gcc/

[thirdparty/gcc.git] / gcc / config / i386 / i386.opt

; Options for the IA-32 and AMD64 ports of the compiler.

; Copyright (C) 2005-2015 Free Software Foundation, Inc.
;
; This file is part of GCC.
;
; GCC is free software; you can redistribute it and/or modify it under
; the terms of the GNU General Public License as published by the Free
; Software Foundation; either version 3, or (at your option) any later
; version.
;
; GCC is distributed in the hope that it will be useful, but WITHOUT ANY
; WARRANTY; without even the implied warranty of MERCHANTABILITY or
; FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
; for more details.
;
; You should have received a copy of the GNU General Public License
; along with GCC; see the file COPYING3.  If not see
; <http://www.gnu.org/licenses/>.

HeaderInclude
config/i386/i386-opts.h

; Bit flags that specify the ISA we are compiling for.
Variable
HOST_WIDE_INT ix86_isa_flags = TARGET_64BIT_DEFAULT | TARGET_SUBTARGET_ISA_DEFAULT

; A mask of ix86_isa_flags that includes bit X if X was set or cleared
; on the command line.
Variable
HOST_WIDE_INT ix86_isa_flags_explicit

TargetVariable
int recip_mask = RECIP_MASK_DEFAULT

Variable
int recip_mask_explicit

TargetSave
int x_recip_mask_explicit

;; Definitions to add to the cl_target_option structure
;; -march= processor
TargetSave
unsigned char arch

;; -mtune= processor
TargetSave
unsigned char tune

;; -march= processor-string
TargetSave
const char *x_ix86_arch_string

;; -mtune= processor-string
TargetSave
const char *x_ix86_tune_string

;; CPU schedule model
TargetSave
unsigned char schedule

;; True if processor has SSE prefetch instruction.
TargetSave
unsigned char prefetch_sse

;; branch cost
TargetSave
unsigned char branch_cost

;; which flags were passed by the user
TargetSave
HOST_WIDE_INT x_ix86_isa_flags_explicit

;; which flags were passed by the user
Variable
int ix86_target_flags_explicit

;; which flags were passed by the user
TargetSave
HOST_WIDE_INT x_ix86_target_flags_explicit

;; whether -mtune was not specified
TargetSave
unsigned char tune_defaulted

;; whether -march was specified
TargetSave
unsigned char arch_specified

;; -mcmodel= model
TargetSave
enum cmodel x_ix86_cmodel

;; -mabi=
TargetSave
enum calling_abi x_ix86_abi

;; -masm=
TargetSave
enum asm_dialect x_ix86_asm_dialect

;; -mbranch-cost=
TargetSave
int x_ix86_branch_cost

;; -mdump-tune-features= 
TargetSave
int x_ix86_dump_tunes

;; -mstackrealign=
TargetSave
int x_ix86_force_align_arg_pointer

;; -mforce-drap= 
TargetSave
int x_ix86_force_drap

;; -mincoming-stack-boundary=
TargetSave
int x_ix86_incoming_stack_boundary_arg

;; -maddress-mode=
TargetSave
enum pmode x_ix86_pmode

;; -mpreferred-stack-boundary= 
TargetSave
int x_ix86_preferred_stack_boundary_arg

;; -mrecip=
TargetSave
const char *x_ix86_recip_name

;; -mregparm=
TargetSave
int x_ix86_regparm

;; -mlarge-data-threshold=
TargetSave
int x_ix86_section_threshold

;; -msse2avx=
TargetSave
int x_ix86_sse2avx

;; -mstack-protector-guard=
TargetSave
enum stack_protector_guard x_ix86_stack_protector_guard

