is also specified.  These instruc-
           tions have tight register constraints which can pessimize the code
           generation of large functions.

       V850 Options

       These -m options are defined for V850 implementations:

       -mlong-calls
       -mno-long-calls
           Treat all calls as being far away (near).  If calls are assumed to
           be far away, the compiler will always load the functions address up
           into a register, and call indirect through the pointer.

       -mno-ep
       -mep
           Do not optimize (do optimize) basic blocks that use the same index
           pointer 4 or more times to copy pointer into the "ep" register, and
           use the shorter "sld" and "sst" instructions.  The -mep option is
           on by default if you optimize.

       -mno-prolog-function
       -mprolog-function
           Do not use (do use) external functions to save and restore regis-
           ters at the prolog and epilog of a function.  The external func-
           tions are slower, but use less code space if more than one function
           saves the same number of registers.  The -mprolog-function option
           is on by default if you optimize.

       -mspace
           Try to make the code as small as possible.  At present, this just
           turns on the -mep and -mprolog-function options.

       -mtda=n
           Put static or global variables whose size is n bytes or less into
           the tiny data area that register "ep" points to.  The tiny data
           area can hold up to 256 bytes in total (128 bytes for byte refer-
           ences).

       -mv850
           Specify that the target processor is the V850.

       -mbig-switch
           Generate code suitable for big switch tables.  Use this option only
           if the assembler/linker complain about out of range branches within
           a switch table.

       ARC Options

       These options are defined for ARC implementations:

       -EL Compile code for little endian mode.  This is the default.

       -EB Compile code for big endian mode.

       -mmangle-cpu
           Prepend the name of the cpu to all public symbol names.  In multi-
           ple-processor systems, there are many ARC variants with different
           instruction and register set characteristics.  This flag prevents
           code compiled for one cpu to be linked with code compiled for
           another.  No facility exists for handling variants that are
           ``almost identical''.  This is an all or nothing option.

       -mcpu=cpu
           Compile code for ARC variant cpu.  Which variants are supported
           depend on the configuration.  All variants support -mcpu=base, this
           is the default.

       -mtext=text-section
       -mdata=data-section
       -mrodata=readonly-data-section
           Put functions, data, and readonly data in text-section, data-sec-
           tion, and readonly-data-section respectively by default.  This can
           be overridden with the "section" attribute.

       NS32K Options

       These are the -m options defined for the 32000 series.  The default
       values for these options depends on which style of 32000 was selected
       when the compiler was configured; the defaults for the most common
       choices are given below.

       -m32032
       -m32032
           Generate output for a 32032.  This is the default when the compiler
           is configured for 32032 and 32016 based systems.

       -m32332
       -m32332
           Generate output for a 32332.  This is the default when the compiler
           is configured for 32332-based systems.

       -m32532
       -m32532
           Generate output for a 32532.  This is the default when the compiler
           is configured for 32532-based systems.
           configuration.

       -mmulti-add
           Try and generate multiply-add floating point instructions "polyF"
           and "dotF".  This option is only available if the -m32381 option is
           in effect.  Using these instructions requires changes to register
           allocation which generally has a negative impact on performance.
           This option should only be enabled when compiling code particularly
           likely to make heavy use of multiply-add instructions.

       -mnomulti-add
           Do not try and generate multiply-add floating point instructions
           "polyF" and "dotF".  This is the default on all platforms.

       -msoft-float
           Generate output containing library calls for floating point.  Warn-
           ing: the requisite libraries may not be available.

       -mnobitfield
           Do not use the bit-field instructions.  On some machines it is
           faster to use shifting and masking operations.  This is the default
           for the pc532.

       -mbitfield
           Do use the bit-field instructions.  This is the default for all
           platforms except the pc532.

       -mrtd
           Use a different function-calling convention, in which functions
           that take a fixed number of arguments return pop their arguments on
           return with the "ret" instruction.

           This calling convention is incompatible with the one normally used
           on Unix, so you cannot use it if you need to call libraries com-
           piled with the Unix compiler.

           Also, you must provide function prototypes for all functions that
           take variable numbers of arguments (including "printf"); otherwise
           incorrect code will be generated for calls to those functions.

           In addition, seriously incorrect code will result if you call a
           function with too many arguments.  (Normally, extra arguments are
           harmlessly ignored.)

           This option takes its name from the 680x0 "rtd" instruction.

       -mregparam
           Use a different function-calling convention where the first two
           arguments are passed in registers.

           This calling convention is incompatible with the one normally used
           on Unix, so you cannot use it if you need to call libraries com-
           piled with the Unix compiler.

       -mnoregparam
           Do not pass any arguments in registers.  This is the default for
           all targets.
           -mhimem or -fpic is set.

       -mhimem
           Many ns32000 series addressing modes use displacements of up to
           512MB.  If an address is above 512MB then displacements from zero
           can not be used.  This option causes code to be generated which can
           be loaded above 512MB.  This may be useful for operating systems or
           ROM code.

       -mnohimem
           Assume code will be loaded in the first 512MB of virtual address
           space.  This is the default for all platforms.

