@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
-@c 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008
+@c 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
@c Free Software Foundation, Inc.
@c This is part of the GCC manual.
@c For copying conditions, see the file gcc.texi.
@c man begin COPYRIGHT
Copyright @copyright{} 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
-1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008
+1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
Free Software Foundation, Inc.
Permission is granted to copy, distribute and/or modify this document
and register usage.
* Environment Variables:: Env vars that affect GCC.
* Precompiled Headers:: Compiling a header once, and using it many times.
-* Running Protoize:: Automatically adding or removing function prototypes.
@end menu
@c man begin OPTIONS
@table @emph
@item Overall Options
@xref{Overall Options,,Options Controlling the Kind of Output}.
-@gccoptlist{-c -S -E -o @var{file} -combine -pipe -pass-exit-codes @gol
--x @var{language} -v -### --help@r{[}=@var{class}@r{]} --target-help @gol
---version -wrapper@@@var{file}}
+@gccoptlist{-c -S -E -o @var{file} -combine -no-canonical-prefixes @gol
+-pipe -pass-exit-codes @gol
+-x @var{language} -v -### --help@r{[}=@var{class}@r{[},@dots{}@r{]]} --target-help @gol
+--version -wrapper@@@var{file} -fplugin=@var{file} -fplugin-arg-@var{name}=@var{arg}}
@item C Language Options
@xref{C Dialect Options,,Options Controlling C Dialect}.
-fno-implement-inlines -fms-extensions @gol
-fno-nonansi-builtins -fno-operator-names @gol
-fno-optional-diags -fpermissive @gol
+-fno-pretty-templates @gol
-frepo -fno-rtti -fstats -ftemplate-depth-@var{n} @gol
-fno-threadsafe-statics -fuse-cxa-atexit -fno-weak -nostdinc++ @gol
-fno-default-inline -fvisibility-inlines-hidden @gol
-Wchar-subscripts -Wclobbered -Wcomment @gol
-Wconversion -Wcoverage-mismatch -Wno-deprecated @gol
-Wno-deprecated-declarations -Wdisabled-optimization @gol
--Wdisallowed-function-list=@var{sym},@var{sym},@dots{} @gol
-Wno-div-by-zero -Wempty-body -Wenum-compare -Wno-endif-labels @gol
-Werror -Werror=* @gol
-Wfatal-errors -Wfloat-equal -Wformat -Wformat=2 @gol
-Wno-format-contains-nul -Wno-format-extra-args -Wformat-nonliteral @gol
-Wformat-security -Wformat-y2k @gol
--Wframe-larger-than=@var{len} -Wignored-qualifiers @gol
+-Wframe-larger-than=@var{len} -Wjump-misses-init -Wignored-qualifiers @gol
-Wimplicit -Wimplicit-function-declaration -Wimplicit-int @gol
-Winit-self -Winline @gol
-Wno-int-to-pointer-cast -Wno-invalid-offsetof @gol
-Wswitch -Wswitch-default -Wswitch-enum -Wsync-nand @gol
-Wsystem-headers -Wtrigraphs -Wtype-limits -Wundef -Wuninitialized @gol
-Wunknown-pragmas -Wno-pragmas -Wunreachable-code @gol
--Wunused -Wunused-function -Wunused-label -Wunused-parameter @gol
--Wunused-value -Wunused-variable @gol
+-Wunsuffixed-float-constants -Wunused -Wunused-function @gol
+-Wunused-label -Wunused-parameter -Wno-unused-result -Wunused-value -Wunused-variable @gol
-Wvariadic-macros -Wvla @gol
-Wvolatile-register-var -Wwrite-strings}
@xref{Debugging Options,,Options for Debugging Your Program or GCC}.
@gccoptlist{-d@var{letters} -dumpspecs -dumpmachine -dumpversion @gol
-fdbg-cnt-list -fdbg-cnt=@var{counter-value-list} @gol
--fdump-noaddr -fdump-unnumbered @gol
+-fdump-noaddr -fdump-unnumbered -fdump-unnumbered-links @gol
-fdump-translation-unit@r{[}-@var{n}@r{]} @gol
-fdump-class-hierarchy@r{[}-@var{n}@r{]} @gol
-fdump-ipa-all -fdump-ipa-cgraph -fdump-ipa-inline @gol
-fdump-tree-gimple@r{[}-raw@r{]} -fdump-tree-mudflap@r{[}-@var{n}@r{]} @gol
-fdump-tree-dom@r{[}-@var{n}@r{]} @gol
-fdump-tree-dse@r{[}-@var{n}@r{]} @gol
+-fdump-tree-phiprop@r{[}-@var{n}@r{]} @gol
-fdump-tree-phiopt@r{[}-@var{n}@r{]} @gol
-fdump-tree-forwprop@r{[}-@var{n}@r{]} @gol
-fdump-tree-copyrename@r{[}-@var{n}@r{]} @gol
-fdump-tree-nrv -fdump-tree-vect @gol
-fdump-tree-sink @gol
-fdump-tree-sra@r{[}-@var{n}@r{]} @gol
+-fdump-tree-forwprop@r{[}-@var{n}@r{]} @gol
-fdump-tree-fre@r{[}-@var{n}@r{]} @gol
-fdump-tree-vrp@r{[}-@var{n}@r{]} @gol
-ftree-vectorizer-verbose=@var{n} @gol
-fdump-tree-storeccp@r{[}-@var{n}@r{]} @gol
+-fdump-final-insns=@var{file} @gol
+-fcompare-debug@r{[}=@var{opts}@r{]} -fcompare-debug-second @gol
-feliminate-dwarf2-dups -feliminate-unused-debug-types @gol
-feliminate-unused-debug-symbols -femit-class-debug-always @gol
-fmem-report -fpre-ipa-mem-report -fpost-ipa-mem-report -fprofile-arcs @gol
-frandom-seed=@var{string} -fsched-verbose=@var{n} @gol
-fsel-sched-verbose -fsel-sched-dump-cfg -fsel-sched-pipelining-verbose @gol
-ftest-coverage -ftime-report -fvar-tracking @gol
--g -g@var{level} -gcoff -gdwarf-2 @gol
+-g -g@var{level} -gtoggle -gcoff -gdwarf-@var{version} @gol
-ggdb -gstabs -gstabs+ -gvms -gxcoff -gxcoff+ @gol
-fno-merge-debug-strings -fno-dwarf2-cfi-asm @gol
-fdebug-prefix-map=@var{old}=@var{new} @gol
-print-multi-directory -print-multi-lib @gol
-print-prog-name=@var{program} -print-search-dirs -Q @gol
-print-sysroot -print-sysroot-headers-suffix @gol
--save-temps -time}
+-save-temps -save-temps=cwd -save-temps=obj -time@r{[}=@var{file}@r{]}}
@item Optimization Options
@xref{Optimize Options,,Options that Control Optimization}.
-fdata-sections -fdce -fdce @gol
-fdelayed-branch -fdelete-null-pointer-checks -fdse -fdse @gol
-fearly-inlining -fexpensive-optimizations -ffast-math @gol
--ffinite-math-only -ffloat-store -fforward-propagate @gol
--ffunction-sections -fgcse -fgcse-after-reload -fgcse-las -fgcse-lm @gol
+-ffinite-math-only -ffloat-store -fexcess-precision=@var{style} @gol
+-fforward-propagate -ffunction-sections @gol
+-fgcse -fgcse-after-reload -fgcse-las -fgcse-lm @gol
-fgcse-sm -fif-conversion -fif-conversion2 -findirect-inlining @gol
-finline-functions -finline-functions-called-once -finline-limit=@var{n} @gol
--finline-small-functions -fipa-cp -fipa-cp-clone -fipa-matrix-reorg -fipa-pta @gol
+-finline-small-functions -fipa-cp -fipa-cp-clone -fipa-matrix-reorg -fipa-pta @gol
-fipa-pure-const -fipa-reference -fipa-struct-reorg @gol
--fipa-type-escape -fira -fira-algorithm=@var{algorithm} @gol
+-fipa-type-escape -fira-algorithm=@var{algorithm} @gol
-fira-region=@var{region} -fira-coalesce -fno-ira-share-save-slots @gol
-fno-ira-share-spill-slots -fira-verbose=@var{n} @gol
-fivopts -fkeep-inline-functions -fkeep-static-consts @gol
--floop-block -floop-interchange -floop-strip-mine @gol
+-floop-block -floop-interchange -floop-strip-mine -fgraphite-identity @gol
+-floop-parallelize-all @gol
-fmerge-all-constants -fmerge-constants -fmodulo-sched @gol
-fmodulo-sched-allow-regmoves -fmove-loop-invariants -fmudflap @gol
-fmudflapir -fmudflapth -fno-branch-count-reg -fno-default-inline @gol
-freciprocal-math -fregmove -frename-registers -freorder-blocks @gol
-freorder-blocks-and-partition -freorder-functions @gol
-frerun-cse-after-loop -freschedule-modulo-scheduled-loops @gol
--frounding-math -frtl-abstract-sequences -fsched2-use-superblocks @gol
+-frounding-math -fsched2-use-superblocks @gol
-fsched2-use-traces -fsched-spec-load -fsched-spec-load-dangerous @gol
-fsched-stalled-insns-dep[=@var{n}] -fsched-stalled-insns[=@var{n}] @gol
--fschedule-insns -fschedule-insns2 -fsection-anchors -fsee @gol
+-fsched-group-heuristic -fsched-critical-path-heuristic @gol
+-fsched-spec-insn-heuristic -fsched-reg-pressure-heuristic @gol
+-fsched-rank-heuristic -fsched-last-insn-heuristic @gol
+-fsched-dep-count-heuristic @gol
+-fschedule-insns -fschedule-insns2 -fsection-anchors @gol
-fselective-scheduling -fselective-scheduling2 @gol
-fsel-sched-pipelining -fsel-sched-pipelining-outer-loops @gol
-fsignaling-nans -fsingle-precision-constant -fsplit-ivs-in-unroller @gol
-fstrict-aliasing -fstrict-overflow -fthread-jumps -ftracer @gol
-ftree-builtin-call-dce -ftree-ccp -ftree-ch -ftree-copy-prop @gol
-ftree-copyrename -ftree-dce @gol
--ftree-dominator-opts -ftree-dse -ftree-fre -ftree-loop-im @gol
--ftree-loop-distribution @gol
+-ftree-dominator-opts -ftree-dse -ftree-forwprop -ftree-fre -ftree-loop-im @gol
+-ftree-phiprop -ftree-loop-distribution @gol
-ftree-loop-ivcanon -ftree-loop-linear -ftree-loop-optimize @gol
--ftree-parallelize-loops=@var{n} -ftree-pre -ftree-reassoc @gol
+-ftree-parallelize-loops=@var{n} -ftree-pre -ftree-pta -ftree-reassoc @gol
-ftree-sink -ftree-sra -ftree-switch-conversion @gol
-ftree-ter -ftree-vect-loop-version -ftree-vectorize -ftree-vrp @gol
-funit-at-a-time -funroll-all-loops -funroll-loops @gol
@xref{Link Options,,Options for Linking}.