;; -mstringop-strategy=
TargetSave
enum stringop_alg x_ix86_stringop_alg

;; -mtls-dialect=
TargetSave
enum tls_dialect x_ix86_tls_dialect

;; -mtune-ctrl=
TargetSave
const char *x_ix86_tune_ctrl_string

;; -mmemcpy-strategy=
TargetSave
const char *x_ix86_tune_memcpy_strategy

;; -mmemset-strategy=
TargetSave
const char *x_ix86_tune_memset_strategy

;; -mno-default=
TargetSave
int x_ix86_tune_no_default

;; -mveclibabi=
TargetSave
enum ix86_veclibabi x_ix86_veclibabi_type

;; x86 options
m128bit-long-double
Target RejectNegative Report Mask(128BIT_LONG_DOUBLE) Save
sizeof(long double) is 16

m80387
Target Report Mask(80387) Save
Use hardware fp

m96bit-long-double
Target RejectNegative Report InverseMask(128BIT_LONG_DOUBLE) Save
sizeof(long double) is 12

mlong-double-80
Target Report RejectNegative Negative(mlong-double-64) InverseMask(LONG_DOUBLE_64) Save
Use 80-bit long double

mlong-double-64
Target Report RejectNegative Negative(mlong-double-128) Mask(LONG_DOUBLE_64) InverseMask(LONG_DOUBLE_128) Save
Use 64-bit long double

mlong-double-128
Target Report RejectNegative Negative(mlong-double-80) Mask(LONG_DOUBLE_128) InverseMask(LONG_DOUBLE_64) Save
Use 128-bit long double

maccumulate-outgoing-args
Target Report Mask(ACCUMULATE_OUTGOING_ARGS) Save
Reserve space for outgoing arguments in the function prologue

malign-double
Target Report Mask(ALIGN_DOUBLE) Save
Align some doubles on dword boundary

malign-functions=
Target RejectNegative Joined UInteger
Function starts are aligned to this power of 2

malign-jumps=
Target RejectNegative Joined UInteger
Jump targets are aligned to this power of 2

malign-loops=
Target RejectNegative Joined UInteger
Loop code aligned to this power of 2

malign-stringops
Target RejectNegative Report InverseMask(NO_ALIGN_STRINGOPS, ALIGN_STRINGOPS) Save
Align destination of the string operations

malign-data=
Target RejectNegative Joined Var(ix86_align_data_type) Enum(ix86_align_data) Init(ix86_align_data_type_compat)
Use the given data alignment

Enum
Name(ix86_align_data) Type(enum ix86_align_data)
Known data alignment choices (for use with the -malign-data= option):

EnumValue
Enum(ix86_align_data) String(compat) Value(ix86_align_data_type_compat)

EnumValue
Enum(ix86_align_data) String(abi) Value(ix86_align_data_type_abi)

EnumValue
Enum(ix86_align_data) String(cacheline) Value(ix86_align_data_type_cacheline)

march=
Target RejectNegative Joined Var(ix86_arch_string)
Generate code for given CPU

masm=
Target RejectNegative Joined Enum(asm_dialect) Var(ix86_asm_dialect) Init(ASM_ATT)
Use given assembler dialect

Enum
Name(asm_dialect) Type(enum asm_dialect)
Known assembler dialects (for use with the -masm-dialect= option):

EnumValue
Enum(asm_dialect) String(intel) Value(ASM_INTEL)

EnumValue
Enum(asm_dialect) String(att) Value(ASM_ATT)

mbranch-cost=
Target RejectNegative Joined UInteger Var(ix86_branch_cost)
Branches are this expensive (1-5, arbitrary units)

mlarge-data-threshold=
Target RejectNegative Joined UInteger Var(ix86_section_threshold) Init(DEFAULT_LARGE_SECTION_THRESHOLD)
Data greater than given threshold will go into .ldata section in x86-64 medium model

mcmodel=
Target RejectNegative Joined Enum(cmodel) Var(ix86_cmodel) Init(CM_32)
Use given x86-64 code model

Enum
Name(cmodel) Type(enum cmodel)
Known code models (for use with the -mcmodel= option):

EnumValue
Enum(cmodel) String(small) Value(CM_SMALL)

EnumValue
Enum(cmodel) String(medium) Value(CM_MEDIUM)

EnumValue
Enum(cmodel) String(large) Value(CM_LARGE)

EnumValue
Enum(cmodel) String(32) Value(CM_32)

EnumValue
Enum(cmodel) String(kernel) Value(CM_KERNEL)

maddress-mode=
Target RejectNegative Joined Enum(pmode) Var(ix86_pmode) Init(PMODE_SI)
Use given address mode

Enum
Name(pmode) Type(enum pmode)
Known address mode (for use with the -maddress-mode= option):

EnumValue
Enum(pmode) String(short) Value(PMODE_SI)