       AVR Options

       These options are defined for AVR implementations:

       -mmcu=mcu
           Specify ATMEL AVR instruction set or MCU type.

           Instruction set avr1 is for the minimal AVR core, not supported by
           the C compiler, only for assembler programs (MCU types: at90s1200,
           attiny10, attiny11, attiny12, attiny15, attiny28).

           Instruction set avr2 (default) is for the classic AVR core with up
           to 8K program memory space (MCU types: at90s2313, at90s2323,
           attiny22, at90s2333, at90s2343, at90s4414, at90s4433, at90s4434,
           at90s8515, at90c8534, at90s8535).

           Instruction set avr3 is for the classic AVR core with up to 128K
           program memory space (MCU types: atmega103, atmega603, at43usb320,
           at76c711).

           Instruction set avr4 is for the enhanced AVR core with up to 8K
           program memory space (MCU types: atmega8, atmega83, atmega85).

           Instruction set avr5 is for the enhanced AVR core with up to 128K
           program memory space (MCU types: atmega16, atmega161, atmega163,
           atmega32, atmega323, atmega64, atmega128, at43usb355, at94k).

       -msize
           Output instruction sizes to the asm file.

       -minit-stack=N
           Specify the initial stack address, which may be a symbol or numeric
           value, __stack is the default.

       -mno-interrupts
           Generated code is not compatible with hardware interrupts.  Code
           size will be smaller.

       -mcall-prologues
           Functions prologues/epilogues expanded as call to appropriate sub-
           routines.  Code size will be smaller.

       -mno-tablejump
           Do not generate tablejump insns which sometimes increase code size.

       -mhardlit
       -mno-hardlit
           Inline constants into the code stream if it can be done in two
           instructions or less.

       -mdiv
       -mdiv
       -mno-div
           Use the divide instruction.  (Enabled by default).

       -mrelax-immediate
       -mrelax-immediate
       -mno-relax-immediate
           Allow arbitrary sized immediates in bit operations.

       -mwide-bitfields
       -mwide-bitfields
       -mno-wide-bitfields
           Always treat bit-fields as int-sized.

       -m4byte-functions
       -m4byte-functions
       -mno-4byte-functions
           Force all functions to be aligned to a four byte boundary.

       -mcallgraph-data
       -mcallgraph-data
       -mno-callgraph-data
           Emit callgraph information.

       -mslow-bytes
       -mslow-bytes
       -mno-slow-bytes
           Prefer word access when reading byte quantities.

       -mlittle-endian
       -mlittle-endian
       -mbig-endian
           Generate code for a little endian target.

       -m210
       -m210
       -m340
           Generate code for the 210 processor.

       IA-64 Options

       These are the -m options defined for the Intel IA-64 architecture.

       -mbig-endian
           Generate code for a big endian target.  This is the default for
           HPUX.

       -mlittle-endian
           Generate code for a little endian target.  This is the default for
           AIX5 and Linux.

       -mno-pic
           Generate code that does not use a global pointer register.  The
           result is not position independent code, and violates the IA-64
           ABI.

       -mvolatile-asm-stop
       -mno-volatile-asm-stop
           Generate (or don't) a stop bit immediately before and after
           volatile asm statements.

       -mb-step
           Generate code that works around Itanium B step errata.

       -mregister-names
       -mno-register-names
           Generate (or don't) in, loc, and out register names for the stacked
           registers.  This may make assembler output more readable.

       -mno-sdata
       -msdata
           Disable (or enable) optimizations that use the small data section.
           This may be useful for working around optimizer bugs.

       -mconstant-gp
           Generate code that uses a single constant global pointer value.
           This is useful when compiling kernel code.

       -mauto-pic
           Generate code that is self-relocatable.  This implies -mcon-
           stant-gp.  This is useful when compiling firmware code.

       -minline-divide-min-latency
           Generate code for inline divides using the minimum latency algo-
           rithm.

       -minline-divide-max-throughput
           Generate code for inline divides using the maximum throughput algo-
           rithm.

       -mno-dwarf2-asm
       -mdwarf2-asm
           Don't (or do) generate assembler code for the DWARF2 line number
           debugging info.  This may be useful when not using the GNU assem-
           bler.

       -mfixed-range=register-range
           Generate code treating the given register range as fixed registers.
           A fixed register is one that the register allocator can not use.
           This is useful when compiling kernel code.  A register range is
           specified as two registers separated by a dash.  Multiple register
           ranges can be specified separated by a comma.

       D30V Options

       These -m options are defined for D30V implementations:

       -mextmem
           .data1 sections into onchip data memory, which starts at location
           0x20000000.

       -mno-asm-optimize
       -masm-optimize
           Disable (enable) passing -O to the assembler when optimizing.  The
           assembler uses the -O option to automatically parallelize adjacent
           short instructions where possible.

       -mbranch-cost=n
           Increase the internal costs of branches to n.  Higher costs means
           that the compiler will issue more instructions to avoid doing a
           branch.  The default is 2.