@gccoptlist{@var{object-file-name} -l@var{library} @gol
-nostartfiles -nodefaultlibs -nostdlib -pie -rdynamic @gol
--s -static -static-libgcc -shared -shared-libgcc -symbolic @gol
+-s -static -static-libgcc -static-libstdc++ -shared @gol
+-shared-libgcc -symbolic @gol
-T @var{script} -Wl,@var{option} -Xlinker @var{option} @gol
-u @var{symbol}}
-msched-prolog -mno-sched-prolog @gol
-mlittle-endian -mbig-endian -mwords-little-endian @gol
-mfloat-abi=@var{name} -msoft-float -mhard-float -mfpe @gol
+-mfp16-format=@var{name}
-mthumb-interwork -mno-thumb-interwork @gol
-mcpu=@var{name} -march=@var{name} -mfpu=@var{name} @gol
-mstructure-size-boundary=@var{n} @gol
@emph{AVR Options}
@gccoptlist{-mmcu=@var{mcu} -msize -minit-stack=@var{n} -mno-interrupts @gol
--mcall-prologues -mno-tablejump -mtiny-stack -mint8}
+-mcall-prologues -mtiny-stack -mint8}
@emph{Blackfin Options}
@gccoptlist{-mcpu=@var{cpu}@r{[}-@var{sirevision}@r{]} @gol
-mmemory-latency=@var{time}}
@emph{DEC Alpha/VMS Options}
-@gccoptlist{-mvms-return-codes}
+@gccoptlist{-mvms-return-codes -mdebug-main=@var{prefix} -mmalloc64}
+
+@emph{FR30 Options}
+@gccoptlist{-msmall-model -mno-lsim}
@emph{FRV Options}
@gccoptlist{-mgpr-32 -mgpr-64 -mfpr-32 -mfpr-64 @gol
-mno-wide-multiply -mrtd -malign-double @gol
-mpreferred-stack-boundary=@var{num}
-mincoming-stack-boundary=@var{num}
--mcld -mcx16 -msahf -mrecip @gol
+-mcld -mcx16 -msahf -mmovbe -mcrc32 -mrecip @gol
-mmmx -msse -msse2 -msse3 -mssse3 -msse4.1 -msse4.2 -msse4 -mavx @gol
-maes -mpclmul @gol
-msse4a -m3dnow -mpopcnt -mabm -msse5 @gol
-m96bit-long-double -mregparm=@var{num} -msseregparm @gol
-mveclibabi=@var{type} -mpc32 -mpc64 -mpc80 -mstackrealign @gol
-momit-leaf-frame-pointer -mno-red-zone -mno-tls-direct-seg-refs @gol
--mcmodel=@var{code-model} @gol
+-mcmodel=@var{code-model} -mabi=@var{name} @gol
-m32 -m64 -mlarge-data-threshold=@var{num} @gol
-mfused-madd -mno-fused-madd -msse2avx}
@emph{IA-64 Options}
@gccoptlist{-mbig-endian -mlittle-endian -mgnu-as -mgnu-ld -mno-pic @gol
--mvolatile-asm-stop -mregister-names -mno-sdata @gol
--mconstant-gp -mauto-pic -minline-float-divide-min-latency @gol
+-mvolatile-asm-stop -mregister-names -msdata -mno-sdata @gol
+-mconstant-gp -mauto-pic -mfused-madd @gol
+-minline-float-divide-min-latency @gol
-minline-float-divide-max-throughput @gol
+-mno-inline-float-divide @gol
-minline-int-divide-min-latency @gol
-minline-int-divide-max-throughput @gol
+-mno-inline-int-divide @gol
-minline-sqrt-min-latency -minline-sqrt-max-throughput @gol
--mno-dwarf2-asm -mearly-stop-bits @gol
+-mno-inline-sqrt @gol
+-mdwarf2-asm -mearly-stop-bits @gol
-mfixed-range=@var{register-range} -mtls-size=@var{tls-size} @gol
--mtune=@var{cpu-type} -mt -pthread -milp32 -mlp64 @gol
--mno-sched-br-data-spec -msched-ar-data-spec -mno-sched-control-spec @gol
+-mtune=@var{cpu-type} -milp32 -mlp64 @gol
+-msched-br-data-spec -msched-ar-data-spec -msched-control-spec @gol
-msched-br-in-data-spec -msched-ar-in-data-spec -msched-in-control-spec @gol
--msched-ldc -mno-sched-control-ldc -mno-sched-spec-verbose @gol
--mno-sched-prefer-non-data-spec-insns @gol
--mno-sched-prefer-non-control-spec-insns @gol
--mno-sched-count-spec-in-critical-path}
+-msched-spec-ldc -msched-spec-control-ldc @gol
+-msched-prefer-non-data-spec-insns -msched-prefer-non-control-spec-insns @gol
+-msched-stop-bits-after-every-cycle -msched-count-spec-in-critical-path @gol
+-msel-sched-dont-check-control-spec -msched-fp-mem-deps-zero-cost @gol
+-msched-max-memory-insns-hard-limit -msched-max-memory-insns=@var{max-insns}}
@emph{M32R/D Options}
@gccoptlist{-m32r2 -m32rx -m32r @gol
-mno-callgraph-data -mslow-bytes -mno-slow-bytes -mno-lsim @gol
-mlittle-endian -mbig-endian -m210 -m340 -mstack-increment}
+@emph{MeP Options}
+@gccoptlist{-mabsdiff -mall-opts -maverage -mbased=@var{n} -mbitops @gol
+-mc=@var{n} -mclip -mconfig=@var{name} -mcop -mcop32 -mcop64 -mivc2 @gol
+-mdc -mdiv -meb -mel -mio-volatile -ml -mleadz -mm -mminmax @gol
+-mmult -mno-opts -mrepeat -ms -msatur -msdram -msim -msimnovec -mtf @gol
+-mtiny=@var{n}}
+
@emph{MIPS Options}
@gccoptlist{-EL -EB -march=@var{arch} -mtune=@var{arch} @gol
-mips1 -mips2 -mips3 -mips4 -mips32 -mips32r2 @gol
-mflush-func=@var{func} -mno-flush-func @gol
-mbranch-cost=@var{num} -mbranch-likely -mno-branch-likely @gol
-mfp-exceptions -mno-fp-exceptions @gol
--mvr4130-align -mno-vr4130-align}
+-mvr4130-align -mno-vr4130-align -msynci -mno-synci}
@emph{MMIX Options}
@gccoptlist{-mlibfuncs -mno-libfuncs -mepsilon -mno-epsilon -mabi=gnu @gol
-maltivec -mno-altivec @gol
-mpowerpc-gpopt -mno-powerpc-gpopt @gol
-mpowerpc-gfxopt -mno-powerpc-gfxopt @gol
--mmfcrf -mno-mfcrf -mpopcntb -mno-popcntb -mfprnd -mno-fprnd @gol
+-mmfcrf -mno-mfcrf -mpopcntb -mno-popcntb -mpopcntd -mno-popcntd @gol
+-mfprnd -mno-fprnd @gol
-mcmpb -mno-cmpb -mmfpgpr -mno-mfpgpr -mhard-dfp -mno-hard-dfp @gol
-mnew-mnemonics -mold-mnemonics @gol
-mfull-toc -mminimal-toc -mno-fp-in-toc -mno-sum-in-toc @gol
-mstrict-align -mno-strict-align -mrelocatable @gol
-mno-relocatable -mrelocatable-lib -mno-relocatable-lib @gol
-mtoc -mno-toc -mlittle -mlittle-endian -mbig -mbig-endian @gol
--mdynamic-no-pic -maltivec -mswdiv @gol
+-mdynamic-no-pic -maltivec -mswdiv @gol
-mprioritize-restricted-insns=@var{priority} @gol
-msched-costly-dep=@var{dependence_type} @gol
-minsert-sched-nops=@var{scheme} @gol
-mscore5 -mscore5u -mscore7 -mscore7d}
@emph{SH Options}
-@gccoptlist{-m1 -m2 -m2e -m3 -m3e @gol
+@gccoptlist{-m1 -m2 -m2e @gol
+-m2a-nofpu -m2a-single-only -m2a-single -m2a @gol
+-m3 -m3e @gol
-m4-nofpu -m4-single-only -m4-single -m4 @gol
-m4a-nofpu -m4a-single-only -m4a-single -m4a -m4al @gol
-m5-64media -m5-64media-nofpu @gol
-m5-32media -m5-32media-nofpu @gol
-m5-compact -m5-compact-nofpu @gol
-mb -ml -mdalign -mrelax @gol
--mbigtable -mfmovd -mhitachi -mrenesas -mno-renesas -mnomacsave @gol
+-mbigtable -mfmovd -mhitachi -mrenesas -mno-renesas -mnomacsave @gol
-mieee -mbitops -misize -minline-ic_invalidate -mpadstruct -mspace @gol
-mprefergot -musermode -multcost=@var{number} -mdiv=@var{strategy} @gol
-mdivsi3_libfunc=@var{name} -mfixed-range=@var{register-range} @gol
@emph{x86-64 Options}
See i386 and x86-64 Options.
+@emph{i386 and x86-64 Windows Options}
+@gccoptlist{-mconsole -mcygwin -mno-cygwin -mdll
+-mnop-fun-dllimport -mthread -municode -mwin32 -mwindows}
+
@emph{Xstormy16 Options}
@gccoptlist{-msim}
line options for each tool. For some targets extra target-specific
information may also be printed.
-@item --help=@var{class}@r{[},@var{qualifier}@r{]}
+@item --help=@{@var{class}@r{|[}^@r{]}@var{qualifier}@}@r{[},@dots{}@r{]}
Print (on the standard output) a description of the command line
-options understood by the compiler that fit into a specific class.
-The class can be one of @samp{optimizers}, @samp{warnings}, @samp{target},
-@samp{params}, or @var{language}:
+options understood by the compiler that fit into all specified classes
+and qualifiers. These are the supported classes:
@table @asis
@item @samp{optimizers}
option.
@item @var{language}
-This will display the options supported for @var{language}, where
-@var{language} is the name of one of the languages supported in this
+This will display the options supported for @var{language}, where
+@var{language} is the name of one of the languages supported in this
version of GCC.
@item @samp{common}
This will display the options that are common to all languages.
@end table
-It is possible to further refine the output of the @option{--help=}
-option by adding a comma separated list of qualifiers after the
-class. These can be any from the following list:
+These are the supported qualifiers:
@table @asis
@item @samp{undocumented}
@end smallexample
The sense of a qualifier can be inverted by prefixing it with the
-@var{^} character, so for example to display all binary warning
+@samp{^} character, so for example to display all binary warning
options (i.e., ones that are either on or off and that do not take an
argument), which have a description the following can be used:
--help=warnings,^joined,^undocumented
@end smallexample
-A class can also be used as a qualifier, although this usually
+The argument to @option{--help=} should not consist solely of inverted
+qualifiers.
+
+Combining several classes is possible, although this usually
restricts the output by so much that there is nothing to display. One
case where it does work however is when one of the classes is
@var{target}. So for example to display all the target-specific
are enabled at @option{-O2} by using:
@smallexample
--O2 --help=optimizers
+-Q -O2 --help=optimizers
@end smallexample
Alternatively you can discover which binary optimizations are enabled
diff /tmp/O2-opts /tmp/O3-opts | grep enabled
@end smallexample
+@item -no-canonical-prefixes
+@opindex no-canonical-prefixes
+Do not expand any symbolic links, resolve references to @samp{/../}
+or @samp{/./}, or make the path absolute when generating a relative
+prefix.
+
@item --version
@opindex version
Display the version number and copyrights of the invoked GCC@.
This will invoke all subprograms of gcc under "gdb --args",
thus cc1 invocation will be "gdb --args cc1 ...".
+@item -fplugin=@var{name}.so
+Load the plugin code in file @var{name}.so, assumed to be a
+shared object to be dlopen'd by the compiler. The base name of
+the shared object file is used to identify the plugin for the
+purposes of argument parsing (See
+@option{-fplugin-arg-@var{name}-@var{key}=@var{value}} below).
+Each plugin should define the callback functions specified in the
+Plugins API.
+
+@item -fplugin-arg-@var{name}-@var{key}=@var{value}
+Define an argument called @var{key} with a value of @var{value}
+for the plugin called @var{name}.
+
@include @value{srcdir}/../libiberty/at-file.texi
@end table
@opindex std
Determine the language standard. @xref{Standards,,Language Standards
Supported by GCC}, for details of these standard versions. This option
-is currently only supported when compiling C or C++.
+is currently only supported when compiling C or C++.
The compiler can accept several base standards, such as @samp{c89} or
@samp{c++98}, and GNU dialects of those standards, such as
Enable handling of OpenMP directives @code{#pragma omp} in C/C++ and
@code{!$omp} in Fortran. When @option{-fopenmp} is specified, the
compiler generates parallel code according to the OpenMP Application
-Program Interface v2.5 @w{@uref{http://www.openmp.org/}}. This option
+Program Interface v3.0 @w{@uref{http://www.openmp.org/}}. This option
implies @option{-pthread}, and thus is only supported on targets that
have support for @option{-pthread}.
warnings. Thus, using @option{-fpermissive} will allow some
nonconforming code to compile.
+@item -fno-pretty-templates
+@opindex fno-pretty-templates
+When an error message refers to a specialization of a function
+template, the compiler will normally print the signature of the
+template followed by the template arguments and any typedefs or
+typenames in the signature (e.g. @code{void f(T) [with T = int]}
+rather than @code{void f(int)}) so that it's clear which template is
+involved. When an error message refers to a specialization of a class
+template, the compiler will omit any template arguments which match
+the default template arguments for that template. If either of these
+behaviors make it harder to understand the error message rather than
+easier, using @option{-fno-pretty-templates} will disable them.
+
@item -frepo
@opindex frepo
Enable automatic template instantiation at link time. This option also
functions will have linkage like inline functions; they just won't be
inlined by default.
-@item -Wabi @r{(C++ and Objective-C++ only)}
+@item -Wabi @r{(C, Objective-C, C++ and Objective-C++ only)}
@opindex Wabi
@opindex Wno-abi
Warn when G++ generates code that is probably not compatible with the
@end itemize
+It also warns psABI related changes. The known psABI changes at this
+point include:
+
+@itemize @bullet
+
+@item
+For SYSV/x86-64, when passing union with long double, it is changed to
+pass in memory as specified in psABI. For example:
+
+@smallexample
+union U @{
+ long double ld;
+ int i;
+@};
+@end smallexample
+
+@noindent
+@code{union U} will always be passed in memory.
+
+@end itemize
+
@item -Wctor-dtor-privacy @r{(C++ and Objective-C++ only)}
@opindex Wctor-dtor-privacy
@opindex Wno-ctor-dtor-privacy
-Warray-bounds @r{(only with} @option{-O2}@r{)} @gol
-Wc++0x-compat @gol
-Wchar-subscripts @gol
+-Wenum-compare @r{(in C/Objc; this is on by default in C++)} @gol
-Wimplicit-int @gol
-Wimplicit-function-declaration @gol
-Wcomment @gol
A pointer is compared against integer zero with @samp{<}, @samp{<=},
@samp{>}, or @samp{>=}.
-@item
+@item
(C++ only) An enumerator and a non-enumerator both appear in a
conditional expression.
-@item
+@item
(C++ only) Ambiguous virtual bases.
-@item
+@item
(C++ only) Subscripting an array which has been declared @samp{register}.
-@item
+@item
(C++ only) Taking the address of a variable which has been declared
@samp{register}.
-@item
+@item
(C++ only) A base class is not initialized in a derived class' copy
constructor.
@option{-Wnonnull} is included in @option{-Wall} and @option{-Wformat}. It
can be disabled with the @option{-Wno-nonnull} option.
+@item -Wjump-misses-init @r{(C, Objective-C only)}
+@opindex Wjump-misses-init
+@opindex Wno-jump-misses-init
+Warn if a @code{goto} statement or a @code{switch} statement jumps
+forward across the initialization of a variable, or jumps backward to a
+label after the variable has been initialized. This only warns about
+variables which are initialized when they are declared. This warning is
+only supported for C and Objective C; in C++ this sort of branch is an
+error in any case.
+
+@option{-Wjump-misses-init} is included in @option{-Wall} and
+@option{-Wc++-compat}. It can be disabled with the
+@option{-Wno-jump-misses-init} option.
+
@item -Winit-self @r{(C, C++, Objective-C and Objective-C++ only)}
@opindex Winit-self
@opindex Wno-init-self
to @code{int}. Also warn about any @code{return} statement with no
return-value in a function whose return-type is not @code{void}
(falling off the end of the function body is considered returning
-without a value), and about a @code{return} statement with a
+without a value), and about a @code{return} statement with an
expression in a function whose return-type is @code{void}.
For C++, a function without return type always produces a diagnostic
and lacks a @code{case} for one or more of the named codes of that
enumeration. (The presence of a @code{default} label prevents this
warning.) @code{case} labels outside the enumeration range also
-provoke warnings when this option is used.
+provoke warnings when this option is used (even if there is a
+@code{default} label).
This warning is enabled by @option{-Wall}.
@item -Wswitch-default
Warn whenever a @code{switch} statement has an index of enumerated type
and lacks a @code{case} for one or more of the named codes of that
enumeration. @code{case} labels outside the enumeration range also
-provoke warnings when this option is used.