EnumValue
Enum(pmode) String(long) Value(PMODE_DI)

mcpu=
Target RejectNegative Joined Undocumented Alias(mtune=) Warn(%<-mcpu=%> is deprecated; use %<-mtune=%> or %<-march=%> instead)

mfancy-math-387
Target RejectNegative Report InverseMask(NO_FANCY_MATH_387, USE_FANCY_MATH_387) Save
Generate sin, cos, sqrt for FPU

mforce-drap
Target Report Var(ix86_force_drap)
Always use Dynamic Realigned Argument Pointer (DRAP) to realign stack

mfp-ret-in-387
Target Report Mask(FLOAT_RETURNS) Save
Return values of functions in FPU registers

mfpmath=
Target RejectNegative Joined Var(ix86_fpmath) Enum(fpmath_unit) Init(FPMATH_387) Save
Generate floating point mathematics using given instruction set

Enum
Name(fpmath_unit) Type(enum fpmath_unit)
Valid arguments to -mfpmath=:

EnumValue
Enum(fpmath_unit) String(387) Value(FPMATH_387)

EnumValue
Enum(fpmath_unit) String(sse) Value(FPMATH_SSE)

EnumValue
Enum(fpmath_unit) String(387,sse) Value({(enum fpmath_unit) (FPMATH_SSE | FPMATH_387)})

EnumValue
Enum(fpmath_unit) String(387+sse) Value({(enum fpmath_unit) (FPMATH_SSE | FPMATH_387)})

EnumValue
Enum(fpmath_unit) String(sse,387) Value({(enum fpmath_unit) (FPMATH_SSE | FPMATH_387)})

EnumValue
Enum(fpmath_unit) String(sse+387) Value({(enum fpmath_unit) (FPMATH_SSE | FPMATH_387)})

EnumValue
Enum(fpmath_unit) String(both) Value({(enum fpmath_unit) (FPMATH_SSE | FPMATH_387)})

mhard-float
Target RejectNegative Mask(80387) Save
Use hardware fp

mieee-fp
Target Report Mask(IEEE_FP) Save
Use IEEE math for fp comparisons

minline-all-stringops
Target Report Mask(INLINE_ALL_STRINGOPS) Save
Inline all known string operations

minline-stringops-dynamically
Target Report Mask(INLINE_STRINGOPS_DYNAMICALLY) Save
Inline memset/memcpy string operations, but perform inline version only for small blocks

mintel-syntax
Target Undocumented Alias(masm=, intel, att) Warn(%<-mintel-syntax%> and %<-mno-intel-syntax%> are deprecated; use %<-masm=intel%> and %<-masm=att%> instead)
;; Deprecated

mms-bitfields
Target Report Mask(MS_BITFIELD_LAYOUT) Save
Use native (MS) bitfield layout

mno-align-stringops
Target RejectNegative Report Mask(NO_ALIGN_STRINGOPS) Undocumented Save

mno-fancy-math-387
Target RejectNegative Report Mask(NO_FANCY_MATH_387) Undocumented Save

mno-push-args
Target RejectNegative Report Mask(NO_PUSH_ARGS) Undocumented Save

mno-red-zone
Target RejectNegative Report Mask(NO_RED_ZONE) Undocumented Save

momit-leaf-frame-pointer
Target Report Mask(OMIT_LEAF_FRAME_POINTER) Save
Omit the frame pointer in leaf functions

mpc32
Target RejectNegative Report
Set 80387 floating-point precision to 32-bit

mpc64
Target RejectNegative Report
Set 80387 floating-point precision to 64-bit

mpc80
Target RejectNegative Report
Set 80387 floating-point precision to 80-bit

mpreferred-stack-boundary=
Target RejectNegative Joined UInteger Var(ix86_preferred_stack_boundary_arg)
Attempt to keep stack aligned to this power of 2

mincoming-stack-boundary=
Target RejectNegative Joined UInteger Var(ix86_incoming_stack_boundary_arg)
Assume incoming stack aligned to this power of 2

mpush-args
Target Report InverseMask(NO_PUSH_ARGS, PUSH_ARGS) Save
Use push instructions to save outgoing arguments

mred-zone
Target RejectNegative Report InverseMask(NO_RED_ZONE, RED_ZONE) Save
Use red-zone in the x86-64 code