       -mcond-exec=n
           Specify the maximum number of conditionally executed instructions
           that replace a branch.  The default is 4.

       S/390 and zSeries Options

       These are the -m options defined for the S/390 and zSeries architec-
       ture.

       -mhard-float
       -msoft-float
           Use (do not use) the hardware floating-point instructions and reg-
           isters for floating-point operations.  When -msoft-float is speci-
           fied, functions in libgcc.a will be used to perform floating-point
           operations.  When -mhard-float is specified, the compiler generates
           IEEE floating-point instructions.  This is the default.

       -mbackchain
       -mno-backchain
           Generate (or do not generate) code which maintains an explicit
           backchain within the stack frame that points to the caller's frame.
           This is currently needed to allow debugging.  The default is to
           generate the backchain.

       -msmall-exec
       -mno-small-exec
           Generate (or do not generate) code using the "bras" instruction to
           do subroutine calls.  This only works reliably if the total exe-
           cutable size does not exceed 64k.  The default is to use the "basr"
           instruction instead, which does not have this limitation.

       -m64
       -m31
           When -m31 is specified, generate code compliant to the Linux for
           S/390 ABI.  When -m64 is specified, generate code compliant to the
           Linux for zSeries ABI.  This allows GCC in particular to generate
           64-bit instructions.  For the s390 targets, the default is -m31,
           while the s390x targets default to -m64.

       -mmvcle
       -mno-mvcle
           Generate (or do not generate) code using the "mvcle" instruction to
           perform block moves.  When -mno-mvcle is specifed, use a "mvc" loop

       These options are defined specifically for the CRIS ports.

       -march=architecture-type
       -mcpu=architecture-type
           Generate code for the specified architecture.  The choices for
           architecture-type are v3, v8 and v10 for respectively ETRAX 4,
           ETRAX 100, and ETRAX 100 LX.  Default is v0 except for
           cris-axis-linux-gnu, where the default is v10.

       -mtune=architecture-type
           Tune to architecture-type everything applicable about the generated
           code, except for the ABI and the set of available instructions.
           The choices for architecture-type are the same as for -march=archi-
           tecture-type.

       -mmax-stack-frame=n
           Warn when the stack frame of a function exceeds n bytes.

       -melinux-stacksize=n
           Only available with the cris-axis-aout target.  Arranges for indi-
           cations in the program to the kernel loader that the stack of the
           program should be set to n bytes.

       -metrax4
       -metrax100
           The options -metrax4 and -metrax100 are synonyms for -march=v3 and
           -march=v8 respectively.

       -mpdebug
           Enable CRIS-specific verbose debug-related information in the
           assembly code.  This option also has the effect to turn off the
           #NO_APP formatted-code indicator to the assembler at the beginning
           of the assembly file.

       -mcc-init
           Do not use condition-code results from previous instruction; always
           emit compare and test instructions before use of condition codes.

       -mno-side-effects
           Do not emit instructions with side-effects in addressing modes
           other than post-increment.

       -mstack-align
       -mno-stack-align
       -mdata-align
       -mno-data-align
       -mconst-align
       -mno-const-align
           These options (no-options) arranges (eliminate arrangements) for
           the stack-frame, individual data and constants to be aligned for
           the maximum single data access size for the chosen CPU model.  The
           default is to arrange for 32-bit alignment.  ABI details such as
           structure layout are not affected by these options.

       -m32-bit
       -m16-bit
       -m8-bit
           instructions or return sequences are generated in the code.  Use
           this option only together with visual inspection of the compiled
           code: no warnings or errors are generated when call-saved registers
           must be saved, or storage for local variable needs to be allocated.

       -mno-gotplt
       -mgotplt
           With -fpic and -fPIC, don't generate (do generate) instruction
           sequences that load addresses for functions from the PLT part of
           the GOT rather than (traditional on other architectures) calls to
           the PLT.  The default is -mgotplt.

       -maout
           Legacy no-op option only recognized with the cris-axis-aout target.

       -melf
           Legacy no-op option only recognized with the cris-axis-elf and
           cris-axis-linux-gnu targets.

       -melinux
           Only recognized with the cris-axis-aout target, where it selects a
           GNU/linux-like multilib, include files and instruction set for
           -march=v8.

       -mlinux
           Legacy no-op option only recognized with the cris-axis-linux-gnu
           target.

       -sim
           This option, recognized for the cris-axis-aout and cris-axis-elf
           arranges to link with input-output functions from a simulator
           library.  Code, initialized data and zero-initialized data are
           allocated consecutively.

       -sim2
           Like -sim, but pass linker options to locate initialized data at
           0x40000000 and zero-initialized data at 0x80000000.

       MMIX Options

       These options are defined for the MMIX:

       -mlibfuncs
       -mno-libfuncs
           Specify that intrinsic library functions are being compiled, pass-
           ing all values in registers, no matter the size.

       -mepsilon
       -mno-epsilon
           Generate floating-point comparison instructions that compare with
           respect to the "rE" epsilon register.

