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
@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{[},@dots{}@r{]]} --target-help @gol
---version -wrapper@@@var{file}}
+--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
-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 -Wunused-value -Wunused-variable @gol
-Wvariadic-macros -Wvla @gol
-Wvolatile-register-var -Wwrite-strings}
-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
-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}
@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
-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
-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
@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
-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 -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
@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}
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
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
-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
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
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
@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
@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-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
@item -fdump-statistics-@var{option}
@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
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}.
+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
@opindex time
Report the CPU time taken by each subprocess in the compilation
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
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-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.
Transposing is enabled only if profiling information is available.
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
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 -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
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
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
* H8/300 Options::
* HPPA Options::
* i386 and x86-64 Options::
+* i386 and x86-64 Windows Options::
* IA-64 Options::
* M32C Options::
* M32R/D Options::
@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},
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
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.
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
@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:
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 -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
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}
@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 progrqams which contain functions
+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.
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.
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
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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