-pedantic-errors @gol
-w -Wextra -Wall -Waddress -Waggregate-return @gol
-Waggressive-loop-optimizations -Warray-bounds -Warray-bounds=@var{n} @gol
--Wbool-compare -Wframe-address @gol
+-Wbool-compare -Wduplicated-cond -Wframe-address @gol
-Wno-attributes -Wno-builtin-macro-redefined @gol
-Wc90-c99-compat -Wc99-c11-compat @gol
-Wc++-compat -Wc++11-compat -Wc++14-compat -Wcast-align -Wcast-qual @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-backprop@r{[}-@var{n}@r{]} @gol
-fdump-tree-forwprop@r{[}-@var{n}@r{]} @gol
-fdump-tree-nrv -fdump-tree-vect @gol
-fdump-tree-sink @gol
-fira-loop-pressure -fno-ira-share-save-slots @gol
-fno-ira-share-spill-slots -fira-verbose=@var{n} @gol
-fisolate-erroneous-paths-dereference -fisolate-erroneous-paths-attribute @gol
--fivopts -fkeep-inline-functions -fkeep-static-consts @gol
--flive-range-shrinkage @gol
+-fivopts -fkeep-inline-functions -fkeep-static-functions @gol
+-fkeep-static-consts -flive-range-shrinkage @gol
-floop-block -floop-interchange -floop-strip-mine @gol
-floop-unroll-and-jam -floop-nest-optimize @gol
-floop-parallelize-all -flra-remat -flto -flto-compression-level @gol
-fprofile-use -fprofile-use=@var{path} -fprofile-values @gol
-fprofile-reorder-functions @gol
-freciprocal-math -free -frename-registers -freorder-blocks @gol
+-freorder-blocks-algorithm=@var{algorithm} @gol
-freorder-blocks-and-partition -freorder-functions @gol
-frerun-cse-after-loop -freschedule-modulo-scheduled-loops @gol
-frounding-math -fsched2-use-superblocks -fsched-pressure @gol
-fschedule-insns -fschedule-insns2 -fsection-anchors @gol
-fselective-scheduling -fselective-scheduling2 @gol
-fsel-sched-pipelining -fsel-sched-pipelining-outer-loops @gol
--fsemantic-interposition @gol
--fshrink-wrap -fsignaling-nans -fsingle-precision-constant @gol
--fsplit-ivs-in-unroller -fsplit-wide-types -fssa-phiopt @gol
+-fsemantic-interposition -fshrink-wrap -fsignaling-nans @gol
+-fsingle-precision-constant -fsplit-ivs-in-unroller @gol
+-fsplit-wide-types -fssa-backprop -fssa-phiopt @gol
-fstack-protector -fstack-protector-all -fstack-protector-strong @gol
-fstack-protector-explicit -fstdarg-opt -fstrict-aliasing @gol
-fstrict-overflow -fthread-jumps -ftracer -ftree-bit-ccp @gol
-mbranch-cost=@var{num} -mbranch-likely -mno-branch-likely @gol
-mfp-exceptions -mno-fp-exceptions @gol
-mvr4130-align -mno-vr4130-align -msynci -mno-synci @gol
--mrelax-pic-calls -mno-relax-pic-calls -mmcount-ra-address}
+-mrelax-pic-calls -mno-relax-pic-calls -mmcount-ra-address @gol
+-mframe-header-opt -mno-frame-header-opt}
@emph{MMIX Options}
@gccoptlist{-mlibfuncs -mno-libfuncs -mepsilon -mno-epsilon -mabi=gnu @gol
@emph{MSP430 Options}
@gccoptlist{-msim -masm-hex -mmcu= -mcpu= -mlarge -msmall -mrelax @gol
-mcode-region= -mdata-region= @gol
+-msilicon-errata= -msilicon-errata-warn= @gol
-mhwmult= -minrt}
@emph{NDS32 Options}
-mrecip -mrecip=@var{opt} @gol
-mvzeroupper -mprefer-avx128 @gol
-mmmx -msse -msse2 -msse3 -mssse3 -msse4.1 -msse4.2 -msse4 -mavx @gol
--mavx2 -mavx512f -mavx512pf -mavx512er -mavx512cd -msha @gol
--maes -mpclmul -mfsgsbase -mrdrnd -mf16c -mfma -mprefetchwt1 @gol
--mclflushopt -mxsavec -mxsaves @gol