+provoke warnings when this option is used. The only difference
+between @option{-Wswitch} and this option is that this option gives a
+warning about an omitted enumeration code even if there is a
+@code{default} label.
-@item -Wsync-nand
+@item -Wsync-nand @r{(C and C++ only)}
@opindex Wsync-nand
@opindex Wno-sync-nand
Warn when @code{__sync_fetch_and_nand} and @code{__sync_nand_and_fetch}
To suppress this warning use the @samp{unused} attribute
(@pxref{Variable Attributes}).
+@item -Wno-unused-result
+@opindex Wunused-result
+@opindex Wno-unused-result
+Do not warn if a caller of a function marked with attribute
+@code{warn_unused_result} (@pxref{Variable Attributes}) does not use
+its return value. The default is @option{-Wunused-result}.
+
@item -Wunused-variable
@opindex Wunused-variable
@opindex Wno-unused-variable
Level 1: Most aggressive, quick, least accurate.
Possibly useful when higher levels
-do not warn but -fstrict-aliasing still breaks the code, as it has very few
+do not warn but -fstrict-aliasing still breaks the code, as it has very few
false negatives. However, it has many false positives.
-Warns for all pointer conversions between possibly incompatible types,
+Warns for all pointer conversions between possibly incompatible types,
even if never dereferenced. Runs in the frontend only.
Level 2: Aggressive, quick, not too precise.
Unlike level 1, it only warns when an address is taken. Warns about
incomplete types. Runs in the frontend only.
-Level 3 (default for @option{-Wstrict-aliasing}):
-Should have very few false positives and few false
+Level 3 (default for @option{-Wstrict-aliasing}):
+Should have very few false positives and few false
negatives. Slightly slower than levels 1 or 2 when optimization is enabled.
Takes care of the common punn+dereference pattern in the frontend:
@code{*(int*)&some_float}.
-If optimization is enabled, it also runs in the backend, where it deals
+If optimization is enabled, it also runs in the backend, where it deals
with multiple statement cases using flow-sensitive points-to information.
Only warns when the converted pointer is dereferenced.
Does not warn about incomplete types.
@option{-funsafe-loop-optimizations} warn if the compiler made
such assumptions.
-@item -Wno-pedantic-ms-format
+@item -Wno-pedantic-ms-format @r{(MinGW targets only)}
@opindex Wno-pedantic-ms-format
@opindex Wpedantic-ms-format
Disables the warnings about non-ISO @code{printf} / @code{scanf} format
the target type. For example, warn if a @code{const char *} is cast
to an ordinary @code{char *}.
+Also warn when making a cast which introduces a type qualifier in an
+unsafe way. For example, casting @code{char **} to @code{const char **}
+is unsafe, as in this example:
+
+@smallexample
+ /* p is char ** value. */
+ const char **q = (const char **) p;
+ /* Assignment of readonly string to const char * is OK. */
+ *q = "string";
+ /* Now char** pointer points to read-only memory. */
+ **p = 'b';
+@end smallexample
+
@item -Wcast-align
@opindex Wcast-align
@opindex Wno-cast-align
Warn if an empty body occurs in an @samp{if}, @samp{else} or @samp{do
while} statement. This warning is also enabled by @option{-Wextra}.
-@item -Wenum-compare @r{(C++ and Objective-C++ only)}
+@item -Wenum-compare
@opindex Wenum-compare
@opindex Wno-enum-compare
-Warn about a comparison between values of different enum types. This
-warning is enabled by default.
+Warn about a comparison between values of different enum types. In C++
+this warning is enabled by default. In C this warning is enabled by
+@option{-Wall}.
@item -Wsign-compare
@opindex Wsign-compare
@item -Wlong-long
@opindex Wlong-long
@opindex Wno-long-long
-Warn if @samp{long long} type is used. This is default. To inhibit
-the warning messages, use @option{-Wno-long-long}. Flags
-@option{-Wlong-long} and @option{-Wno-long-long} are taken into account
-only when @option{-pedantic} flag is used.
+Warn if @samp{long long} type is used. This is enabled by either
+@option{-pedantic} or @option{-Wtraditional} in ISO C90 and C++98
+modes. To inhibit the warning messages, use @option{-Wno-long-long}.
@item -Wvariadic-macros
@opindex Wvariadic-macros
This option is implied by @option{-pedantic}, and can be disabled with
@option{-Wno-overlength-strings}.
-@item -Wdisallowed-function-list=@var{sym},@var{sym},@dots{}
-@opindex Wdisallowed-function-list
+@item -Wunsuffixed-float-constants
+@opindex Wunsuffixed-float-constants
-If any of @var{sym} is called, GCC will issue a warning. This can be useful
-in enforcing coding conventions that ban calls to certain functions, for
-example, @code{alloca}, @code{malloc}, etc.
+GCC will issue a warning for any floating constant that does not have
+a suffix. When used together with @option{-Wsystem-headers} it will
+warn about such constants in system header files. This can be useful
+when preparing code to use with the @code{FLOAT_CONST_DECIMAL64} pragma
+from the decimal floating-point extension to C99.
@end table
@node Debugging Options
refuse to read the program, and may cause assemblers other than the GNU
assembler (GAS) to fail with an error.
-@item -gdwarf-2
-@opindex gdwarf-2
-Produce debugging information in DWARF version 2 format (if that is
-supported). This is the format used by DBX on IRIX 6. With this
-option, GCC uses features of DWARF version 3 when they are useful;
-version 3 is upward compatible with version 2, but may still cause
-problems for older debuggers.
+@item -gdwarf-@var{version}
+@opindex gdwarf-@var{version}
+Produce debugging information in DWARF format (if that is
+supported). This is the format used by DBX on IRIX 6. The value
+of @var{version} may be either 2 or 3; the default version is 2.
+
+Note that with DWARF version 2 some ports require, and will always
+use, some non-conflicting DWARF 3 extensions in the unwind tables.
@item -gvms
@opindex gvms
different from version 2), and it would have been too confusing. That
debug format is long obsolete, but the option cannot be changed now.
Instead use an additional @option{-g@var{level}} option to change the
-debug level for DWARF2.
+debug level for DWARF.
+
+@item -gtoggle
+@opindex gtoggle
+Turn off generation of debug info, if leaving out this option would have
+generated it, or turn it on at level 2 otherwise. The position of this
+argument in the command line does not matter, it takes effect after all
+other options are processed, and it does so only once, no matter how
+many times it is given. This is mainly intended to be used with
+@option{-fcompare-debug}.
+
+@item -fdump-final-insns=@var{file}
+@opindex fdump-final-insns=
+Dump the final internal representation (RTL) to @var{file}.
+
+@item -fcompare-debug@r{[}=@var{opts}@r{]}
+@opindex fcompare-debug
+@opindex fno-compare-debug
+If no error occurs during compilation, run the compiler a second time,
+adding @var{opts} and @option{-fcompare-debug-second} to the arguments
+passed to the second compilation. Dump the final internal
+representation in both compilations, and print an error if they differ.
+
+If the equal sign is omitted, the default @option{-gtoggle} is used.
+
+The environment variable @env{GCC_COMPARE_DEBUG}, if defined, non-empty
+and nonzero, implicitly enables @option{-fcompare-debug}. If
+@env{GCC_COMPARE_DEBUG} is defined to a string starting with a dash,
+then it is used for @var{opts}, otherwise the default @option{-gtoggle}
+is used.
+
+@option{-fcompare-debug=}, with the equal sign but without @var{opts},
+is equivalent to @option{-fno-compare-debug}, which disables the dumping
+of the final representation and the second compilation, preventing even
+@env{GCC_COMPARE_DEBUG} from taking effect.
+
+To verify full coverage during @option{-fcompare-debug} testing, set
+@env{GCC_COMPARE_DEBUG} to say @samp{-fcompare-debug-not-overridden},
+which GCC will reject as an invalid option in any actual compilation
+(rather than preprocessing, assembly or linking). To get just a
+warning, setting @env{GCC_COMPARE_DEBUG} to @samp{-w%n-fcompare-debug
+not overridden} will do.
+
+@item -fcompare-debug-second
+@opindex fcompare-debug-second
+This option is implicitly passed to the compiler for the second
+compilation requested by @option{-fcompare-debug}, along with options to
+silence warnings, and omitting other options that would cause
+side-effect compiler outputs to files or to the standard output. Dump
+files and preserved temporary files are renamed so as to contain the
+@code{.gk} additional extension during the second compilation, to avoid
+overwriting those generated by the first.
+
+When this option is passed to the compiler driver, it causes the
+@emph{first} compilation to be skipped, which makes it useful for little
+other than debugging the compiler proper.
@item -feliminate-dwarf2-dups
@opindex feliminate-dwarf2-dups
@item -fno-merge-debug-strings
@opindex fmerge-debug-strings
@opindex fno-merge-debug-strings
-Direct the linker to merge together strings which are identical in
-different object files. This is not supported by all assemblers or
-linker. This decreases the size of the debug information in the
-output file at the cost of increasing link processing time. This is
-on by default.
+Direct the linker to not merge together strings in the debugging
+information which are identical in different object files. Merging is
+not supported by all assemblers or linkers. Merging decreases the size
+of the debug information in the output file at the cost of increasing
+link processing time. Merging is enabled by default.
@item -fdebug-prefix-map=@var{old}=@var{new}
@opindex fdebug-prefix-map
@item -fdbg-cnt=@var{counter-value-list}
@opindex fdbg-cnt
-Set the internal debug counter upperbound. @var{counter-value-list}
+Set the internal debug counter upperbound. @var{counter-value-list}
is a comma-separated list of @var{name}:@var{value} pairs
which sets the upperbound of each debug counter @var{name} to @var{value}.
All debug counters have the initial upperbound of @var{UINT_MAX},
@itemx -fdump-rtl-@var{pass}
@opindex d
Says to make debugging dumps during compilation at times specified by
-@var{letters}. This is used for debugging the RTL-based passes of the
-compiler. The file names for most of the dumps are made by appending a
-pass number and a word to the @var{dumpname}. @var{dumpname} is generated
-from the name of the output file, if explicitly specified and it is not
-an executable, otherwise it is the basename of the source file. These
-switches may have different effects when @option{-E} is used for
-preprocessing.
+@var{letters}. This is used for debugging the RTL-based passes of the
+compiler. The file names for most of the dumps are made by appending
+a pass number and a word to the @var{dumpname}, and the files are
+created in the directory of the output file. @var{dumpname} is
+generated from the name of the output file, if explicitly specified
+and it is not an executable, otherwise it is the basename of the
+source file. These switches may have different effects when
+@option{-E} is used for preprocessing.
Debug dumps can be enabled with a @option{-fdump-rtl} switch or some
@option{-d} option @var{letters}. Here are the possible
@item -fdump-rtl-compgotos
@opindex fdump-rtl-compgotos
-Dump after dumplicating the computed gotos.
+Dump after duplicating the computed gotos.
@item -fdump-rtl-ce1
@itemx -fdump-rtl-ce2
@opindex fdump-rtl-ce3
@option{-fdump-rtl-ce1}, @option{-fdump-rtl-ce2}, and
@option{-fdump-rtl-ce3} enable dumping after the three
-if conversion passes.
+if conversion passes.
@itemx -fdump-rtl-cprop_hardreg
@opindex fdump-rtl-cprop_hardreg
@item -fdump-rtl-seqabstr
@opindex fdump-rtl-seqabstr
-Dump after common sequence discovery.
+Dump after common sequence discovery.
@item -fdump-rtl-shorten
@opindex fdump-rtl-shorten
invocations with different options, in particular with and without
@option{-g}.
+@item -fdump-unnumbered-links
+@opindex fdump-unnumbered-links
+When doing debugging dumps (see @option{-d} option above), suppress
+instruction numbers for the links to the previous and next instructions
+in a sequence.
+
@item -fdump-translation-unit @r{(C++ only)}
@itemx -fdump-translation-unit-@var{options} @r{(C++ only)}
@opindex fdump-translation-unit
Dump a representation of the tree structure for the entire translation
unit to a file. The file name is made by appending @file{.tu} to the
-source file name. If the @samp{-@var{options}} form is used, @var{options}
+source file name, and the file is created in the same directory as the
+output file. If the @samp{-@var{options}} form is used, @var{options}
controls the details of the dump as described for the
@option{-fdump-tree} options.
@itemx -fdump-class-hierarchy-@var{options} @r{(C++ only)}
@opindex fdump-class-hierarchy
Dump a representation of each class's hierarchy and virtual function
-table layout to a file. The file name is made by appending @file{.class}
-to the source file name. If the @samp{-@var{options}} form is used,
-@var{options} controls the details of the dump as described for the
-@option{-fdump-tree} options.
+table layout to a file. The file name is made by appending
+@file{.class} to the source file name, and the file is created in the
+same directory as the output file. If the @samp{-@var{options}} form
+is used, @var{options} controls the details of the dump as described
+for the @option{-fdump-tree} options.
@item -fdump-ipa-@var{switch}
@opindex fdump-ipa
Control the dumping at various stages of inter-procedural analysis
-language tree to a file. The file name is generated by appending a switch
-specific suffix to the source file name. The following dumps are possible:
+language tree to a file. The file name is generated by appending a
+switch specific suffix to the source file name, and the file is created
+in the same directory as the output file. The following dumps are
+possible:
@table @samp
@item all
@end table
@item -fdump-statistics-@var{option}
-@opindex -fdump-statistics
+@opindex fdump-statistics
Enable and control dumping of pass statistics in a separate file. The
-file name is generated by appending a suffix ending in @samp{.statistics}
-to the source file name. If the @samp{-@var{option}} form is used,
-@samp{-stats} will cause counters to be summed over the whole compilation unit
-while @samp{-details} will dump every event as the passes generate them.
-The default with no option is to sum counters for each function compiled.
+file name is generated by appending a suffix ending in
+@samp{.statistics} to the source file name, and the file is created in
+the same directory as the output file. If the @samp{-@var{option}}
+form is used, @samp{-stats} will cause counters to be summed over the
+whole compilation unit while @samp{-details} will dump every event as
+the passes generate them. The default with no option is to sum
+counters for each function compiled.