       -mabi=mmixware
       -mabi=gnu
           Generate code that passes function parameters and return values
           that (in the called function) are seen as registers $0 and up, as
           opposed to the GNU ABI which uses global registers $231 and up.
           Make the result of a division yielding a remainder have the same
           sign as the divisor.  With the default, -mno-knuthdiv, the sign of
           the remainder follows the sign of the dividend.  Both methods are
           arithmetically valid, the latter being almost exclusively used.

       -mtoplevel-symbols
       -mno-toplevel-symbols
           Prepend (do not prepend) a : to all global symbols, so the assembly
           code can be used with the "PREFIX" assembly directive.

       -melf
           Generate an executable in the ELF format, rather than the default
           mmo format used by the mmix simulator.

       -mbranch-predict
       -mno-branch-predict
           Use (do not use) the probable-branch instructions, when static
           branch prediction indicates a probable branch.

       -mbase-addresses
       -mno-base-addresses
           Generate (do not generate) code that uses base addresses.  Using a
           base address automatically generates a request (handled by the
           assembler and the linker) for a constant to be set up in a global
           register.  The register is used for one or more base address
           requests within the range 0 to 255 from the value held in the reg-
           ister.  The generally leads to short and fast code, but the number
           of different data items that can be addressed is limited.  This
           means that a program that uses lots of static data may require
           -mno-base-addresses.

       PDP-11 Options

       These options are defined for the PDP-11:

       -mfpu
           Use hardware FPP floating point.  This is the default.  (FIS float-
           ing point on the PDP-11/40 is not supported.)

       -msoft-float
           Do not use hardware floating point.

       -mac0
           Return floating-point results in ac0 (fr0 in Unix assembler syn-
           tax).

       -mno-ac0
           Return floating-point results in memory.  This is the default.

       -m40
           Generate code for a PDP-11/40.

       -m45
           Generate code for a PDP-11/45.  This is the default.

       -m10
           Generate code for a PDP-11/10.

       -mno-int32
           Use 16-bit "int".  This is the default.

       -mint32
       -mno-int16
           Use 32-bit "int".

       -mfloat64
       -mno-float32
           Use 64-bit "float".  This is the default.

       -mfloat32
       -mno-float64
           Use 32-bit "float".

       -mabshi
           Use "abshi2" pattern.  This is the default.

       -mno-abshi
           Do not use "abshi2" pattern.

       -mbranch-expensive
           Pretend that branches are expensive.  This is for experimenting
           with code generation only.

       -mbranch-cheap
           Do not pretend that branches are expensive.  This is the default.

       -msplit
           Generate code for a system with split I&D.

       -mno-split
           Generate code for a system without split I&D.  This is the default.

       -munix-asm
           Use Unix assembler syntax.  This is the default when configured for
           pdp11-*-bsd.

       -mdec-asm
           Use DEC assembler syntax.  This is the default when configured for
           any PDP-11 target other than pdp11-*-bsd.

       Xstormy16 Options

       These options are defined for Xstormy16:

       -msim
           Choose startup files and linker script suitable for the simulator.

       Xtensa Options

       The Xtensa architecture is designed to support many different configu-
       rations.  The compiler's default options can be set to match a particu-
       lar Xtensa configuration by copying a configuration file into the GCC
       sources when building GCC.  The options below may be used to override
       the default options.


       -mmac16
       -mno-mac16
           Enable or disable use of the Xtensa MAC16 option.  When enabled,
           GCC will generate MAC16 instructions from standard C code, with the
           limitation that it will use neither the MR register file nor any
           instruction that operates on the MR registers.  When this option is
           disabled, GCC will translate 16-bit multiply/accumulate operations
           to a combination of core instructions and library calls, depending
           on whether any other multiplier options are enabled.

       -mmul16
       -mno-mul16
           Enable or disable use of the 16-bit integer multiplier option.
           When enabled, the compiler will generate 16-bit multiply instruc-
           tions for multiplications of 16 bits or smaller in standard C code.
           When this option is disabled, the compiler will either use 32-bit
           multiply or MAC16 instructions if they are available or generate
           library calls to perform the multiply operations using shifts and
           adds.

       -mmul32
       -mno-mul32
           Enable or disable use of the 32-bit integer multiplier option.
           When enabled, the compiler will generate 32-bit multiply instruc-
           tions for multiplications of 32 bits or smaller in standard C code.
           When this option is disabled, the compiler will generate library
           calls to perform the multiply operations using either shifts and
           adds or 16-bit multiply instructions if they are available.

       -mnsa
       -mno-nsa
           Enable or disable use of the optional normalization shift amount
           ("NSA") instructions to implement the built-in "ffs" function.

       -mminmax
       -mno-minmax
           Enable or disable use of the optional minimum and maximum value
           instructions.

       -msext
       -mno-sext
           Enable or disable use of the optional sign extend ("SEXT") instruc-
           tion.

       -mbooleans
       -mno-booleans
           Enable or disable support for the boolean register file used by
           Xtensa coprocessors.  This is not typically useful by itself but
           may be required for other options that make use of the boolean reg-
           isters (e.g., the floating-point option).