mregparm=
Target RejectNegative Joined UInteger Var(ix86_regparm)
Number of registers used to pass integer arguments

mrtd
Target Report Mask(RTD) Save
Alternate calling convention

msoft-float
Target InverseMask(80387) Save
Do not use hardware fp

msseregparm
Target RejectNegative Mask(SSEREGPARM) Save
Use SSE register passing conventions for SF and DF mode

mstackrealign
Target Report Var(ix86_force_align_arg_pointer) Init(-1)
Realign stack in prologue

mstack-arg-probe
Target Report Mask(STACK_PROBE) Save
Enable stack probing

mmemcpy-strategy=
Target RejectNegative Joined Var(ix86_tune_memcpy_strategy)
Specify memcpy expansion strategy when expected size is known

mmemset-strategy=
Target RejectNegative Joined Var(ix86_tune_memset_strategy)
Specify memset expansion strategy when expected size is known

mstringop-strategy=
Target RejectNegative Joined Enum(stringop_alg) Var(ix86_stringop_alg) Init(no_stringop)
Chose strategy to generate stringop using

Enum
Name(stringop_alg) Type(enum stringop_alg)
Valid arguments to -mstringop-strategy=:

EnumValue
Enum(stringop_alg) String(rep_byte) Value(rep_prefix_1_byte)

EnumValue
Enum(stringop_alg) String(libcall) Value(libcall)

EnumValue
Enum(stringop_alg) String(rep_4byte) Value(rep_prefix_4_byte)

EnumValue
Enum(stringop_alg) String(rep_8byte) Value(rep_prefix_8_byte)

EnumValue
Enum(stringop_alg) String(byte_loop) Value(loop_1_byte)

EnumValue
Enum(stringop_alg) String(loop) Value(loop)

EnumValue
Enum(stringop_alg) String(unrolled_loop) Value(unrolled_loop)

EnumValue
Enum(stringop_alg) String(vector_loop) Value(vector_loop)

mtls-dialect=
Target RejectNegative Joined Var(ix86_tls_dialect) Enum(tls_dialect) Init(TLS_DIALECT_GNU)
Use given thread-local storage dialect

Enum
Name(tls_dialect) Type(enum tls_dialect)
Known TLS dialects (for use with the -mtls-dialect= option):

EnumValue
Enum(tls_dialect) String(gnu) Value(TLS_DIALECT_GNU)

EnumValue
Enum(tls_dialect) String(gnu2) Value(TLS_DIALECT_GNU2)

mtls-direct-seg-refs
Target Report Mask(TLS_DIRECT_SEG_REFS)
Use direct references against %gs when accessing tls data

mtune=
Target RejectNegative Joined Var(ix86_tune_string)
Schedule code for given CPU

mtune-ctrl=
Target RejectNegative Joined Var(ix86_tune_ctrl_string)
Fine grain control of tune features

mno-default
Target RejectNegative Var(ix86_tune_no_default) Init(0)
Clear all tune features

mdump-tune-features
Target RejectNegative Var(ix86_dump_tunes) Init(0)

mabi=
Target RejectNegative Joined Var(ix86_abi) Enum(calling_abi) Init(SYSV_ABI)
Generate code that conforms to the given ABI

Enum
Name(calling_abi) Type(enum calling_abi)
Known ABIs (for use with the -mabi= option):

EnumValue
Enum(calling_abi) String(sysv) Value(SYSV_ABI)

EnumValue
Enum(calling_abi) String(ms) Value(MS_ABI)

mveclibabi=
Target RejectNegative Joined Var(ix86_veclibabi_type) Enum(ix86_veclibabi) Init(ix86_veclibabi_type_none)
Vector library ABI to use

Enum
Name(ix86_veclibabi) Type(enum ix86_veclibabi)
Known vectorization library ABIs (for use with the -mveclibabi= option):

EnumValue
Enum(ix86_veclibabi) String(svml) Value(ix86_veclibabi_type_svml)

EnumValue
Enum(ix86_veclibabi) String(acml) Value(ix86_veclibabi_type_acml)

mvect8-ret-in-mem
Target Report Mask(VECT8_RETURNS) Save
Return 8-byte vectors in memory

mrecip
Target Report Mask(RECIP) Save
Generate reciprocals instead of divss and sqrtss.