@item -fdump-tree-@var{switch}
@itemx -fdump-tree-@var{switch}-@var{options}
@opindex fdump-tree
Control the dumping at various stages of processing the intermediate
-language tree to a file. The file name is generated by appending a switch
-specific suffix to the source file name. If the @samp{-@var{options}}
-form is used, @var{options} is a list of @samp{-} separated options that
-control the details of the dump. Not all options are applicable to all
-dumps, those which are not meaningful will be ignored. The following
-options are available
+language tree to a file. The file name is generated by appending a
+switch specific suffix to the source file name, and the file is
+created in the same directory as the output file. If the
+@samp{-@var{options}} form is used, @var{options} is a list of
+@samp{-} separated options that control the details of the dump. Not
+all options are applicable to all dumps, those which are not
+meaningful will be ignored. The following options are available
@table @samp
@item 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 environment.
+@item asmname
+If @code{DECL_ASSEMBLER_NAME} has been set for a given decl, use that
+in the dump instead of @code{DECL_NAME}. Its primary use is ease of
+use working backward from mangled names in the assembly file.
@item 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
Enable showing the unique ID (@code{DECL_UID}) for each variable.
@item verbose
Enable showing the tree dump for each statement.
+@item eh
+Enable showing the EH region number holding each statement.
@item all
Turn on all options, except @option{raw}, @option{slim}, @option{verbose}
and @option{lineno}.
@table @samp
@item original
+@opindex fdump-tree-original
Dump before any tree based optimization, to @file{@var{file}.original}.
@item optimized
+@opindex fdump-tree-optimized
Dump after all tree based optimization, to @file{@var{file}.optimized}.
@item gimple
that @option{-fdump-tree-vect-details} uses.
@item -frandom-seed=@var{string}
-@opindex frandom-string
+@opindex frandom-seed
This option provides a seed that GCC uses when it would otherwise use
random numbers. It is used to generate certain symbol names
that have to be different in every compiled file. It is also used to
dependence info.
@item -save-temps
+@itemx -save-temps=cwd
@opindex save-temps
Store the usual ``temporary'' intermediate files permanently; place them
in the current directory and name them based on the source file. Thus,
The corresponding intermediate file may be obtained by renaming the
source file before using @option{-save-temps}.
-@item -time
+If you invoke GCC in parallel, compiling several different source
+files that share a common base name in different subdirectories or the
+same source file compiled for multiple output destinations, it is
+likely that the different parallel compilers will interfere with each
+other, and overwrite the temporary files. For instance:
+
+@smallexample
+gcc -save-temps -o outdir1/foo.o indir1/foo.c&
+gcc -save-temps -o outdir2/foo.o indir2/foo.c&
+@end smallexample
+
+may result in @file{foo.i} and @file{foo.o} being written to
+simultaneously by both compilers.
+
+@item -save-temps=obj
+@opindex save-temps=obj
+Store the usual ``temporary'' intermediate files permanently. If the
+@option{-o} option is used, the temporary files are based on the
+object file. If the @option{-o} option is not used, the
+@option{-save-temps=obj} switch behaves like @option{-save-temps}.
+
+For example:
+
+@smallexample
+gcc -save-temps=obj -c foo.c
+gcc -save-temps=obj -c bar.c -o dir/xbar.o
+gcc -save-temps=obj foobar.c -o dir2/yfoobar
+@end smallexample
+
+would create @file{foo.i}, @file{foo.s}, @file{dir/xbar.i},
+@file{dir/xbar.s}, @file{dir2/yfoobar.i}, @file{dir2/yfoobar.s}, and
+@file{dir2/yfoobar.o}.
+
+@item -time@r{[}=@var{file}@r{]}
@opindex 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:
+(plus the linker if linking is done).
+
+Without the specification of an output file, the output looks like this:
@smallexample
# cc1 0.12 0.01
time spent executing operating system routines on behalf of the program.
Both numbers are in seconds.
+With the specification of an output file, the output is appended to the
+named file, and it looks like this:
+
+@smallexample
+0.12 0.01 cc1 @var{options}
+0.00 0.01 as @var{options}
+@end smallexample
+
+The ``user time'' and the ``system time'' are moved before the program
+name, and the options passed to the program are displayed, so that one
+can later tell what file was being compiled, and with which options.
+
@item -fvar-tracking
@opindex fvar-tracking
Run variable tracking pass. It computes where variables are stored at each
each of them.
Not all optimizations are controlled directly by a flag. Only
-optimizations that have a flag are listed.
+optimizations that have a flag are listed in this section.
+
+Depending on the target and how GCC was configured, a slightly different
+set of optimizations may be enabled at each @option{-O} level than
+those listed here. You can invoke GCC with @samp{-Q --help=optimizers}
+to find out the exact set of optimizations that are enabled at each level.
+@xref{Overall Options}, for examples.
@table @gcctabopt
@item -O
-ftree-dce @gol
-ftree-dominator-opts @gol
-ftree-dse @gol
+-ftree-forwprop @gol
-ftree-fre @gol
+-ftree-phiprop @gol
-ftree-sra @gol
+-ftree-pta @gol
-ftree-ter @gol
-funit-at-a-time}
is active, two passes are performed and the second is scheduled after
loop unrolling.
-This option is enabled by default at optimization levels @option{-O2},
-@option{-O3}, @option{-Os}.
+This option is enabled by default at optimization levels @option{-O},
+@option{-O2}, @option{-O3}, @option{-Os}.
@item -fomit-frame-pointer
@opindex fomit-frame-pointer
@item -fdelete-null-pointer-checks
@opindex 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
-@option{-fno-delete-null-pointer-checks} to disable this optimization
+Assume that programs cannot safely dereference null pointers, and that
+no code or data element resides there. This enables simple constant
+folding optimizations at all optimization levels. In addition, other
+optimization passes in GCC use this flag to control global dataflow
+analyses that eliminate useless checks for null pointers; these assume
+that if a pointer is checked after it has already been dereferenced,
+it cannot be null.
+
+Note however that in some environments this assumption is not true.
+Use @option{-fno-delete-null-pointer-checks} to disable this optimization
for programs which depend on that behavior.
-Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}.
+Some targets, especially embedded ones, disable this option at all levels.
+Otherwise it is enabled at all levels: @option{-O0}, @option{-O1},
+@option{-O2}, @option{-O3}, @option{-Os}. Passes that use the information
+are enabled independently at different optimization levels.
@item -fexpensive-optimizations
@opindex fexpensive-optimizations
Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}.
-@item -fira
-@opindex fira
-Use the integrated register allocator (@acronym{IRA}) for register
-allocation. It is a default if @acronym{IRA} has been ported for the
-target.
-
@item -fira-algorithm=@var{algorithm}
Use specified coloring algorithm for the integrated register
allocator. The @var{algorithm} argument should be @code{priority} or
This only makes sense when scheduling after register allocation, i.e.@: with
@option{-fschedule-insns2} or at @option{-O2} or higher.
+@item -fsched-group-heuristic
+@opindex fsched-group-heuristic
+Enable the group heuristic in the scheduler. This heuristic favors
+the instruction that belongs to a schedule group. This is enabled
+by default when scheduling is enabled, i.e.@: with @option{-fschedule-insns}
+or @option{-fschedule-insns2} or at @option{-O2} or higher.
+
+@item -fsched-critical-path-heuristic
+@opindex fsched-critical-path-heuristic
+Enable the critical-path heuristic in the scheduler. This heuristic favors
+instructions on the critical path. This is enabled by default when
+scheduling is enabled, i.e.@: with @option{-fschedule-insns}
+or @option{-fschedule-insns2} or at @option{-O2} or higher.
+
+@item -fsched-spec-insn-heuristic
+@opindex fsched-spec-insn-heuristic
+Enable the speculative instruction heuristic in the scheduler. This
+heuristic favors speculative instructions with greater dependency weakness.
+This is enabled by default when scheduling is enabled, i.e.@:
+with @option{-fschedule-insns} or @option{-fschedule-insns2}
+or at @option{-O2} or higher.
+
+@item -fsched-reg-pressure-heuristic
+@opindex fsched-reg-pressure-heuristic
+Enable the register pressure heuristic in the scheduler. This heuristic
+favors the instruction with smaller contribution to register pressure.
+This only makes sense when scheduling before register allocation, i.e.@:
+with @option{-fschedule-insns} or at @option{-O2} or higher.
+
+@item -fsched-rank-heuristic
+@opindex fsched-rank-heuristic
+Enable the rank heuristic in the scheduler. This heuristic favors
+the instruction belonging to a basic block with greater size or frequency.
+This is enabled by default when scheduling is enabled, i.e.@:
+with @option{-fschedule-insns} or @option{-fschedule-insns2} or
+at @option{-O2} or higher.
+
+@item -fsched-last-insn-heuristic
+@opindex fsched-last-insn-heuristic
+Enable the last-instruction heuristic in the scheduler. This heuristic
+favors the instruction that is less dependent on the last instruction
+scheduled. This is enabled by default when scheduling is enabled,
+i.e.@: with @option{-fschedule-insns} or @option{-fschedule-insns2} or
+at @option{-O2} or higher.
+
+@item -fsched-dep-count-heuristic
+@opindex fsched-dep-count-heuristic
+Enable the dependent-count heuristic in the scheduler. This heuristic
+favors the instruction that has more instructions depending on it.
+This is enabled by default when scheduling is enabled, i.e.@:
+with @option{-fschedule-insns} or @option{-fschedule-insns2} or
+at @option{-O2} or higher.
+
@item -fsched2-use-traces
@opindex fsched2-use-traces
Use @option{-fsched2-use-superblocks} algorithm when scheduling after register
sense when scheduling after register allocation, i.e.@: with
@option{-fschedule-insns2} or at @option{-O2} or higher.
-@item -fsee
-@opindex fsee
-Eliminate redundant sign extension instructions and move the non-redundant
-ones to optimal placement using lazy code motion (LCM).
-
@item -freschedule-modulo-scheduled-loops
@opindex freschedule-modulo-scheduled-loops
The modulo scheduling comes before the traditional scheduling, if a loop
@item -fsel-sched-pipelining
@opindex fsel-sched-pipelining
-Enable software pipelining of innermost loops during selective scheduling.
-This option has no effect until one of @option{-fselective-scheduling} or
+Enable software pipelining of innermost loops during selective scheduling.
+This option has no effect until one of @option{-fselective-scheduling} or
@option{-fselective-scheduling2} is turned on.
@item -fsel-sched-pipelining-outer-loops
Perform partial redundancy elimination (PRE) on trees. This flag is
enabled by default at @option{-O2} and @option{-O3}.
+@item -ftree-forwprop
+@opindex ftree-forwprop
+Perform forward propagation on trees. This flag is enabled by default
+at @option{-O} and higher.
+
@item -ftree-fre
@opindex ftree-fre
Perform full redundancy elimination (FRE) on trees. The difference
This analysis is faster than PRE, though it exposes fewer redundancies.
This flag is enabled by default at @option{-O} and higher.
+@item -ftree-phiprop
+@opindex ftree-phiprop
+Perform hoisting of loads from conditional pointers on trees. This
+pass is enabled by default at @option{-O} and higher.
+
@item -ftree-copy-prop
@opindex ftree-copy-prop
Perform copy propagation on trees. This pass eliminates unnecessary
@item -fipa-struct-reorg
@opindex fipa-struct-reorg
-Perform structure reorganization optimization, that change C-like structures
-layout in order to better utilize spatial locality. This transformation is
-affective for programs containing arrays of structures. Available in two
+Perform structure reorganization optimization, that change C-like structures
+layout in order to better utilize spatial locality. This transformation is
+affective for programs containing arrays of structures. Available in two
compilation modes: profile-based (enabled with @option{-fprofile-generate})
or static (which uses built-in heuristics). Require @option{-fipa-type-escape}
to provide the safety of this transformation. It works only in whole program
@opindex fipa-cp
Perform interprocedural constant propagation.
This optimization analyzes the program to determine when values passed
-to functions are constants and then optimizes accordingly.
+to functions are constants and then optimizes accordingly.
This optimization can substantially increase performance
if the application has constants passed to functions.
This flag is enabled by default at @option{-O2}, @option{-Os} and @option{-O3}.
@item -fipa-matrix-reorg
@opindex fipa-matrix-reorg
Perform matrix flattening and transposing.
-Matrix flattening tries to replace a m-dimensional matrix
-with its equivalent n-dimensional matrix, where n < m.
+Matrix flattening tries to replace an @math{m}-dimensional matrix
+with its equivalent @math{n}-dimensional matrix, where @math{n < m}.
This reduces the level of indirection needed for accessing the elements
of the matrix. The second optimization is matrix transposing that
-attemps to change the order of the matrix's dimensions in order to
+attempts to change the order of the matrix's dimensions in order to
improve cache locality.
-Both optimizations need the @option{-fwhole-program} flag.
+Both optimizations need the @option{-fwhole-program} flag.
Transposing is enabled only if profiling information is available.
-
@item -ftree-sink
@opindex ftree-sink
Perform forward store motion on trees. This flag is
@item -ftree-builtin-call-dce
@opindex ftree-builtin-call-dce
-Perform conditional dead code elimination (DCE) for calls to builtin functions
-that may set @code{errno} but are otherwise side-effect free. This flag is
-enabled by default at @option{-O2} and higher if @option{-Os} is not also
+Perform conditional dead code elimination (DCE) for calls to builtin functions
+that may set @code{errno} but are otherwise side-effect free. This flag is
+enabled by default at @option{-O2} and higher if @option{-Os} is not also
specified.
@item -ftree-dominator-opts
contiguously by column, and the original loop iterates over rows,
potentially creating at each access a cache miss. This optimization
applies to all the languages supported by GCC and is not limited to
-Fortran.
+Fortran. To use this code transformation, GCC has to be configured
+with @option{--with-ppl} and @option{--with-cloog} to enable the
+Graphite loop transformation infrastructure.
@item -floop-strip-mine
Perform loop strip mining transformations on loops. Strip mining
-splits a loop into two nested loops. The outer loop has strides
-equal to the strip size and the inner loop has strides of the
+splits a loop into two nested loops. The outer loop has strides
+equal to the strip size and the inner loop has strides of the
original loop within a strip. For example, given a loop like:
@smallexample
DO I = 1, N
ENDDO
@end smallexample
This optimization applies to all the languages supported by GCC and is
-not limited to Fortran.