       -mhard-float
       -msoft-float
           Enable or disable use of the floating-point option.  When enabled,
           GCC generates floating-point instructions for 32-bit "float" opera-
           tions.  When this option is disabled, GCC generates library calls
           multiply/add and multiply/subtract instructions forces the compiler
           to use separate instructions for the multiply and add/subtract
           operations.  This may be desirable in some cases where strict IEEE
           754-compliant results are required: the fused multiply add/subtract
           instructions do not round the intermediate result, thereby produc-
           ing results with more bits of precision than specified by the IEEE
           standard.  Disabling fused multiply add/subtract instructions also
           ensures that the program output is not sensitive to the compiler's
           ability to combine multiply and add/subtract operations.

       -mserialize-volatile
       -mno-serialize-volatile
           When this option is enabled, GCC inserts "MEMW" instructions before
           "volatile" memory references to guarantee sequential consistency.
           The default is -mserialize-volatile.  Use -mno-serialize-volatile
           to omit the "MEMW" instructions.

       -mtext-section-literals
       -mno-text-section-literals
           Control the treatment of literal pools.  The default is
           -mno-text-section-literals, which places literals in a separate
           section in the output file.  This allows the literal pool to be
           placed in a data RAM/ROM, and it also allows the linker to combine
           literal pools from separate object files to remove redundant liter-
           als and improve code size.  With -mtext-section-literals, the lit-
           erals are interspersed in the text section in order to keep them as
           close as possible to their references.  This may be necessary for
           large assembly files.

       -mtarget-align
       -mno-target-align
           When this option is enabled, GCC instructs the assembler to auto-
           matically align instructions to reduce branch penalties at the
           expense of some code density.  The assembler attempts to widen den-
           sity instructions to align branch targets and the instructions fol-
           lowing call instructions.  If there are not enough preceding safe
           density instructions to align a target, no widening will be per-
           formed.  The default is -mtarget-align.  These options do not
           affect the treatment of auto-aligned instructions like "LOOP",
           which the assembler will always align, either by widening density
           instructions or by inserting no-op instructions.

       -mlongcalls
       -mno-longcalls
           When this option is enabled, GCC instructs the assembler to trans-
           late direct calls to indirect calls unless it can determine that
           the target of a direct call is in the range allowed by the call
           instruction.  This translation typically occurs for calls to func-
           tions in other source files.  Specifically, the assembler trans-
           lates a direct "CALL" instruction into an "L32R" followed by a
           "CALLX" instruction.  The default is -mno-longcalls.  This option
           should be used in programs where the call target can potentially be
           out of range.  This option is implemented in the assembler, not the
           compiler, so the assembly code generated by GCC will still show
           direct call instructions---look at the disassembled object code to
           see the actual instructions.  Note that the assembler will use an
           indirect call for every cross-file call, not just those that really

       is listed---the one which is not the default.  You can figure out the
       other form by either removing no- or adding it.

       -fexceptions
           Enable exception handling.  Generates extra code needed to propa-
           gate exceptions.  For some targets, this implies GCC will generate
           frame unwind information for all functions, which can produce sig-
           nificant data size overhead, although it does not affect execution.
           If you do not specify this option, GCC will enable it by default
           for languages like C++ which normally require exception handling,
           and disable it for languages like C that do not normally require
           it.  However, you may need to enable this option when compiling C
           code that needs to interoperate properly with exception handlers
           written in C++.  You may also wish to disable this option if you
           are compiling older C++ programs that don't use exception handling.

       -fnon-call-exceptions
           Generate code that allows trapping instructions to throw excep-
           tions.  Note that this requires platform-specific runtime support
           that does not exist everywhere.  Moreover, it only allows trapping
           instructions to throw exceptions, i.e. memory references or float-
           ing point instructions.  It does not allow exceptions to be thrown
           from arbitrary signal handlers such as "SIGALRM".

       -funwind-tables
           Similar to -fexceptions, except that it will just generate any
           needed static data, but will not affect the generated code in any
           other way.  You will normally not enable this option; instead, a
           language processor that needs this handling would enable it on your
           behalf.

       -fasynchronous-unwind-tables
           Generate unwind table in dwarf2 format, if supported by target
           machine.  The table is exact at each instruction boundary, so it
           can be used for stack unwinding from asynchronous events (such as
           debugger or garbage collector).

       -fpcc-struct-return
           Return ``short'' "struct" and "union" values in memory like longer
           ones, rather than in registers.  This convention is less efficient,
           but it has the advantage of allowing intercallability between GCC-
           compiled files and files compiled with other compilers, particu-
           larly the Portable C Compiler (pcc).

           The precise convention for returning structures in memory depends
           on the target configuration macros.

           Short structures and unions are those whose size and alignment
           match that of some integer type.

           Warning: code compiled with the -fpcc-struct-return switch is not
           binary compatible with code compiled with the -freg-struct-return
           switch.  Use it to conform to a non-default application binary
           interface.

       -freg-struct-return
           Return "struct" and "union" values in registers when possible.