mrecip=
Target Report RejectNegative Joined Var(ix86_recip_name)
Control generation of reciprocal estimates.

mcld
Target Report Mask(CLD) Save
Generate cld instruction in the function prologue.

mvzeroupper
Target Report Mask(VZEROUPPER) Save
Generate vzeroupper instruction before a transfer of control flow out of
the function.

mdispatch-scheduler
Target RejectNegative Var(flag_dispatch_scheduler)
Do dispatch scheduling if processor is bdver1 or bdver2 or bdver3 or bdver4 and Haifa scheduling
is selected.

mprefer-avx128
Target Report Mask(PREFER_AVX128) SAVE
Use 128-bit AVX instructions instead of 256-bit AVX instructions in the auto-vectorizer.

;; ISA support

m32
Target RejectNegative Negative(m64) Report InverseMask(ISA_64BIT) Var(ix86_isa_flags) Save
Generate 32bit i386 code

m64
Target RejectNegative Negative(mx32) Report Mask(ABI_64) Var(ix86_isa_flags) Save
Generate 64bit x86-64 code

mx32
Target RejectNegative Negative(m16) Report Mask(ABI_X32) Var(ix86_isa_flags) Save
Generate 32bit x86-64 code

m16
Target RejectNegative Negative(m32) Report Mask(CODE16) InverseMask(ISA_64BIT) Var(ix86_isa_flags) Save
Generate 16bit i386 code

mmmx
Target Report Mask(ISA_MMX) Var(ix86_isa_flags) Save
Support MMX built-in functions

m3dnow
Target Report Mask(ISA_3DNOW) Var(ix86_isa_flags) Save
Support 3DNow! built-in functions

m3dnowa
Target Undocumented Mask(ISA_3DNOW_A) Var(ix86_isa_flags) Save
Support Athlon 3Dnow! built-in functions

msse
Target Report Mask(ISA_SSE) Var(ix86_isa_flags) Save
Support MMX and SSE built-in functions and code generation

msse2
Target Report Mask(ISA_SSE2) Var(ix86_isa_flags) Save
Support MMX, SSE and SSE2 built-in functions and code generation

msse3
Target Report Mask(ISA_SSE3) Var(ix86_isa_flags) Save
Support MMX, SSE, SSE2 and SSE3 built-in functions and code generation

mssse3
Target Report Mask(ISA_SSSE3) Var(ix86_isa_flags) Save
Support MMX, SSE, SSE2, SSE3 and SSSE3 built-in functions and code generation

msse4.1
Target Report Mask(ISA_SSE4_1) Var(ix86_isa_flags) Save
Support MMX, SSE, SSE2, SSE3, SSSE3 and SSE4.1 built-in functions and code generation

msse4.2
Target Report Mask(ISA_SSE4_2) Var(ix86_isa_flags) Save
Support MMX, SSE, SSE2, SSE3, SSSE3, SSE4.1 and SSE4.2 built-in functions and code generation

msse4
Target RejectNegative Report Mask(ISA_SSE4_2) Var(ix86_isa_flags) Save
Support MMX, SSE, SSE2, SSE3, SSSE3, SSE4.1 and SSE4.2 built-in functions and code generation

mno-sse4
Target RejectNegative Report InverseMask(ISA_SSE4_1) Var(ix86_isa_flags) Save
Do not support SSE4.1 and SSE4.2 built-in functions and code generation

msse5
Target Undocumented Alias(mavx) Warn(%<-msse5%> was removed)
;; Deprecated

mavx
Target Report Mask(ISA_AVX) Var(ix86_isa_flags) Save
Support MMX, SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2 and AVX built-in functions and code generation

mavx2
Target Report Mask(ISA_AVX2) Var(ix86_isa_flags) Save
Support MMX, SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2, AVX and AVX2 built-in functions and code generation

mavx512f
Target Report Mask(ISA_AVX512F) Var(ix86_isa_flags) Save
Support MMX, SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2, AVX, AVX2 and AVX512F built-in functions and code generation

mavx512pf
Target Report Mask(ISA_AVX512PF) Var(ix86_isa_flags) Save
Support MMX, SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2, AVX, AVX2 and AVX512F and AVX512PF built-in functions and code generation