+not limited to Fortran. To use this code transformation, GCC has to
+be configured with @option{--with-ppl} and @option{--with-cloog} to
+enable the Graphite loop transformation infrastructure.
@item -floop-block
Perform loop blocking transformations on loops. Blocking strip mines
which can be beneficial when @code{M} is larger than the caches,
because the innermost loop will iterate over a smaller amount of data
that can be kept in the caches. This optimization applies to all the
-languages supported by GCC and is not limited to Fortran.
+languages supported by GCC and is not limited to Fortran. To use this
+code transformation, GCC has to be configured with @option{--with-ppl}
+and @option{--with-cloog} to enable the Graphite loop transformation
+infrastructure.
+
+@item -fgraphite-identity
+@opindex fgraphite-identity
+Enable the identity transformation for graphite. For every SCoP we generate
+the polyhedral representation and transform it back to gimple. Using
+@option{-fgraphite-identity} we can check the costs or benefits of the
+GIMPLE -> GRAPHITE -> GIMPLE transformation. Some minimal optimizations
+are also performed by the code generator CLooG, like index splitting and
+dead code elimination in loops.
+
+@item -floop-parallelize-all
+Use the Graphite data dependence analysis to identify loops that can
+be parallelized. Parallelize all the loops that can be analyzed to
+not contain loop carried dependences without checking that it is
+profitable to parallelize the loops.
@item -fcheck-data-deps
@opindex fcheck-data-deps
implies @option{-pthread}, and thus is only supported on targets
that have support for @option{-pthread}.
+@item -ftree-pta
+@opindex ftree-pta
+Perform function-local points-to analysis on trees. This flag is
+enabled by default at @option{-O} and higher.
+
@item -ftree-sra
@opindex ftree-sra
Perform scalar replacement of aggregates. This pass replaces structure
@item -fwhole-program
@opindex fwhole-program
-Assume that the current compilation unit represents whole program being
+Assume that the current compilation unit represents the whole program being
compiled. All public functions and variables with the exception of @code{main}
and those merged by attribute @code{externally_visible} become static functions
-and in a affect gets more aggressively optimized by interprocedural optimizers.
-While this option is equivalent to proper use of @code{static} keyword for
-programs consisting of single file, in combination with option
-@option{--combine} this flag can be used to compile most of smaller scale C
+and in effect are optimized more aggressively by interprocedural optimizers.
+While this option is equivalent to proper use of the @code{static} keyword for
+programs consisting of a single file, in combination with option
+@option{--combine} this flag can be used to compile many smaller scale C
programs since the functions and variables become local for the whole combined
compilation unit, not for the single source file itself.
-This option is not supported for Fortran programs.
+This option implies @option{-fwhole-file} for Fortran programs.
@item -fcprop-registers
@opindex fcprop-registers
Set the directory to search the profile data files in to @var{path}.
This option affects only the profile data generated by
@option{-fprofile-generate}, @option{-ftest-coverage}, @option{-fprofile-arcs}
-and used by @option{-fprofile-use} and @option{-fbranch-probabilities}
+and used by @option{-fprofile-use} and @option{-fbranch-probabilities}
and its related options.
By default, GCC will use the current directory as @var{path}
thus the profile data file will appear in the same directory as the object file.
point. Use @option{-ffloat-store} for such programs, after modifying
them to store all pertinent intermediate computations into variables.
+@item -fexcess-precision=@var{style}
+@opindex fexcess-precision
+This option allows further control over excess precision on machines
+where floating-point registers have more precision than the IEEE
+@code{float} and @code{double} types and the processor does not
+support operations rounding to those types. By default,
+@option{-fexcess-precision=fast} is in effect; this means that
+operations are carried out in the precision of the registers and that
+it is unpredictable when rounding to the types specified in the source
+code takes place. When compiling C, if
+@option{-fexcess-precision=standard} is specified then excess
+precision will follow the rules specified in ISO C99; in particular,
+both casts and assignments cause values to be rounded to their
+semantic types (whereas @option{-ffloat-store} only affects
+assignments). This option is enabled by default for C if a strict
+conformance option such as @option{-std=c99} is used.
+
+@opindex mfpmath
+@option{-fexcess-precision=standard} is not implemented for languages
+other than C, and has no effect if
+@option{-funsafe-math-optimizations} or @option{-ffast-math} is
+specified. On the x86, it also has no effect if @option{-mfpmath=sse}
+or @option{-mfpmath=sse+387} is specified; in the former case, IEEE
+semantics apply without excess precision, and in the latter, rounding
+is unpredictable.
+
@item -ffast-math
@opindex ffast-math
Sets @option{-fno-math-errno}, @option{-funsafe-math-optimizations},
using C99's @code{FENV_ACCESS} pragma. This command line option
will be used to specify the default state for @code{FENV_ACCESS}.
-@item -frtl-abstract-sequences
-@opindex frtl-abstract-sequences
-It is a size optimization method. This option is to find identical
-sequences of code, which can be turned into pseudo-procedures and
-then replace all occurrences with calls to the newly created
-subroutine. It is kind of an opposite of @option{-finline-functions}.
-This optimization runs at RTL level.
-
@item -fsignaling-nans
@opindex fsignaling-nans
Compile code assuming that IEEE signaling NaNs may generate user-visible
@var{name} are given in the following table:
@table @gcctabopt
-@item sra-max-structure-size
-The maximum structure size, in bytes, at which the scalar replacement
-of aggregates (SRA) optimization will perform block copies. The
-default value, 0, implies that GCC will select the most appropriate
-size itself.
-
-@item sra-field-structure-ratio
-The threshold ratio (as a percentage) between instantiated fields and
-the complete structure size. We say that if the ratio of the number
-of bytes in instantiated fields to the number of bytes in the complete
-structure exceeds this parameter, then block copies are not used. The
-default is 75.
-
@item struct-reorg-cold-struct-ratio
The threshold ratio (as a percentage) between a structure frequency
and the frequency of the hottest structure in the program. This parameter
is used by struct-reorg optimization enabled by @option{-fipa-struct-reorg}.
-We say that if the ratio of a structure frequency, calculated by profiling,
-to the hottest structure frequency in the program is less than this
+We say that if the ratio of a structure frequency, calculated by profiling,
+to the hottest structure frequency in the program is less than this
parameter, then structure reorganization is not applied to this structure.
The default is 10.
optimization. If more memory than specified is required, the
optimization will not be done.
-@item max-gcse-passes
-The maximum number of passes of GCSE to run. The default is 1.
-
@item max-pending-list-length
The maximum number of pending dependencies scheduling will allow
before flushing the current state and starting over. Large functions
internal representation) in a single function that the tree inliner
will consider for inlining. This only affects functions declared
inline and methods implemented in a class declaration (C++).
-The default value is 450.
+The default value is 300.
@item max-inline-insns-auto
When you use @option{-finline-functions} (included in @option{-O3}),
by the compiler will be investigated. To those functions, a different
(more restrictive) limit compared to functions declared inline can
be applied.
-The default value is 90.
+The default value is 60.
@item large-function-insns
The limit specifying really large functions. For functions larger than this
whose probability exceeds given threshold (in percents). The default value is
10.
-@item inline-call-cost
-Specify cost of call instruction relative to simple arithmetics operations
-(having cost of 1). Increasing this cost disqualifies inlining of non-leaf
-functions and at the same time increases size of leaf function that is believed to
-reduce function size by being inlined. In effect it increases amount of
-inlining for code having large abstraction penalty (many functions that just
-pass the arguments to other functions) and decrease inlining for code with low
-abstraction penalty. The default value is 12.
+@item early-inlining-insns
+Specify growth that early inliner can make. In effect it increases amount of
+inlining for code having large abstraction penalty. The default value is 12.
+
+@item max-early-inliner-iterations
+@itemx max-early-inliner-iterations
+Limit of iterations of early inliner. This basically bounds number of nested
+indirect calls early inliner can resolve. Deeper chains are still handled by
+late inlining.
@item min-vect-loop-bound
The minimum number of iterations under which a loop will not get vectorized
@item max-cse-insns
The maximum instructions CSE process before flushing. The default is 1000.
-@item max-aliased-vops
-
-Maximum number of virtual operands per function allowed to represent
-aliases before triggering the alias partitioning heuristic. Alias
-partitioning reduces compile times and memory consumption needed for
-aliasing at the expense of precision loss in alias information. The
-default value for this parameter is 100 for -O1, 500 for -O2 and 1000
-for -O3.
-
-Notice that if a function contains more memory statements than the
-value of this parameter, it is not really possible to achieve this
-reduction. In this case, the compiler will use the number of memory
-statements as the value for @option{max-aliased-vops}.
-
-@item avg-aliased-vops
-
-Average number of virtual operands per statement allowed to represent
-aliases before triggering the alias partitioning heuristic. This
-works in conjunction with @option{max-aliased-vops}. If a function
-contains more than @option{max-aliased-vops} virtual operators, then
-memory symbols will be grouped into memory partitions until either the
-total number of virtual operators is below @option{max-aliased-vops}
-or the average number of virtual operators per memory statement is
-below @option{avg-aliased-vops}. The default value for this parameter
-is 1 for -O1 and -O2, and 3 for -O3.
-
@item ggc-min-expand
GCC uses a garbage collector to manage its own memory allocation. This
The default value is 50.
@item selsched-max-sched-times
-The maximum number of times that an instruction will be scheduled during
-selective scheduling. This is the limit on the number of iterations
+The maximum number of times that an instruction will be scheduled during
+selective scheduling. This is the limit on the number of iterations
through which the instruction may be pipelined. The default value is 2.
@item selsched-max-insns-to-rename
@item l2-cache-size
The size of L2 cache, in kilobytes.
+@item min-insn-to-prefetch-ratio
+The minimum ratio between the number of instructions and the
+number of prefetches to enable prefetching in a loop with an
+unknown trip count.
+
+@item prefetch-min-insn-to-mem-ratio
+The minimum ratio between the number of instructions and the
+number of memory references to enable prefetching in a loop.
+
@item use-canonical-types
Whether the compiler should use the ``canonical'' type system. By
default, this should always be 1, which uses a more efficient internal
algorithm do not use pseudo-register conflicts. The default value of
the parameter is 2000.
+@item loop-invariant-max-bbs-in-loop
+Loop invariant motion can be very expensive, both in compile time and
+in amount of needed compile time memory, with very large loops. Loops
+with more basic blocks than this parameter won't have loop invariant
+motion optimization performed on them. The default value of the
+parameter is 1000 for -O1 and 10000 for -O2 and above.
+
@end table
@end table
compilation.
@table @gcctabopt
+@item -Wp,@var{option}
@opindex Wp
You can use @option{-Wp,@var{option}} to bypass the compiler driver
and pass @var{option} directly through to the preprocessor. If
options instead.
@item -Xpreprocessor @var{option}
-@opindex preprocessor
+@opindex Xpreprocessor
Pass @var{option} as an option to the preprocessor. You can use this to
supply system-specific preprocessor options which GCC does not know how to
recognize.
@item -nodefaultlibs
@opindex nodefaultlibs
Do not use the standard system libraries when linking.
-Only the libraries you specify will be passed to the linker.
+Only the libraries you specify will be passed to the linker, options
+specifying linkage of the system libraries, such as @code{-static-libgcc}
+or @code{-shared-libgcc}, will be ignored.
The standard startup files are used normally, unless @option{-nostartfiles}
is used. The compiler may generate calls to @code{memcmp},
@code{memset}, @code{memcpy} and @code{memmove}.
@opindex 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 @code{memcmp}, @code{memset},
+the linker, options specifying linkage of the system libraries, such as
+@code{-static-libgcc} or @code{-shared-libgcc}, will be ignored.
+The compiler may generate calls to @code{memcmp}, @code{memset},
@code{memcpy} and @code{memmove}.
These entries are usually resolved by entries in
libc. These entry points should be supplied through some other
@option{-shared-libgcc}, such that it is linked with the shared
@file{libgcc}.
+@item -static-libstdc++
+When the @command{g++} program is used to link a C++ program, it will
+normally automatically link against @option{libstdc++}. If
+@file{libstdc++} is available as a shared library, and the
+@option{-static} option is not used, then this will link against the
+shared version of @file{libstdc++}. That is normally fine. However, it
+is sometimes useful to freeze the version of @file{libstdc++} used by
+the program without going all the way to a fully static link. The
+@option{-static-libstdc++} option directs the @command{g++} driver to
+link @file{libstdc++} statically, without necessarily linking other
+libraries statically.
+
@item -symbolic
@opindex symbolic
Bind references to global symbols when building a shared object. Warn
@cindex linker script
Use @var{script} as the linker script. This option is supported by most
systems using the GNU linker. On some targets, such as bare-board
-targets without an operating system, the @option{-T} option may be required
+targets without an operating system, the @option{-T} option may be required
when linking to avoid references to undefined symbols.
@item -Xlinker @var{option}
supply system-specific linker options which GCC does not know how to
recognize.
-If you want to pass an option that takes an argument, you must use
+If you want to pass an option that takes a separate argument, you must use
@option{-Xlinker} twice, once for the option and once for the argument.
For example, to pass @option{-assert definitions}, you must write
@samp{-Xlinker -assert -Xlinker definitions}. It does not work to write
@option{-Xlinker "-assert definitions"}, because this passes the entire
string as a single argument, which is not what the linker expects.
+When using the GNU linker, it is usually more convenient to pass
+arguments to linker options using the @option{@var{option}=@var{value}}
+syntax than as separate arguments. For example, you can specify
+@samp{-Xlinker -Map=output.map} rather than
+@samp{-Xlinker -Map -Xlinker output.map}. Other linkers may not support
+this syntax for command-line options.
+
@item -Wl,@var{option}
@opindex Wl
Pass @var{option} as an option to the linker. If @var{option} contains
-commas, it is split into multiple options at the commas.
+commas, it is split into multiple options at the commas. You can use this
+syntax to pass an argument to the option.
+For example, @samp{-Wl,-Map,output.map} passes @samp{-Map output.map} to the
+linker. When using the GNU linker, you can also get the same effect with
+@samp{-Wl,-Map=output.map}.