           Warning: code compiled with the -freg-struct-return switch is not
           binary compatible with code compiled with the -fpcc-struct-return
           switch.  Use it to conform to a non-default application binary
           interface.

       -fshort-enums
           Allocate to an "enum" type only as many bytes as it needs for the
           declared range of possible values.  Specifically, the "enum" type
           will be equivalent to the smallest integer type which has enough
           room.

           Warning: the -fshort-enums switch causes GCC to generate code that
           is not binary compatible with code generated without that switch.
           Use it to conform to a non-default application binary interface.

       -fshort-double
           Use the same size for "double" as for "float".

           Warning: the -fshort-double switch causes GCC to generate code that
           is not binary compatible with code generated without that switch.
           Use it to conform to a non-default application binary interface.

       -fshort-wchar
           Override the underlying type for wchar_t to be short unsigned int
           instead of the default for the target.  This option is useful for
           building programs to run under WINE.

           Warning: the -fshort-wchar switch causes GCC to generate code that
           is not binary compatible with code generated without that switch.
           Use it to conform to a non-default application binary interface.

       -fshared-data
           Requests that the data and non-"const" variables of this compila-
           tion be shared data rather than private data.  The distinction
           makes sense only on certain operating systems, where shared data is
           shared between processes running the same program, while private
           data exists in one copy per process.

       -fno-common
           In C, allocate even uninitialized global variables in the data sec-
           tion of the object file, rather than generating them as common
           blocks.  This has the effect that if the same variable is declared
           (without "extern") in two different compilations, you will get an
           error when you link them.  The only reason this might be useful is
           if you wish to verify that the program will work on other systems
           which always work this way.

       -fno-ident
           Ignore the #ident directive.

       -fno-gnu-linker
           Do not output global initializations (such as C++ constructors and
           destructors) in the form used by the GNU linker (on systems where
           the GNU linker is the standard method of handling them).  Use this
           option when you want to use a non-GNU linker, which also requires
           using the collect2 program to make sure the system linker includes
           use it for anything else.

       -fverbose-asm
           Put extra commentary information in the generated assembly code to
           make it more readable.  This option is generally only of use to
           those who actually need to read the generated assembly code (per-
           haps while debugging the compiler itself).

           -fno-verbose-asm, the default, causes the extra information to be
           omitted and is useful when comparing two assembler files.

       -fvolatile
           Consider all memory references through pointers to be volatile.

       -fvolatile-global
           Consider all memory references to extern and global data items to
           be volatile.  GCC does not consider static data items to be
           volatile because of this switch.

       -fvolatile-static
           Consider all memory references to static data to be volatile.

       -fpic
           Generate position-independent code (PIC) suitable for use in a
           shared library, if supported for the target machine.  Such code
           accesses all constant addresses through a global offset table
           (GOT).  The dynamic loader resolves the GOT entries when the pro-
           gram starts (the dynamic loader is not part of GCC; it is part of
           the operating system).  If the GOT size for the linked executable
           exceeds a machine-specific maximum size, you get an error message
           from the linker indicating that -fpic does not work; in that case,
           recompile with -fPIC instead.  (These maximums are 16k on the m88k,
           8k on the Sparc, and 32k on the m68k and RS/6000.  The 386 has no
           such limit.)

           Position-independent code requires special support, and therefore
           works only on certain machines.  For the 386, GCC supports PIC for
           System V but not for the Sun 386i.  Code generated for the IBM
           RS/6000 is always position-independent.

       -fPIC
           If supported for the target machine, emit position-independent
           code, suitable for dynamic linking and avoiding any limit on the
           size of the global offset table.  This option makes a difference on
           the m68k, m88k, and the Sparc.

           Position-independent code requires special support, and therefore
           works only on certain machines.

       -ffixed-reg
           Treat the register named reg as a fixed register; generated code
           should never refer to it (except perhaps as a stack pointer, frame
           pointer or in some other fixed role).

           reg must be the name of a register.  The register names accepted
           are machine-specific and are defined in the "REGISTER_NAMES" macro
           in the machine description macro file.

           It is an error to used this flag with the frame pointer or stack
           pointer.  Use of this flag for other registers that have fixed per-
           vasive roles in the machine's execution model will produce disas-
           trous results.

           This flag does not have a negative form, because it specifies a
           three-way choice.

       -fcall-saved-reg
           Treat the register named reg as an allocable register saved by
           functions.  It may be allocated even for temporaries or variables
           that live across a call.  Functions compiled this way will save and
           restore the register reg if they use it.

           It is an error to used this flag with the frame pointer or stack
           pointer.  Use of this flag for other registers that have fixed per-
           vasive roles in the machine's execution model will produce disas-
           trous results.

           A different sort of disaster will result from the use of this flag
           for a register in which function values may be returned.

           This flag does not have a negative form, because it specifies a
           three-way choice.

       -fpack-struct
           Pack all structure members together without holes.

           Warning: the -fpack-struct switch causes GCC to generate code that
           is not binary compatible with code generated without that switch.
           Additionally, it makes the code suboptimial.  Use it to conform to
           a non-default application binary interface.