+-mavx2 -mavx512f -mavx512pf -mavx512er -mavx512cd -mavx512vl @gol
+-mavx512bw -mavx512dq -mavx512ifma -mavx512vbmi -msha -maes @gol
+-mpclmul -mfsgsbase -mrdrnd -mf16c -mfma @gol
+-mprefetchwt1 -mclflushopt -mxsavec -mxsaves @gol
-msse4a -m3dnow -mpopcnt -mabm -mbmi -mtbm -mfma4 -mxop -mlzcnt @gol
-mbmi2 -mfxsr -mxsave -mxsaveopt -mrtm -mlwp -mmpx -mmwaitx -mthreads @gol
-mno-align-stringops -minline-all-stringops @gol
might compile a file @file{firstClass.C} like this:
@smallexample
-g++ -g -frepo -O -c firstClass.C
+g++ -g -fstrict-enums -O -c firstClass.C
@end smallexample
@noindent
-In this example, only @option{-frepo} is an option meant
+In this example, only @option{-fstrict-enums} is an option meant
only for C++ programs; you can use the other options with any
language supported by GCC@.
-Wimplicit-int @r{(C and Objective-C only)} @gol
-Wimplicit-function-declaration @r{(C and Objective-C only)} @gol
-Wbool-compare @gol
+-Wduplicated-cond @gol
-Wcomment @gol
-Wformat @gol
-Wmain @r{(only for C/ObjC and unless} @option{-ffreestanding}@r{)} @gol
@end smallexample
This warning is enabled by @option{-Wall}.
+@item -Wduplicated-cond
+@opindex Wno-duplicated-cond
+@opindex Wduplicated-cond
+Warn about duplicated conditions in an if-else-if chain. For instance,
+warn for the following code:
+@smallexample
+if (p->q != NULL) @{ @dots{} @}
+else if (p->q != NULL) @{ @dots{} @}
+@end smallexample
+This warning is enabled by @option{-Wall}.
+
@item -Wframe-address
@opindex Wno-frame-address
@opindex Wframe-address
Enable AddressSanitizer, a fast memory error detector.
Memory access instructions are instrumented to detect
out-of-bounds and use-after-free bugs.
-See @uref{http://code.google.com/p/address-sanitizer/} for
+See @uref{https://github.com/google/sanitizers/wiki/AddressSanitizer} for
more details. The run-time behavior can be influenced using the
-@env{ASAN_OPTIONS} environment variable; see
-@url{https://code.google.com/p/address-sanitizer/wiki/Flags#Run-time_flags} for
-a list of supported options.
+@env{ASAN_OPTIONS} environment variable. When set to @code{help=1},
+the available options are shown at startup of the instrumended program. See
+@url{https://github.com/google/sanitizers/wiki/AddressSanitizerFlags#run-time-flags}
+for a list of supported options.
@item -fsanitize=kernel-address
@opindex fsanitize=kernel-address
Enable AddressSanitizer for Linux kernel.
-See @uref{http://code.google.com/p/address-sanitizer/wiki/AddressSanitizerForKernel} for more details.
+See @uref{https://github.com/google/kasan/wiki} for more details.
@item -fsanitize=thread
@opindex fsanitize=thread
Enable ThreadSanitizer, a fast data race detector.
Memory access instructions are instrumented to detect
-data race bugs. See @uref{http://code.google.com/p/thread-sanitizer/} for more
+data race bugs. See @uref{https://github.com/google/sanitizers/wiki#threadsanitizer} for more
details. The run-time behavior can be influenced using the @env{TSAN_OPTIONS}
environment variable; see
-@url{https://code.google.com/p/thread-sanitizer/wiki/Flags} for a list of
+@url{https://github.com/google/sanitizers/wiki/ThreadSanitizerFlags} for a list of
supported options.