mavx512er
Target Report Mask(ISA_AVX512ER) Var(ix86_isa_flags) Save
Support MMX, SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2, AVX, AVX2 and AVX512F and AVX512ER built-in functions and code generation

mavx512cd
Target Report Mask(ISA_AVX512CD) Var(ix86_isa_flags) Save
Support MMX, SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2, AVX, AVX2 and AVX512F and AVX512CD built-in functions and code generation

mavx512dq
Target Report Mask(ISA_AVX512DQ) Var(ix86_isa_flags) Save
Support MMX, SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2, AVX, AVX2 and AVX512F and AVX512DQ built-in functions and code generation

mavx512bw
Target Report Mask(ISA_AVX512BW) Var(ix86_isa_flags) Save
Support MMX, SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2, AVX, AVX2 and AVX512F and AVX512BW built-in functions and code generation

mavx512vl
Target Report Mask(ISA_AVX512VL) Var(ix86_isa_flags) Save
Support MMX, SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2, AVX, AVX2 and AVX512F and AVX512VL built-in functions and code generation

mavx512ifma
Target Report Mask(ISA_AVX512IFMA) Var(ix86_isa_flags) Save
Support MMX, SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2, AVX, AVX2 and AVX512F and AVX512IFMA built-in functions and code generation

mavx512vbmi
Target Report Mask(ISA_AVX512VBMI) Var(ix86_isa_flags) Save
Support MMX, SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2, AVX, AVX2 and AVX512F and AVX512VBMI built-in functions and code generation

mfma
Target Report Mask(ISA_FMA) Var(ix86_isa_flags) Save
Support MMX, SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2, AVX and FMA built-in functions and code generation

msse4a
Target Report Mask(ISA_SSE4A) Var(ix86_isa_flags) Save
Support MMX, SSE, SSE2, SSE3 and SSE4A built-in functions and code generation

mfma4
Target Report Mask(ISA_FMA4) Var(ix86_isa_flags) Save
Support FMA4 built-in functions and code generation 

mxop
Target Report Mask(ISA_XOP) Var(ix86_isa_flags) Save
Support XOP built-in functions and code generation 

mlwp
Target Report Mask(ISA_LWP) Var(ix86_isa_flags) Save
Support LWP built-in functions and code generation 

mabm
Target Report Mask(ISA_ABM) Var(ix86_isa_flags) Save
Support code generation of Advanced Bit Manipulation (ABM) instructions.

mpopcnt
Target Report Mask(ISA_POPCNT) Var(ix86_isa_flags) Save
Support code generation of popcnt instruction.

mbmi
Target Report Mask(ISA_BMI) Var(ix86_isa_flags) Save
Support BMI built-in functions and code generation

mbmi2
Target Report Mask(ISA_BMI2) Var(ix86_isa_flags) Save
Support BMI2 built-in functions and code generation

mlzcnt
Target Report Mask(ISA_LZCNT) Var(ix86_isa_flags) Save
Support LZCNT built-in function and code generation

mhle
Target Report Mask(ISA_HLE) Var(ix86_isa_flags) Save
Support Hardware Lock Elision prefixes

mrdseed
Target Report Mask(ISA_RDSEED) Var(ix86_isa_flags) Save
Support RDSEED instruction

mprfchw
Target Report Mask(ISA_PRFCHW) Var(ix86_isa_flags) Save
Support PREFETCHW instruction

madx
Target Report Mask(ISA_ADX) Var(ix86_isa_flags) Save
Support flag-preserving add-carry instructions

mclflushopt
Target Report Mask(ISA_CLFLUSHOPT) Var(ix86_isa_flags) Save
Support CLFLUSHOPT instructions

mclwb
Target Report Mask(ISA_CLWB) Var(ix86_isa_flags) Save
Support CLWB instruction

mpcommit
Target Report Mask(ISA_PCOMMIT) Var(ix86_isa_flags) Save
Support PCOMMIT instruction

mfxsr
Target Report Mask(ISA_FXSR) Var(ix86_isa_flags) Save
Support FXSAVE and FXRSTOR instructions

mxsave
Target Report Mask(ISA_XSAVE) Var(ix86_isa_flags) Save
Support XSAVE and XRSTOR instructions