@item -u @var{symbol}
@opindex u
* Darwin Options::
* DEC Alpha Options::
* DEC Alpha/VMS Options::
+* FR30 Options::
* FRV Options::
* GNU/Linux Options::
* H8/300 Options::
* HPPA Options::
* i386 and x86-64 Options::
+* i386 and x86-64 Windows Options::
* IA-64 Options::
* M32C Options::
* M32R/D Options::
* M680x0 Options::
* M68hc1x Options::
* MCore Options::
+* MeP Options::
* MIPS Options::
* MMIX Options::
* MN10300 Options::
Specifies which floating-point ABI to use. Permissible values
are: @samp{soft}, @samp{softfp} and @samp{hard}.
-Specifying @samp{soft} causes GCC to generate output containing
+Specifying @samp{soft} causes GCC to generate output containing
library calls for floating-point operations.
-@samp{softfp} allows the generation of code using hardware floating-point
-instructions, but still uses the soft-float calling conventions.
-@samp{hard} allows generation of floating-point instructions
+@samp{softfp} allows the generation of code using hardware floating-point
+instructions, but still uses the soft-float calling conventions.
+@samp{hard} allows generation of floating-point instructions
and uses FPU-specific calling conventions.
-Using @option{-mfloat-abi=hard} with VFP coprocessors is not supported.
-Use @option{-mfloat-abi=softfp} with the appropriate @option{-mfpu} option
-to allow the compiler to generate code that makes use of the hardware
-floating-point capabilities for these CPUs.
-
The default depends on the specific target configuration. Note that
the hard-float and soft-float ABIs are not link-compatible; you must
compile your entire program with the same ABI, and link with a
@samp{arm10tdmi}, @samp{arm1020t}, @samp{arm1026ej-s},
@samp{arm10e}, @samp{arm1020e}, @samp{arm1022e},
@samp{arm1136j-s}, @samp{arm1136jf-s}, @samp{mpcore}, @samp{mpcorenovfp},
-@samp{arm1156t2-s}, @samp{arm1176jz-s}, @samp{arm1176jzf-s},
+@samp{arm1156t2-s}, @samp{arm1156t2f-s}, @samp{arm1176jz-s}, @samp{arm1176jzf-s},
@samp{cortex-a8}, @samp{cortex-a9},
@samp{cortex-r4}, @samp{cortex-r4f}, @samp{cortex-m3},
@samp{cortex-m1},
+@samp{cortex-m0},
@samp{xscale}, @samp{iwmmxt}, @samp{iwmmxt2}, @samp{ep9312}.
@item -mtune=@var{name}
@opindex mfp
This specifies what floating point hardware (or hardware emulation) is
available on the target. Permissible names are: @samp{fpa}, @samp{fpe2},
-@samp{fpe3}, @samp{maverick}, @samp{vfp}, @samp{vfpv3}, @samp{vfpv3-d16} and
-@samp{neon}. @option{-mfp} and @option{-mfpe}
+@samp{fpe3}, @samp{maverick}, @samp{vfp}, @samp{vfpv3}, @samp{vfpv3-d16},
+@samp{neon}, and @samp{neon-fp16}. @option{-mfp} and @option{-mfpe}
are synonyms for @option{-mfpu}=@samp{fpe}@var{number}, for compatibility
with older versions of GCC@.
If @option{-msoft-float} is specified this specifies the format of
floating point values.
+@item -mfp16-format=@var{name}
+@opindex mfp16-format
+Specify the format of the @code{__fp16} half-precision floating-point type.
+Permissible names are @samp{none}, @samp{ieee}, and @samp{alternative};
+the default is @samp{none}, in which case the @code{__fp16} type is not
+defined. @xref{Half-Precision}, for more information.
+
@item -mstructure-size-boundary=@var{n}
@opindex mstructure-size-boundary
The size of all structures and unions will be rounded up to a multiple
the compiler generates code to handle function calls via function
pointers.
-@item -mnop-fun-dllimport
-@opindex mnop-fun-dllimport
-Disable support for the @code{dllimport} attribute.
-
@item -msingle-pic-base
@opindex msingle-pic-base
Treat the register used for PIC addressing as read-only, rather than
use the 32-bit ARM instruction set.
This option automatically enables either 16-bit Thumb-1 or
mixed 16/32-bit Thumb-2 instructions based on the @option{-mcpu=@var{name}}
-and @option{-march=@var{name}} options.
+and @option{-march=@var{name}} options. This option is not passed to the
+assembler. If you want to force assembler files to be interpreted as Thumb code,
+either add a @samp{.thumb} directive to the source or pass the @option{-mthumb}
+option directly to the assembler by prefixing it with @option{-Wa}.
@item -mtpcs-frame
@opindex mtpcs-frame
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.
+non-interworking code. This option is not valid in AAPCS configurations
+because interworking is enabled by default.
@item -mcaller-super-interworking
@opindex 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.
+of executing a function pointer if this option is enabled. This option
+is not valid in AAPCS configurations because interworking is enabled
+by default.
@item -mtp=@var{name}
@opindex mtp
Functions prologues/epilogues expanded as call to appropriate
subroutines. Code size will be smaller.
-@item -mno-tablejump
-@opindex mno-tablejump
-Do not generate tablejump insns which sometimes increase code size.
-
@item -mtiny-stack
@opindex mtiny-stack
Change only the low 8 bits of the stack pointer.
@item -mint8
@opindex mint8
Assume int to be 8 bit integer. This affects the sizes of all types: A
-char will be 1 byte, an int will be 1 byte, an long will be 2 bytes
+char will be 1 byte, an int will be 1 byte, a long will be 2 bytes
and long long will be 4 bytes. Please note that this option does not
comply to the C standards, but it will provide you with smaller code
size.
and link scripts will be used to support Core B. This option
defines @code{__BFIN_COREB}. When this option is used, coreb_main
should be used instead of main. It must be used with
-@option{-mmulticore}.
+@option{-mmulticore}.
@item -msdram
@opindex msdram
The Darwin tools vary in their behavior when presented with an ISA
mismatch. The assembler, @file{as}, will only permit instructions to
be used that are valid for the subtype of the file it is generating,
-so you cannot put 64-bit instructions in an @samp{ppc750} object file.
+so you cannot put 64-bit instructions in a @samp{ppc750} object file.
The linker for shared libraries, @file{/usr/bin/libtool}, will fail
and print an error if asked to create a shared library with a less
restrictive subtype than its input files (for instance, trying to put
Schedules as an EV6 and supports the BWX, CIX, FIX, and MAX extensions.
@end table
+Native Linux/GNU toolchains also support the value @samp{native},
+which selects the best architecture option for the host processor.
+@option{-mcpu=native} has no effect if GCC does not recognize
+the processor.
+
@item -mtune=@var{cpu_type}
@opindex mtune
Set only the instruction scheduling parameters for machine type
@var{cpu_type}. The instruction set is not changed.
+Native Linux/GNU toolchains also support the value @samp{native},
+which selects the best architecture option for the host processor.
+@option{-mtune=native} has no effect if GCC does not recognize
+the processor.
+
@item -mmemory-latency=@var{time}
@opindex mmemory-latency
Sets the latency the scheduler should assume for typical memory
@table @gcctabopt
@item -mvms-return-codes
@opindex mvms-return-codes
-Return VMS condition codes from main. The default is to return POSIX
+Return VMS condition codes from main. The default is to return POSIX
style condition (e.g.@: error) codes.
+
+@item -mdebug-main=@var{prefix}
+@opindex mdebug-main=@var{prefix}
+Flag the first routine whose name starts with @var{prefix} as the main
+routine for the debugger.
+
+@item -mmalloc64
+@opindex mmalloc64
+Default to 64bit memory allocation routines.
+@end table
+
+@node FR30 Options
+@subsection FR30 Options
+@cindex FR30 Options
+
+These options are defined specifically for the FR30 port.
+
+@table @gcctabopt
+
+@item -msmall-model
+@opindex msmall-model
+Use the small address space model. This can produce smaller code, but
+it does assume that all symbolic values and addresses will fit into a
+20-bit range.
+
+@item -mno-lsim
+@opindex mno-lsim
+Assume that run-time support has been provided and so there is no need
+to include the simulator library (@file{libsim.a}) on the linker
+command line.
+
@end table
@node FRV Options
command line.
@item -mTLS
-@opindex TLS
+@opindex mTLS
Assume a large TLS segment when generating thread-local code.
@item -mtls
-@opindex tls
+@opindex mtls
Do not assume a large TLS segment when generating thread-local code.
options are available under HP-UX and HI-UX@.
@item -mgnu-ld
-@opindex gnu-ld
+@opindex mgnu-ld
Use GNU ld specific options. This passes @option{-shared} to ld when
building a shared library. It is the default when GCC is configured,
explicitly or implicitly, with the GNU linker. This option does not
on the 64 bit HP-UX GCC, i.e.@: configured with @samp{hppa*64*-*-hpux*}.
@item -mhp-ld
-@opindex hp-ld
+@opindex mhp-ld
Use HP ld specific options. This passes @option{-b} to ld when building
a shared library and passes @option{+Accept TypeMismatch} to ld on all
links. It is the default when GCC is configured, explicitly or
@item core2
Intel Core2 CPU with 64-bit extensions, MMX, SSE, SSE2, SSE3 and SSSE3
instruction set support.
+@item atom
+Intel Atom CPU with 64-bit extensions, MMX, SSE, SSE2, SSE3 and SSSE3
+instruction set support.
@item k6
AMD K6 CPU with MMX instruction set support.
@item k6-2, k6-3
A deprecated synonym for @option{-mtune}.
@item -mfpmath=@var{unit}
-@opindex march
+@opindex mfpmath
Generate floating point arithmetics for selected unit @var{unit}. The choices
for @var{unit} are:
libraries assume that extended precision (80 bit) floating-point operations
are enabled by default; routines in such libraries could suffer significant
loss of accuracy, typically through so-called "catastrophic cancellation",
-when this option is used to set the precision to less than extended precision.
+when this option is used to set the precision to less than extended precision.
@item -mstackrealign
@opindex mstackrealign
In 64-bit mode, SAHF instruction is used to optimize @code{fmod}, @code{drem}
or @code{remainder} built-in functions: see @ref{Other Builtins} for details.
+@item -mmovbe
+@opindex mmovbe
+This option will enable GCC to use movbe instruction to implement
+@code{__builtin_bswap32} and @code{__builtin_bswap64}.
+
+@item -mcrc32
+@opindex mcrc32
+This option will enable built-in functions, @code{__builtin_ia32_crc32qi},
+@code{__builtin_ia32_crc32hi}. @code{__builtin_ia32_crc32si} and
+@code{__builtin_ia32_crc32di} to generate the crc32 machine instruction.
+
@item -mrecip
@opindex mrecip
This option will enable GCC to use RCPSS and RSQRTSS instructions (and their
-vectorized variants RCPPS and RSQRTPS) with an additional Newton-Rhapson step
+vectorized variants RCPPS and RSQRTPS) with an additional Newton-Raphson step
to increase precision instead of DIVSS and SQRTSS (and their vectorized
variants) for single precision floating point arguments. These instructions
are generated only when @option{-funsafe-math-optimizations} is enabled
@option{-funsafe-math-optimizations} have to be enabled. A SVML or ACML ABI
compatible library will have to be specified at link time.
+@item -mabi=@var{name}
+@opindex mabi
+Generate code for the specified calling convention. Permissible values
+are: @samp{sysv} for the ABI used on GNU/Linux and other systems and
+@samp{ms} for the Microsoft ABI. The default is to use the Microsoft
+ABI when targeting Windows. On all other systems, the default is the
+SYSV ABI. You can control this behavior for a specific function by
+using the function attribute @samp{ms_abi}/@samp{sysv_abi}.
+@xref{Function Attributes}.
+
@item -mpush-args
@itemx -mno-push-args
@opindex mpush-args
@option{-mdynamic-no-pic} options.
@item -mno-red-zone
-@opindex no-red-zone
+@opindex 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 location of the
stack pointer that will not be modified by signal or interrupt handlers
Generate code for inline divides of floating point values
using the maximum throughput algorithm.
+@item -mno-inline-float-divide
+@opindex mno-inline-float-divide
+Do not generate inline code for divides of floating point values.
+
@item -minline-int-divide-min-latency
@opindex minline-int-divide-min-latency
Generate code for inline divides of integer values
Generate code for inline divides of integer values
using the maximum throughput algorithm.
+@item -mno-inline-int-divide
+@opindex mno-inline-int-divide
+Do not generate inline code for divides of integer values.
+
@item -minline-sqrt-min-latency
@opindex minline-sqrt-min-latency
Generate code for inline square roots
Generate code for inline square roots
using the maximum throughput algorithm.
+@item -mno-inline-sqrt
+@opindex mno-inline-sqrt
+Do not generate inline code for sqrt.
+
+@item -mfused-madd
+@itemx -mno-fused-madd
+@opindex mfused-madd
+@opindex mno-fused-madd
+Do (don't) generate code that uses the fused multiply/add or multiply/subtract
+instructions. The default is to use these instructions.
+
@item -mno-dwarf2-asm
@itemx -mdwarf2-asm
@opindex mno-dwarf2-asm
Tune the instruction scheduling for a particular CPU, Valid values are
itanium, itanium1, merced, itanium2, and mckinley.
-@item -mt
-@itemx -pthread
-@opindex mt
-@opindex pthread
-Add support for multithreading using the POSIX threads library. This
-option sets flags for both the preprocessor and linker. It does
-not affect the thread safety of object code produced by the compiler or
-that of libraries supplied with it. These are HP-UX specific flags.
-
@item -milp32
@itemx -mlp64
@opindex milp32
This is effective only with @option{-msched-control-spec} enabled.
The default is 'enable'.
-@item -msched-ldc
-@itemx -mno-sched-ldc
-@opindex msched-ldc
-@opindex mno-sched-ldc
-(En/Dis)able use of simple data speculation checks ld.c .
-If disabled, only chk.a instructions will be emitted to check
-data speculative loads.
-The default is 'enable'.
-
-@item -mno-sched-control-ldc
-@itemx -msched-control-ldc
-@opindex mno-sched-control-ldc
-@opindex msched-control-ldc
-(Dis/En)able use of ld.c instructions to check control speculative loads.