       -finstrument-functions
           Generate instrumentation calls for entry and exit to functions.
           Just after function entry and just before function exit, the fol-
           lowing profiling functions will be called with the address of the
           current function and its call site.  (On some platforms,
           "__builtin_return_address" does not work beyond the current func-
           tion, so the call site information may not be available to the pro-
           filing functions otherwise.)

                   void __cyg_profile_func_enter (void *this_fn,
                                                  void *call_site);
                   void __cyg_profile_func_exit  (void *this_fn,
                                                  void *call_site);

           The first argument is the address of the start of the current func-
           tion, which may be looked up exactly in the symbol table.

           This instrumentation is also done for functions expanded inline in
           other functions.  The profiling calls will indicate where, concep-
           tually, the inline function is entered and exited.  This means that
           addressable versions of such functions must be available.  If all
           your uses of a function are expanded inline, this may mean an
           additional expansion of code size.  If you use extern inline in
           filing functions cannot safely be called (perhaps signal handlers,
           if the profiling routines generate output or allocate memory).

       -fstack-check
           Generate code to verify that you do not go beyond the boundary of
           the stack.  You should specify this flag if you are running in an
           environment with multiple threads, but only rarely need to specify
           it in a single-threaded environment since stack overflow is auto-
           matically detected on nearly all systems if there is only one
           stack.

           Note that this switch does not actually cause checking to be done;
           the operating system must do that.  The switch causes generation of
           code to ensure that the operating system sees the stack being
           extended.

       -fstack-limit-register=reg
       -fstack-limit-symbol=sym
       -fno-stack-limit
           Generate code to ensure that the stack does not grow beyond a cer-
           tain value, either the value of a register or the address of a sym-
           bol.  If the stack would grow beyond the value, a signal is raised.
           For most targets, the signal is raised before the stack overruns
           the boundary, so it is possible to catch the signal without taking
           special precautions.

           For instance, if the stack starts at absolute address 0x80000000
           and grows downwards, you can use the flags -fstack-limit-sym-
           bol=__stack_limit and -Wl,--defsym,__stack_limit=0x7ffe0000 to
           enforce a stack limit of 128KB.  Note that this may only work with
           the GNU linker.

       -fargument-alias
       -fargument-noalias
       -fargument-noalias-global
           Specify the possible relationships among parameters and between
           parameters and global data.

           -fargument-alias specifies that arguments (parameters) may alias
           each other and may alias global storage.-fargument-noalias speci-
           fies that arguments do not alias each other, but may alias global
           storage.-fargument-noalias-global specifies that arguments do not
           alias each other and do not alias global storage.

           Each language will automatically use whatever option is required by
           the language standard.  You should not need to use these options
           yourself.

       -fleading-underscore
           This option and its counterpart, -fno-leading-underscore, forcibly
           change the way C symbols are represented in the object file.  One
           use is to help link with legacy assembly code.

           Warning: the -fleading-underscore switch causes GCC to generate
           code that is not binary compatible with code generated without that
           switch.  Use it to conform to a non-default application binary
           interface.  Not all targets provide complete support for this


ENVIRONMENT

       This section describes several environment variables that affect how
       GCC operates.  Some of them work by specifying directories or prefixes
       to use when searching for various kinds of files.  Some are used to
       specify other aspects of the compilation environment.

       Note that you can also specify places to search using options such as
       -B, -I and -L.  These take precedence over places specified using envi-
       ronment variables, which in turn take precedence over those specified
       by the configuration of GCC.

       LANG
       LC_CTYPE
       LC_MESSAGES
       LC_ALL
           These environment variables control the way that GCC uses localiza-
           tion information that allow GCC to work with different national
           conventions.  GCC inspects the locale categories LC_CTYPE and
           LC_MESSAGES if it has been configured to do so.  These locale cate-
           gories can be set to any value supported by your installation.  A
           typical value is en_UK for English in the United Kingdom.

           The LC_CTYPE environment variable specifies character classifica-
           tion.  GCC uses it to determine the character boundaries in a
           string; this is needed for some multibyte encodings that contain
           quote and escape characters that would otherwise be interpreted as
           a string end or escape.

           The LC_MESSAGES environment variable specifies the language to use
           in diagnostic messages.

           If the LC_ALL environment variable is set, it overrides the value
           of LC_CTYPE and LC_MESSAGES; otherwise, LC_CTYPE and LC_MESSAGES
           default to the value of the LANG environment variable.  If none of
           these variables are set, GCC defaults to traditional C English
           behavior.

       TMPDIR
           If TMPDIR is set, it specifies the directory to use for temporary
           files.  GCC uses temporary files to hold the output of one stage of
           compilation which is to be used as input to the next stage: for
           example, the output of the preprocessor, which is the input to the
           compiler proper.

       GCC_EXEC_PREFIX
           If GCC_EXEC_PREFIX is set, it specifies a prefix to use in the
           names of the subprograms executed by the compiler.  No slash is
           added when this prefix is combined with the name of a subprogram,
           but you can specify a prefix that ends with a slash if you wish.