@item -fsanitize=leak
@option{-fsanitize=address} nor @option{-fsanitize=thread} is used. In that
case the executable is linked against a library that overrides @code{malloc}
and other allocator functions. See
-@uref{https://code.google.com/p/address-sanitizer/wiki/LeakSanitizer} for more
+@uref{https://github.com/google/sanitizers/wiki/AddressSanitizerLeakSanitizer} for more
details. The run-time behavior can be influenced using the
@env{LSAN_OPTIONS} environment variable.
Dump each function after optimizing PHI nodes into straightline code. The file
name is made by appending @file{.phiopt} to the source file name.
+@item backprop
+@opindex fdump-tree-backprop
+Dump each function after back-propagating use information up the definition
+chain. The file name is made by appending @file{.backprop} to the
+source file name.
+
@item forwprop
@opindex fdump-tree-forwprop
Dump each function after forward propagating single use variables. The file
Dump each function after Value Range Propagation (VRP). The file name
is made by appending @file{.vrp} to the source file name.
+@item oaccdevlow
+@opindex fdump-tree-oaccdevlow
+Dump each function after applying device-specific OpenACC transformations.
+The file name is made by appending @file{.oaccdevlow} to the source file name.
+
@item all
@opindex fdump-tree-all
Enable all the available tree dumps with the flags provided in this option.
-fipa-reference @gol
-fmerge-constants @gol
-fmove-loop-invariants @gol
+-freorder-blocks @gol
-fshrink-wrap @gol
-fsplit-wide-types @gol
+-fssa-backprop @gol
+-fssa-phiopt @gol
-ftree-bit-ccp @gol
-ftree-ccp @gol
--fssa-phiopt @gol
-ftree-ch @gol
-ftree-coalesce-vars @gol
-ftree-copy-prop @gol
-foptimize-strlen @gol
-fpartial-inlining @gol
-fpeephole2 @gol
--freorder-blocks -freorder-blocks-and-partition -freorder-functions @gol
+-freorder-blocks-algorithm=stc @gol
+-freorder-blocks-and-partition -freorder-functions @gol
-frerun-cse-after-loop @gol
-fsched-interblock -fsched-spec @gol
-fschedule-insns -fschedule-insns2 @gol
@option{-Os} disables the following optimization flags:
@gccoptlist{-falign-functions -falign-jumps -falign-loops @gol
--falign-labels -freorder-blocks -freorder-blocks-and-partition @gol
--fprefetch-loop-arrays}
+-falign-labels -freorder-blocks -freorder-blocks-algorithm=stc @gol
+-freorder-blocks-and-partition -fprefetch-loop-arrays}
@item -Ofast
@opindex Ofast
@code{extern inline} extension in GNU C90@. In C++, emit any and all
inline functions into the object file.
+@item -fkeep-static-functions
+@opindex fkeep-static-functions
+Emit @code{static} functions into the object file, even if the function
+is never used.
+
@item -fkeep-static-consts
@opindex fkeep-static-consts
Emit variables declared @code{static const} when optimization isn't turned
pass only operates on local scalar variables and is enabled by default
at @option{-O} and higher.
+@item -fssa-backprop
+@opindex fssa-backprop
+Propagate information about uses of a value up the definition chain
+in order to simplify the definitions. For example, this pass strips
+sign operations if the sign of a value never matters. The flag is
+enabled by default at @option{-O} and higher.
+
@item -fssa-phiopt
@opindex fssa-phiopt
Perform pattern matching on SSA PHI nodes to optimize conditional
@item -ftree-coalesce-vars
@opindex ftree-coalesce-vars
-Tell the compiler to attempt to combine small user-defined variables
-too, instead of just compiler temporaries. This may severely limit the
-ability to debug an optimized program compiled with
+While transforming the program out of the SSA representation, attempt to
+reduce copying by coalescing versions of different user-defined
+variables, instead of just compiler temporaries. This may severely
+limit the ability to debug an optimized program compiled with
@option{-fno-var-tracking-assignments}. In the negated form, this flag
prevents SSA coalescing of user variables. This option is enabled by
-default if optimization is enabled.
