@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
@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{i386 and x86-64 Windows Options}
@gccoptlist{-mconsole -mcygwin -mno-cygwin -mdll
--mnop-fun-dllimport -mthread -mwin32 -mwindows}
+-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
@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
@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
attempts to change the order of the matrix's dimensions in order to
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
@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},
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
@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
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}
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)@.
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.
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 behaviour for Cygwin and MinGW targets.
+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 behaviour.
+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
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 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.
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
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