mxsaveopt
Target Report Mask(ISA_XSAVEOPT) Var(ix86_isa_flags) Save
Support XSAVEOPT instruction

mxsavec
Target Report Mask(ISA_XSAVEC) Var(ix86_isa_flags) Save
Support XSAVEC instructions

mxsaves
Target Report Mask(ISA_XSAVES) Var(ix86_isa_flags) Save
Support XSAVES and XRSTORS instructions

mtbm
Target Report Mask(ISA_TBM) Var(ix86_isa_flags) Save
Support TBM built-in functions and code generation

mcx16
Target Report Mask(ISA_CX16) Var(ix86_isa_flags) Save
Support code generation of cmpxchg16b instruction.

msahf
Target Report Mask(ISA_SAHF) Var(ix86_isa_flags) Save
Support code generation of sahf instruction in 64bit x86-64 code.

mmovbe
Target Report Mask(ISA_MOVBE) Var(ix86_isa_flags) Save
Support code generation of movbe instruction.

mcrc32
Target Report Mask(ISA_CRC32) Var(ix86_isa_flags) Save
Support code generation of crc32 instruction.

maes
Target Report Mask(ISA_AES) Var(ix86_isa_flags) Save
Support AES built-in functions and code generation

msha
Target Report Mask(ISA_SHA) Var(ix86_isa_flags) Save
Support SHA1 and SHA256 built-in functions and code generation

mpclmul
Target Report Mask(ISA_PCLMUL) Var(ix86_isa_flags) Save
Support PCLMUL built-in functions and code generation

msse2avx
Target Report Var(ix86_sse2avx)
Encode SSE instructions with VEX prefix

mfsgsbase
Target Report Mask(ISA_FSGSBASE) Var(ix86_isa_flags) Save
Support FSGSBASE built-in functions and code generation

mrdrnd
Target Report Mask(ISA_RDRND) Var(ix86_isa_flags) Save
Support RDRND built-in functions and code generation

mf16c
Target Report Mask(ISA_F16C) Var(ix86_isa_flags) Save
Support F16C built-in functions and code generation

mprefetchwt1
Target Report Mask(ISA_PREFETCHWT1) Var(ix86_isa_flags) Save
Support PREFETCHWT1 built-in functions and code generation

mfentry
Target Report Var(flag_fentry) Init(-1)
Emit profiling counter call at function entry before prologue.

mrecord-mcount
Target Report Var(flag_record_mcount) Init(0)
Generate __mcount_loc section with all mcount or __fentry__ calls.

mnop-mcount
Target Report Var(flag_nop_mcount) Init(0)
Generate mcount/__fentry__ calls as nops. To activate they need to be
patched in.

mskip-rax-setup
Target Report Var(flag_skip_rax_setup) Init(0)
Skip setting up RAX register when passing variable arguments.

m8bit-idiv
Target Report Mask(USE_8BIT_IDIV) Save
Expand 32bit/64bit integer divide into 8bit unsigned integer divide with run-time check

mavx256-split-unaligned-load
Target Report Mask(AVX256_SPLIT_UNALIGNED_LOAD) Save
Split 32-byte AVX unaligned load

mavx256-split-unaligned-store
Target Report Mask(AVX256_SPLIT_UNALIGNED_STORE) Save
Split 32-byte AVX unaligned store

mrtm
Target Report Mask(ISA_RTM) Var(ix86_isa_flags) Save
Support RTM built-in functions and code generation

mmpx
Target Report Mask(ISA_MPX) Var(ix86_isa_flags) Save
Support MPX code generation

mmwaitx
Target Report Mask(ISA_MWAITX) Var(ix86_isa_flags) Save
Support MWAITX and MONITORX built-in functions and code generation

mstack-protector-guard=
Target RejectNegative Joined Enum(stack_protector_guard) Var(ix86_stack_protector_guard) Init(SSP_TLS)
Use given stack-protector guard

Enum
Name(stack_protector_guard) Type(enum stack_protector_guard)
Known stack protector guard (for use with the -mstack-protector-guard= option):

EnumValue
Enum(stack_protector_guard) String(tls) Value(SSP_TLS)

EnumValue
Enum(stack_protector_guard) String(global) Value(SSP_GLOBAL)