-If enabled, in case of control speculative load with no speculatively
-scheduled dependent instructions this load will be emitted as ld.sa and
-ld.c will be used to check it.
-The default is 'disable'.
-
-@item -mno-sched-spec-verbose
-@itemx -msched-spec-verbose
-@opindex mno-sched-spec-verbose
-@opindex msched-spec-verbose
-(Dis/En)able printing of the information about speculative motions.
-
@item -mno-sched-prefer-non-data-spec-insns
@itemx -msched-prefer-non-data-spec-insns
@opindex mno-sched-prefer-non-data-spec-insns
speculation a bit more conservative.
The default is 'disable'.
+@item -msched-spec-ldc
+@opindex msched-spec-ldc
+Use a simple data speculation check. This option is on by default.
+
+@item -msched-control-spec-ldc
+@opindex msched-spec-ldc
+Use a simple check for control speculation. This option is on by default.
+
+@item -msched-stop-bits-after-every-cycle
+@opindex msched-stop-bits-after-every-cycle
+Place a stop bit after every cycle when scheduling. This option is on
+by default.
+
+@item -msched-fp-mem-deps-zero-cost
+@opindex msched-fp-mem-deps-zero-cost
+Assume that floating-point stores and loads are not likely to cause a conflict
+when placed into the same instruction group. This option is disabled by
+default.
+
+@item -msel-sched-dont-check-control-spec
+@opindex msel-sched-dont-check-control-spec
+Generate checks for control speculation in selective scheduling.
+This flag is disabled by default.
+
+@item -msched-max-memory-insns=@var{max-insns}
+@opindex msched-max-memory-insns
+Limit on the number of memory insns per instruction group, giving lower
+priority to subsequent memory insns attempting to schedule in the same
+instruction group. Frequently useful to prevent cache bank conflicts.
+The default value is 1.
+
+@item -msched-max-memory-insns-hard-limit
+@opindex msched-max-memory-insns-hard-limit
+Disallow more than `msched-max-memory-insns' in instruction group.
+Otherwise, limit is `soft' meaning that we would prefer non-memory operations
+when limit is reached but may still schedule memory operations.
+
@end table
@node M32C Options
@multitable @columnfractions 0.20 0.80
@item @strong{Family} @tab @strong{@samp{-mcpu} arguments}
-@item @samp{51qe} @tab @samp{51qe}
+@item @samp{51} @tab @samp{51} @samp{51ac} @samp{51cn} @samp{51em} @samp{51qe}
@item @samp{5206} @tab @samp{5202} @samp{5204} @samp{5206}
@item @samp{5206e} @tab @samp{5206e}
@item @samp{5208} @tab @samp{5207} @samp{5208}
@item @samp{5216} @tab @samp{5214} @samp{5216}
@item @samp{52235} @tab @samp{52230} @samp{52231} @samp{52232} @samp{52233} @samp{52234} @samp{52235}
@item @samp{5225} @tab @samp{5224} @samp{5225}
+@item @samp{52259} @tab @samp{52252} @samp{52254} @samp{52255} @samp{52256} @samp{52258} @samp{52259}
@item @samp{5235} @tab @samp{5232} @samp{5233} @samp{5234} @samp{5235} @samp{523x}
@item @samp{5249} @tab @samp{5249}
@item @samp{5250} @tab @samp{5250}
@item @samp{5272} @tab @samp{5272}
@item @samp{5275} @tab @samp{5274} @samp{5275}
@item @samp{5282} @tab @samp{5280} @samp{5281} @samp{5282} @samp{528x}
+@item @samp{53017} @tab @samp{53011} @samp{53012} @samp{53013} @samp{53014} @samp{53015} @samp{53016} @samp{53017}
@item @samp{5307} @tab @samp{5307}
@item @samp{5329} @tab @samp{5327} @samp{5328} @samp{5329} @samp{532x}
@item @samp{5373} @tab @samp{5372} @samp{5373} @samp{537x}
addressing modes.
@item -minmax
-@itemx -nominmax
+@itemx -mnominmax
@opindex minmax
@opindex mnominmax
Enable the use of 68HC12 min and max instructions.
@opindex m210
@opindex m340
Generate code for the 210 processor.
+
+@item -mno-lsim
+@opindex mno-lsim
+Assume that run-time support has been provided and so omit the
+simulator library (@file{libsim.a)} from the linker command line.
+
+@item -mstack-increment=@var{size}
+@opindex mstack-increment
+Set the maximum amount for a single stack increment operation. Large
+values can increase the speed of programs which contain functions
+that need a large amount of stack space, but they can also trigger a
+segmentation fault if the stack is extended too much. The default
+value is 0x1000.
+
+@end table
+
+@node MeP Options
+@subsection MeP Options
+@cindex MeP options
+
+@table @gcctabopt
+
+@item -mabsdiff
+@opindex mabsdiff
+Enables the @code{abs} instruction, which is the absolute difference
+between two registers.
+
+@item -mall-opts
+@opindex mall-opts
+Enables all the optional instructions - average, multiply, divide, bit
+operations, leading zero, absolute difference, min/max, clip, and
+saturation.
+
+
+@item -maverage
+@opindex maverage
+Enables the @code{ave} instruction, which computes the average of two
+registers.
+
+@item -mbased=@var{n}
+@opindex mbased=
+Variables of size @var{n} bytes or smaller will be placed in the
+@code{.based} section by default. Based variables use the @code{$tp}
+register as a base register, and there is a 128 byte limit to the
+@code{.based} section.
+
+@item -mbitops
+@opindex mbitops
+Enables the bit operation instructions - bit test (@code{btstm}), set
+(@code{bsetm}), clear (@code{bclrm}), invert (@code{bnotm}), and
+test-and-set (@code{tas}).
+
+@item -mc=@var{name}
+@opindex mc=
+Selects which section constant data will be placed in. @var{name} may
+be @code{tiny}, @code{near}, or @code{far}.
+
+@item -mclip
+@opindex mclip
+Enables the @code{clip} instruction. Note that @code{-mclip} is not
+useful unless you also provide @code{-mminmax}.
+
+@item -mconfig=@var{name}
+@opindex mconfig=
+Selects one of the build-in core configurations. Each MeP chip has
+one or more modules in it; each module has a core CPU and a variety of
+coprocessors, optional instructions, and peripherals. The
+@code{MeP-Integrator} tool, not part of GCC, provides these
+configurations through this option; using this option is the same as
+using all the corresponding command line options. The default
+configuration is @code{default}.
+
+@item -mcop
+@opindex mcop
+Enables the coprocessor instructions. By default, this is a 32-bit
+coprocessor. Note that the coprocessor is normally enabled via the
+@code{-mconfig=} option.
+
+@item -mcop32
+@opindex mcop32
+Enables the 32-bit coprocessor's instructions.
+
+@item -mcop64
+@opindex mcop64
+Enables the 64-bit coprocessor's instructions.
+
+@item -mivc2
+@opindex mivc2
+Enables IVC2 scheduling. IVC2 is a 64-bit VLIW coprocessor.
+
+@item -mdc
+@opindex mdc
+Causes constant variables to be placed in the @code{.near} section.
+
+@item -mdiv
+@opindex mdiv
+Enables the @code{div} and @code{divu} instructions.
+
+@item -meb
+@opindex meb
+Generate big-endian code.
+
+@item -mel
+@opindex mel
+Generate little-endian code.
+
+@item -mio-volatile
+@opindex mio-volatile
+Tells the compiler that any variable marked with the @code{io}
+attribute is to be considered volatile.
+
+@item -ml
+@opindex ml
+Causes variables to be assigned to the @code{.far} section by default.
+
+@item -mleadz
+@opindex mleadz
+Enables the @code{leadz} (leading zero) instruction.
+
+@item -mm
+@opindex mm
+Causes variables to be assigned to the @code{.near} section by default.
+
+@item -mminmax
+@opindex mminmax
+Enables the @code{min} and @code{max} instructions.
+
+@item -mmult
+@opindex mmult
+Enables the multiplication and multiply-accumulate instructions.
+
+@item -mno-opts
+@opindex mno-opts
+Disables all the optional instructions enabled by @code{-mall-opts}.
+
+@item -mrepeat
+@opindex mrepeat
+Enables the @code{repeat} and @code{erepeat} instructions, used for
+low-overhead looping.
+
+@item -ms
+@opindex ms
+Causes all variables to default to the @code{.tiny} section. Note
+that there is a 65536 byte limit to this section. Accesses to these
+variables use the @code{%gp} base register.
+
+@item -msatur
+@opindex msatur
+Enables the saturation instructions. Note that the compiler does not
+currently generate these itself, but this option is included for
+compatibility with other tools, like @code{as}.
+
+@item -msdram
+@opindex msdram
+Link the SDRAM-based runtime instead of the default ROM-based runtime.
+
+@item -msim
+@opindex msim
+Link the simulator runtime libraries.
+
+@item -msimnovec
+@opindex msimnovec
+Link the simulator runtime libraries, excluding built-in support
+for reset and exception vectors and tables.
+
+@item -mtf
+@opindex mtf
+Causes all functions to default to the @code{.far} section. Without
+this option, functions default to the @code{.near} section.
+
+@item -mtiny=@var{n}
+@opindex mtiny=
+Variables that are @var{n} bytes or smaller will be allocated to the
+@code{.tiny} section. These variables use the @code{$gp} base
+register. The default for this option is 4, but note that there's a
+65536 byte limit to the @code{.tiny} section.
+
@end table
@node MIPS Options
@samp{24kec}, @samp{24kef2_1}, @samp{24kef1_1},
@samp{34kc}, @samp{34kf2_1}, @samp{34kf1_1},
@samp{74kc}, @samp{74kf2_1}, @samp{74kf1_1}, @samp{74kf3_2},
+@samp{1004kc}, @samp{1004kf2_1}, @samp{1004kf1_1},
@samp{loongson2e}, @samp{loongson2f},
@samp{m4k},
@samp{octeon},
MIPS32 or MIPS64 architecture, it will make use of the MIPS16e ASE@.
MIPS16 code generation can also be controlled on a per-function basis
-by means of @code{mips16} and @code{nomips16} attributes.
+by means of @code{mips16} and @code{nomips16} attributes.
@xref{Function Attributes}, for more information.
@item -mflip-mips16
This option only has an effect when optimizing for the VR4130.
It normally makes code faster, but at the expense of making it bigger.
It is enabled by default at optimization level @option{-O3}.
+
+@item -msynci
+@itemx -mno-synci
+@opindex msynci
+Enable (disable) generation of @code{synci} instructions on
+architectures that support it. The @code{synci} instructions (if
+enabled) will be generated when @code{__builtin___clear_cache()} is
+compiled.
+
+This option defaults to @code{-mno-synci}, but the default can be
+overridden by configuring with @code{--with-synci}.
+
+When compiling code for single processor systems, it is generally safe
+to use @code{synci}. However, on many multi-core (SMP) systems, it
+will not invalidate the instruction caches on all cores and may lead
+to undefined behavior.
@end table
@node MMIX Options
@item -mabi=mmixware
@itemx -mabi=gnu
-@opindex mabi-mmixware
+@opindex mabi=mmixware
@opindex mabi=gnu
Generate code that passes function parameters and return values that (in
the called function) are seen as registers @code{$0} and up, as opposed to
Generate code for a PDP-11/10.
@item -mbcopy-builtin
-@opindex bcopy-builtin
+@opindex mbcopy-builtin
Use inline @code{movmemhi} patterns for copying memory. This is the
default.
@itemx -mno-mfcrf
@itemx -mpopcntb
@itemx -mno-popcntb
+@itemx -mpopcntd
+@itemx -mno-popcntd
@itemx -mfprnd
@itemx -mno-fprnd
@itemx -mcmpb
@opindex mno-mfcrf
@opindex mpopcntb
@opindex mno-popcntb
+@opindex mpopcntd
+@opindex mno-popcntd
@opindex mfprnd
@opindex mno-fprnd
@opindex mcmpb
double precision FP reciprocal estimate instruction implemented on the
POWER5 processor and other processors that support the PowerPC V2.02
architecture.
+The @option{-mpopcntd} option allows GCC to generate the popcount
+instruction implemented on the POWER7 processor and other processors
+that support the PowerPC V2.06 architecture.
The @option{-mfprnd} option allows GCC to generate the FP round to
integer instructions implemented on the POWER5+ processor and other
processors that support the PowerPC V2.03 architecture.
following options:
@gccoptlist{-maltivec -mfprnd -mhard-float -mmfcrf -mmultiple @gol
--mnew-mnemonics -mpopcntb -mpower -mpower2 -mpowerpc64 @gol
+-mnew-mnemonics -mpopcntb -mpopcntd -mpower -mpower2 -mpowerpc64 @gol
-mpowerpc-gpopt -mpowerpc-gfxopt -msingle-float -mdouble-float @gol
--msimple-fpu -mstring -mmulhw -mdlmzb -mmfpgpr}
+-msimple-fpu -mstring -mmulhw -mdlmzb -mmfpgpr -mvsx}
The particular options set for any particular CPU will vary between
compiler versions, depending on what setting seems to produce optimal
This option has been deprecated. Use @option{-mspe} and
@option{-mno-spe} instead.
+@item -mvsx
+@itemx -mno-vsx
+@opindex mvsx
+@opindex mno-vsx
+Generate code that uses (does not use) vector/scalar (VSX)
+instructions, and also enable the use of built-in functions that allow
+more direct access to the VSX instruction set.
+
@item -mfloat-gprs=@var{yes/single/double/no}
@itemx -mfloat-gprs
@opindex mfloat-gprs
@itemx -mdouble-float
@opindex msingle-float
@opindex mdouble-float
-Generate code for single or double-precision floating point operations.
-@option{-mdouble-float} implies @option{-msingle-float}.
+Generate code for single or double-precision floating point operations.
+@option{-mdouble-float} implies @option{-msingle-float}.
@item -msimple-fpu
@opindex msimple-fpu
@item -mfpu
@opindex mfpu
-Specify type of floating point unit. Valid values are @var{sp_lite}
+Specify type of floating point unit. Valid values are @var{sp_lite}
(equivalent to -msingle-float -msimple-fpu), @var{dp_lite} (equivalent
to -mdouble-float -msimple-fpu), @var{sp_full} (equivalent to -msingle-float),
and @var{dp_full} (equivalent to -mdouble-float).
default unless you configured GCC using @samp{powerpc-*-eabiaix}.