           If GCC_EXEC_PREFIX is not set, GCC will attempt to figure out an
           appropriate prefix to use based on the pathname it was invoked
           with.

           If GCC cannot find the subprogram using the specified prefix, it
           tries looking in the usual places for the subprogram.
           In addition, the prefix is used in an unusual way in finding the
           directories to search for header files.  For each of the standard
           directories whose name normally begins with /usr/local/lib/gcc-lib
           (more precisely, with the value of GCC_INCLUDE_DIR), GCC tries
           replacing that beginning with the specified prefix to produce an
           alternate directory name.  Thus, with -Bfoo/, GCC will search
           foo/bar where it would normally search /usr/local/lib/bar.  These
           alternate directories are searched first; the standard directories
           come next.

       COMPILER_PATH
           The value of COMPILER_PATH is a colon-separated list of directo-
           ries, much like PATH.  GCC tries the directories thus specified
           when searching for subprograms, if it can't find the subprograms
           using GCC_EXEC_PREFIX.

       LIBRARY_PATH
           The value of LIBRARY_PATH is a colon-separated list of directories,
           much like PATH.  When configured as a native compiler, GCC tries
           the directories thus specified when searching for special linker
           files, if it can't find them using GCC_EXEC_PREFIX.  Linking using
           GCC also uses these directories when searching for ordinary
           libraries for the -l option (but directories specified with -L come
           first).

       LANG
           This variable is used to pass locale information to the compiler.
           One way in which this information is used is to determine the char-
           acter set to be used when character literals, string literals and
           comments are parsed in C and C++.  When the compiler is configured
           to allow multibyte characters, the following values for LANG are
           recognized:

           C-JIS
               Recognize JIS characters.

           C-SJIS
               Recognize SJIS characters.

           C-EUCJP
               Recognize EUCJP characters.

           If LANG is not defined, or if it has some other value, then the
           compiler will use mblen and mbtowc as defined by the default locale
           to recognize and translate multibyte characters.

       Some additional environments variables affect the behavior of the pre-
       processor.

       CPATH
       C_INCLUDE_PATH
       CPLUS_INCLUDE_PATH
       OBJC_INCLUDE_PATH
           Each variable's value is a list of directories separated by a spe-
           cial character, much like PATH, in which to look for header files.
           The special character, "PATH_SEPARATOR", is target-dependent and
           determined at GCC build time.  For Windows-based targets it is a
           tories to be searched as if specified with -isystem, but after any
           paths given with -isystem options on the command line.

       DEPENDENCIES_OUTPUT
           @anchor{DEPENDENCIES_OUTPUT} If this variable is set, its value
           specifies how to output dependencies for Make based on the non-sys-
           tem header files processed by the compiler.  System header files
           are ignored in the dependency output.

           The value of DEPENDENCIES_OUTPUT can be just a file name, in which
           case the Make rules are written to that file, guessing the target
           name from the source file name.  Or the value can have the form
           file target, in which case the rules are written to file file using
           target as the target name.

           In other words, this environment variable is equivalent to combin-
           ing the options -MM and -MF, with an optional -MT switch too.

       SUNPRO_DEPENDENCIES
           This variable is the same as the environment variable DEPENDEN-
           CIES_OUTPUT, except that system header files are not ignored, so it
           implies -M rather than -MM.  However, the dependence on the main
           input file is omitted.


BUGS

       For instructions on reporting bugs, see <http://gcc.gnu.org/bugs.html>.
       Use of the gccbug script to report bugs is recommended.


FOOTNOTES

       1.  On some systems, gcc -shared needs to build supplementary stub code
           for constructors to work.  On multi-libbed systems, gcc -shared
           must select the correct support libraries to link against.  Failing
           to supply the correct flags may lead to subtle defects.  Supplying
           them in cases where they are not necessary is innocuous.


SEE ALSO

       gpl(7), gfdl(7), fsf-funding(7), cpp(1), gcov(1), g77(1), as(1), ld(1),
       gdb(1), adb(1), dbx(1), sdb(1) and the Info entries for gcc, cpp, g77,
       as, ld, binutils and gdb.


AUTHOR

       See the Info entry for gcc, or <http://gcc.gnu.org/onlinedocs/gcc/Con-
       tributors.html>, for contributors to GCC.


COPYRIGHT

       Copyright (c) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
       1999, 2000, 2001, 2002, 2003 Free Software Foundation, Inc.

       Permission is granted to copy, distribute and/or modify this document
       under the terms of the GNU Free Documentation License, Version 1.1 or
       any later version published by the Free Software Foundation; with the
       Invariant Sections being ``GNU General Public License'' and ``Funding
       Free Software'', the Front-Cover texts being (a) (see below), and with
       the Back-Cover Texts being (b) (see below).  A copy of the license is
       included in the gfdl(7) man page.

       (a) The FSF's Front-Cover Text is:

gcc-3.2.2                         2003-02-25                            gcc(1)