+default if optimization is enabled, and it does very little otherwise.
@item -ftree-loop-if-convert
@opindex ftree-loop-if-convert
Reorder basic blocks in the compiled function in order to reduce number of
taken branches and improve code locality.
-Enabled at levels @option{-O2}, @option{-O3}.
+Enabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os}.
+
+@item -freorder-blocks-algorithm=@var{algorithm}
+@opindex freorder-blocks-algorithm
+Use the specified algorithm for basic block reordering. The
+@var{algorithm} argument can be @samp{simple}, which does not increase
+code size (except sometimes due to secondary effects like alignment),
+or @samp{stc}, the ``software trace cache'' algorithm, which tries to
+put all often executed code together, minimizing the number of branches
+executed by making extra copies of code.
+
+The default is @samp{simple} at levels @option{-O}, @option{-Os}, and
+@samp{stc} at levels @option{-O2}, @option{-O3}.
@item -freorder-blocks-and-partition
@opindex freorder-blocks-and-partition
Chunk size of omp schedule for loops parallelized by parloops. The default
is 0.
+@item parloops-schedule
+Schedule type of omp schedule for loops parallelized by parloops (static,
+dynamic, guided, auto, runtime). The default is static.
+
+@item max-ssa-name-query-depth
+Maximum depth of recursion when querying properties of SSA names in things
+like fold routines. One level of recursion corresponds to following a
+use-def chain.
@end table
@end table
The default is @option{-mno-mcount-ra-address}.
+@item -mframe-header-opt
+@itemx -mno-frame-header-opt
+@opindex mframe-header-opt
+Enable (disable) frame header optimization in the o32 ABI. When using the
+o32 ABI, calling functions will allocate 16 bytes on the stack for the called
+function to write out register arguments. When enabled, this optimization
+will suppress the allocation of the frame header if it can be determined that
+it is unused.
+
+This optimization is off by default at all optimization levels.
+
@end table
@node MMIX Options
A value of @samp{auto} can also be given. This tells GCC to deduce
the hardware multiply support based upon the MCU name provided by the
@option{-mmcu} option. If no @option{-mmcu} option is specified then
-@samp{32bit} hardware multiply support is assumed. @samp{auto} is the
-default setting.
+@samp{32bit} hardware multiply support is assumed. If the MCU name is
+not recognised then no hardware multiply support is assumed.
+@code{auto} is the default setting.
Hardware multiplies are normally performed by calling a library
routine. This saves space in the generated code. When compiling at
linker script and how it assigns the standard sections (.text, .data
etc) to the memory regions.
+@item -msilicon-errata=
+@opindex msilicon-errata
+This option passes on a request to assembler to enable the fixes for
+the named silicon errata.
+
+@item -msilicon-errata-warn=
+@opindex msilicon-errata-warn
+This option passes on a request to the assembler to enable warning
+messages when a silicon errata might need to be applied.
+
@end table
@node NDS32 Options
@item local
Generate GP-relative accesses for small data objects that are not
-external or weak. Also use GP-relative addressing for objects that
+external, weak, or uninitialized common symbols.
+Also use GP-relative addressing for objects that
have been explicitly placed in a small data section via a @code{section}
attribute.
@item global
As for @samp{local}, but also generate GP-relative accesses for
-small data objects that are external or weak. If you use this option,
+small data objects that are external, weak, or common. If you use this option,
you must ensure that all parts of your program (including libraries) are
compiled with the same @option{-G} setting.
Prefer zero-displacement conditional branches for conditional move instruction
patterns. This can result in faster code on the SH4 processor.
+@item -mfdpic
+@opindex fdpic
+Generate code using the FDPIC ABI.
+
@end table
@node Solaris 2 Options
@opindex muser-mode
@opindex mno-user-mode
Do not generate code that can only run in supervisor mode. This is relevant
-only for the @code{casa} instruction emitted for the LEON3 processor. The
-default is @option{-mno-user-mode}.