@item -mcall-sysv-eabi
+@itemx -mcall-eabi
@opindex mcall-sysv-eabi
+@opindex mcall-eabi
Specify both @option{-mcall-sysv} and @option{-meabi} options.
@item -mcall-sysv-noeabi
@opindex mcall-sysv-noeabi
Specify both @option{-mcall-sysv} and @option{-mno-eabi} options.
-@item -mcall-solaris
-@opindex mcall-solaris
-On System V.4 and embedded PowerPC systems compile code for the Solaris
+@item -mcall-aixdesc
+@opindex m
+On System V.4 and embedded PowerPC systems compile code for the AIX
operating system.
@item -mcall-linux
On System V.4 and embedded PowerPC systems compile code for the
Hurd-based GNU system.
+@item -mcall-freebsd
+@opindex mcall-freebsd
+On System V.4 and embedded PowerPC systems compile code for the
+FreeBSD operating system.
+
@item -mcall-netbsd
@opindex mcall-netbsd
On System V.4 and embedded PowerPC systems compile code for the
NetBSD operating system.
+@item -mcall-openbsd
+@opindex mcall-netbsd
+On System V.4 and embedded PowerPC systems compile code for the
+OpenBSD operating system.
+
@item -maix-struct-return
@opindex maix-struct-return
Return all structures in memory (as specified by the AIX ABI)@.
compile code the same as @option{-msdata=eabi}, otherwise compile code the
same as @option{-msdata=sysv}.
-@item -msdata-data
-@opindex msdata-data
+@item -msdata=data
+@opindex msdata=data
On System V.4 and embedded PowerPC systems, put small global
data in the @samp{.sdata} section. Put small uninitialized global
data in the @samp{.sbss} section. Do not use register @code{r13}
In the future, we may cause GCC to ignore all longcall specifications
when the linker is known to generate glue.
+@item -mtls-markers
+@itemx -mno-tls-markers
+@opindex mtls-markers
+@opindex mno-tls-markers
+Mark (do not mark) calls to @code{__tls_get_addr} with a relocation
+specifying the function argument. The relocation allows ld to
+reliably associate function call with argument setup instructions for
+TLS optimization, which in turn allows gcc to better schedule the
+sequence.
+
@item -pthread
@opindex pthread
Adds support for multithreading with the @dfn{pthreads} library.
@item -mel
@opindex mel
-Compile code for little endian mode.
+Compile code for little endian mode.
@item -mnhwloop
@opindex mnhwloop
@item -mmac
@opindex mmac
-Enable the use of multiply-accumulate instructions. Disabled by default.
+Enable the use of multiply-accumulate instructions. Disabled by default.
@item -mscore5
@opindex mscore5
@item -m2e
Generate code for the SH2e.
+@item -m2a-nofpu
+@opindex m2a-nofpu
+Generate code for the SH2a without FPU, or for a SH2a-FPU in such a way
+that the floating-point unit is not used.
+
+@item -m2a-single-only
+@opindex m2a-single-only
+Generate code for the SH2a-FPU, in such a way that no double-precision
+floating point operations are used.
+
+@item -m2a-single
+@opindex m2a-single
+Generate code for the SH2a-FPU assuming the floating-point unit is in
+single-precision mode by default.
+
+@item -m2a
+@opindex m2a
+Generate code for the SH2a-FPU assuming the floating-point unit is in
+double-precision mode by default.
+
@item -m3
@opindex m3
Generate code for the SH3.
@item -mfmovd
@opindex mfmovd
-Enable the use of the instruction @code{fmovd}.
+Enable the use of the instruction @code{fmovd}. Check @option{-mdalign} for
+alignment constraints.
@item -mhitachi
@opindex mhitachi
@opindex mhint-max-distance
The encoding of the branch hint instruction limits the hint to be within
256 instructions of the branch it is effecting. By default, GCC makes
-sure it is within 125.
+sure it is within 125.
@item -msafe-hints
@opindex msafe-hints
These are listed under @xref{i386 and x86-64 Options}.
+@node i386 and x86-64 Windows Options
+@subsection i386 and x86-64 Windows Options
+@cindex i386 and x86-64 Windows Options
+
+These additional options are available for Windows targets:
+
+@table @gcctabopt
+@item -mconsole
+@opindex mconsole
+This option is available for Cygwin and MinGW targets. It
+specifies that a console application is to be generated, by
+instructing the linker to set the PE header subsystem type
+required for console applications.
+This is the default behavior for Cygwin and MinGW targets.
+
+@item -mcygwin
+@opindex mcygwin
+This option is available for Cygwin targets. It specifies that
+the Cygwin internal interface is to be used for predefined
+preprocessor macros, C runtime libraries and related linker
+paths and options. For Cygwin targets this is the default behavior.
+This option is deprecated and will be removed in a future release.
+
+@item -mno-cygwin
+@opindex mno-cygwin
+This option is available for Cygwin targets. It specifies that
+the MinGW internal interface is to be used instead of Cygwin's, by
+setting MinGW-related predefined macros and linker paths and default
+library options.
+This option is deprecated and will be removed in a future release.
+
+@item -mdll
+@opindex mdll
+This option is available for Cygwin and MinGW targets. It
+specifies that a DLL - a dynamic link library - is to be
+generated, enabling the selection of the required runtime
+startup object and entry point.
+
+@item -mnop-fun-dllimport
+@opindex mnop-fun-dllimport
+This option is available for Cygwin and MinGW targets. It
+specifies that the dllimport attribute should be ignored.
+
+@item -mthread
+@opindex mthread
+This option is available for MinGW targets. It specifies
+that MinGW-specific thread support is to be used.
+
+@item -municode
+@opindex municode
+This option is available for mingw-w64 targets. It specifies
+that the UNICODE macro is getting pre-defined and that the
+unicode capable runtime startup code is choosen.
+
+@item -mwin32
+@opindex mwin32
+This option is available for Cygwin and MinGW targets. It
+specifies that the typical Windows pre-defined macros are to
+be set in the pre-processor, but does not influence the choice
+of runtime library/startup code.
+
+@item -mwindows
+@opindex mwindows
+This option is available for Cygwin and MinGW targets. It
+specifies that a GUI application is to be generated by
+instructing the linker to set the PE header subsystem type
+appropriately.
+
+@item -mpe-aligned-commons
+@opindex mpe-aligned-commons
+This option is available for Cygwin and MinGW targets. It
+specifies that the GNU extension to the PE file format that
+permits the correct alignment of COMMON variables should be
+used when generating code. It will be enabled by default if
+GCC detects that the target assembler found during configuration
+supports the feature.
+@end table
+
+See also under @ref{i386 and x86-64 Options} for standard options.
+
@node Xstormy16 Options
@subsection Xstormy16 Options
@cindex Xstormy16 Options
@item -fno-common
@opindex fno-common
-In C, allocate even uninitialized global variables in the data section of the
-object file, rather than generating them as common blocks. This has the
-effect that if the same variable is declared (without @code{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.
+In C code, controls the placement of uninitialized global variables.
+Unix C compilers have traditionally permitted multiple definitions of
+such variables in different compilation units by placing the variables
+in a common block.
+This is the behavior specified by @option{-fcommon}, and is the default
+for GCC on most targets.
+On the other hand, this behavior is not required by ISO C, and on some
+targets may carry a speed or code size penalty on variable references.
+The @option{-fno-common} option specifies that the compiler should place
+uninitialized global variables in the data section of the object file,
+rather than generating them as common blocks.
+This has the effect that if the same variable is declared
+(without @code{extern}) in two different compilations,
+you will get a multiple-definition error when you link them.
+In this case, you must compile with @option{-fcommon} instead.
+Compiling with @option{-fno-common} is useful on targets for which
+it provides better performance, or if you wish to verify that the
+program will work on other systems which always treat uninitialized
+variable declarations this way.
@item -fno-ident
@opindex fno-ident
name, such as @code{vector<int> blah(const vector<int> &)}, not the
internal mangled name (e.g., @code{_Z4blahRSt6vectorIiSaIiEE}). The
match is done on substrings: if the @var{sym} parameter is a substring
-of the function name, it is considered to be a match.
+of the function name, it is considered to be a match. For C99 and C++
+extended identifiers, the function name must be given in UTF-8, not
+using universal character names.
@item -fstack-check
@opindex fstack-check
behavior for the options. For instance, if you use @option{-g} to
generate the precompiled header but not when using it, you may or may
not get debugging information for routines in the precompiled header.
-
-@node Running Protoize
-@section Running Protoize
-
-The program @code{protoize} is an optional part of GCC@. You can use
-it to add prototypes to a program, thus converting the program to ISO
-C in one respect. The companion program @code{unprotoize} does the
-reverse: it removes argument types from any prototypes that are found.
-
-When you run these programs, you must specify a set of source files as
-command line arguments. The conversion programs start out by compiling
-these files to see what functions they define. The information gathered
-about a file @var{foo} is saved in a file named @file{@var{foo}.X}.
-
-After scanning comes actual conversion. The specified files are all
-eligible to be converted; any files they include (whether sources or
-just headers) are eligible as well.
-
-But not all the eligible files are converted. By default,
-@code{protoize} and @code{unprotoize} convert only source and header
-files in the current directory. You can specify additional directories
-whose files should be converted with the @option{-d @var{directory}}
-option. You can also specify particular files to exclude with the
-@option{-x @var{file}} option. A file is converted if it is eligible, its
-directory name matches one of the specified directory names, and its
-name within the directory has not been excluded.
-
-Basic conversion with @code{protoize} consists of rewriting most
-function definitions and function declarations to specify the types of
-the arguments. The only ones not rewritten are those for varargs
-functions.
-
-@code{protoize} optionally inserts prototype declarations at the
-beginning of the source file, to make them available for any calls that
-precede the function's definition. Or it can insert prototype
-declarations with block scope in the blocks where undeclared functions
-are called.
-
-Basic conversion with @code{unprotoize} consists of rewriting most
-function declarations to remove any argument types, and rewriting
-function definitions to the old-style pre-ISO form.
-
-Both conversion programs print a warning for any function declaration or
-definition that they can't convert. You can suppress these warnings
-with @option{-q}.
-
-The output from @code{protoize} or @code{unprotoize} replaces the
-original source file. The original file is renamed to a name ending
-with @samp{.save} (for DOS, the saved filename ends in @samp{.sav}
-without the original @samp{.c} suffix). If the @samp{.save} (@samp{.sav}
-for DOS) file already exists, then the source file is simply discarded.
-
-@code{protoize} and @code{unprotoize} both depend on GCC itself to
-scan the program and collect information about the functions it uses.
-So neither of these programs will work until GCC is installed.
-
-Here is a table of the options you can use with @code{protoize} and
-@code{unprotoize}. Each option works with both programs unless
-otherwise stated.
-
-@table @code
-@item -B @var{directory}
-Look for the file @file{SYSCALLS.c.X} in @var{directory}, instead of the
-usual directory (normally @file{/usr/local/lib}). This file contains
-prototype information about standard system functions. This option
-applies only to @code{protoize}.
-
-@item -c @var{compilation-options}
-Use @var{compilation-options} as the options when running @command{gcc} to
-produce the @samp{.X} files. The special option @option{-aux-info} is
-always passed in addition, to tell @command{gcc} to write a @samp{.X} file.
-
-Note that the compilation options must be given as a single argument to
-@code{protoize} or @code{unprotoize}. If you want to specify several
-@command{gcc} options, you must quote the entire set of compilation options
-to make them a single word in the shell.
-
-There are certain @command{gcc} arguments that you cannot use, because they
-would produce the wrong kind of output. These include @option{-g},
-@option{-O}, @option{-c}, @option{-S}, and @option{-o} If you include these in
-the @var{compilation-options}, they are ignored.
-
-@item -C
-Rename files to end in @samp{.C} (@samp{.cc} for DOS-based file
-systems) instead of @samp{.c}. This is convenient if you are converting
-a C program to C++. This option applies only to @code{protoize}.
-
-@item -g
-Add explicit global declarations. This means inserting explicit
-declarations at the beginning of each source file for each function
-that is called in the file and was not declared. These declarations
-precede the first function definition that contains a call to an
-undeclared function. This option applies only to @code{protoize}.
-
-@item -i @var{string}
-Indent old-style parameter declarations with the string @var{string}.
-This option applies only to @code{protoize}.
-
-@code{unprotoize} converts prototyped function definitions to old-style
-function definitions, where the arguments are declared between the
-argument list and the initial @samp{@{}. By default, @code{unprotoize}
-uses five spaces as the indentation. If you want to indent with just
-one space instead, use @option{-i " "}.
-
-@item -k
-Keep the @samp{.X} files. Normally, they are deleted after conversion
-is finished.
-
-@item -l
-Add explicit local declarations. @code{protoize} with @option{-l} inserts
-a prototype declaration for each function in each block which calls the
-function without any declaration. This option applies only to
-@code{protoize}.
-
-@item -n
-Make no real changes. This mode just prints information about the conversions
-that would have been done without @option{-n}.
-
-@item -N
-Make no @samp{.save} files. The original files are simply deleted.
-Use this option with caution.
-
-@item -p @var{program}
-Use the program @var{program} as the compiler. Normally, the name
-@file{gcc} is used.
-
-@item -q
-Work quietly. Most warnings are suppressed.
-
-@item -v
-Print the version number, just like @option{-v} for @command{gcc}.
-@end table
-
-If you need special compiler options to compile one of your program's
-source files, then you should generate that file's @samp{.X} file
-specially, by running @command{gcc} on that source file with the
-appropriate options and the option @option{-aux-info}. Then run
-@code{protoize} on the entire set of files. @code{protoize} will use
-the existing @samp{.X} file because it is newer than the source file.
-For example:
-
-@smallexample
-gcc -Dfoo=bar file1.c -aux-info file1.X
-protoize *.c
-@end smallexample
-
-@noindent
-You need to include the special files along with the rest in the
-@code{protoize} command, even though their @samp{.X} files already
-exist, because otherwise they won't get converted.
-
-@xref{Protoize Caveats}, for more information on how to use
-@code{protoize} successfully.
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