+only for the @code{casa} instruction emitted for the LEON3 processor. This
+is the default.
@item -mno-faster-structs
@itemx -mfaster-structs
@itemx pentium
Intel Pentium CPU with no MMX support.
-@item lakemount
-Intel Lakemount MCU, based on Intel Pentium CPU.
+@item lakemont
+Intel Lakemont MCU, based on Intel Pentium CPU.
@item pentium-mmx
Intel Pentium MMX CPU, based on Pentium core with MMX instruction set support.
AES, PCL_MUL, CX16, MOVBE, MMX, SSE, SSE2, SSE3, SSE4A, SSSE3, SSE4.1,
SSE4.2, ABM and 64-bit instruction set extensions.
+@item znver1
+AMD Family 17h core based CPUs with x86-64 instruction set support. (This
+supersets BMI, BMI2, F16C, FMA, FSGSBASE, AVX, AVX2, ADCX, RDSEED, MWAITX,
+SHA, CLZERO, AES, PCL_MUL, CX16, MOVBE, MMX, SSE, SSE2, SSE3, SSE4A, SSSE3,
+SSE4.1, SSE4.2, ABM, XSAVEC, XSAVES, CLFLUSHOPT, POPCNT, and 64-bit
+instruction set extensions.
+
@item btver1
CPUs based on AMD Family 14h cores with x86-64 instruction set support. (This
supersets MMX, SSE, SSE2, SSE3, SSSE3, SSE4A, CX16, ABM and 64-bit
@opindex msse
@need 200
@itemx -msse2
+@opindex msse2
@need 200
@itemx -msse3
+@opindex msse3
@need 200
@itemx -mssse3
+@opindex mssse3
@need 200
@itemx -msse4
+@opindex msse4
@need 200
@itemx -msse4a
+@opindex msse4a
@need 200
@itemx -msse4.1
+@opindex msse4.1
@need 200
@itemx -msse4.2
+@opindex msse4.2
@need 200
@itemx -mavx
@opindex mavx
@need 200
@itemx -mavx2
+@opindex mavx2
@need 200
@itemx -mavx512f
+@opindex mavx512f
@need 200
@itemx -mavx512pf
+@opindex mavx512pf
@need 200
@itemx -mavx512er
+@opindex mavx512er
@need 200
@itemx -mavx512cd
+@opindex mavx512cd
+@need 200
+@itemx -mavx512vl
+@opindex mavx512vl
+@need 200
+@itemx -mavx512bw
+@opindex mavx512bw
+@need 200
+@itemx -mavx512dq
+@opindex mavx512dq
+@need 200
+@itemx -mavx512ifma
+@opindex mavx512ifma
+@need 200
+@itemx -mavx512vbmi
+@opindex mavx512vbmi
@need 200
@itemx -msha
@opindex msha
@opindex mfma
@need 200
@itemx -mfma4
+@opindex mfma4
@need 200
@itemx -mno-fma4
+@opindex mno-fma4
@need 200
@itemx -mprefetchwt1
@opindex mprefetchwt1
These switches enable the use of instructions in the MMX, SSE,
SSE2, SSE3, SSSE3, SSE4.1, AVX, AVX2, AVX512F, AVX512PF, AVX512ER, AVX512CD,
SHA, AES, PCLMUL, FSGSBASE, RDRND, F16C, FMA, SSE4A, FMA4, XOP, LWP, ABM,
-BMI, BMI2, FXSR, XSAVE, XSAVEOPT, LZCNT, RTM, MPX, MWAITX or 3DNow!@:
+AVX512VL, AVX512BW, AVX512DQ, AVX512IFMA AVX512VBMI, BMI, BMI2, FXSR,
+XSAVE, XSAVEOPT, LZCNT, RTM, MPX, MWAITX or 3DNow!@:
extended instruction sets. Each has a corresponding @option{-mno-} option
to disable use of these instructions.
projects / thirdparty / gcc.git / blobdiff