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| author | liuhongt <hongtao.liu@intel.com> | 2022-12-12 15:43:58 +0800 |
|---|---|---|
| committer | liuhongt <hongtao.liu@intel.com> | 2022-12-26 09:11:44 +0800 |
| commit | e54375d85d4aa5889869c2672158083b2106b623 (patch) | |
| tree | 5570081bb54818c753f2f39d2fd1c5ebc230c8be /gcc | |
| parent | bc38aee755ddd50496f9a1d517a9cdd86301967d (diff) | |
| download | gcc-e54375d85d4aa5889869c2672158083b2106b623.zip gcc-e54375d85d4aa5889869c2672158083b2106b623.tar.gz gcc-e54375d85d4aa5889869c2672158083b2106b623.tar.bz2 | |
x86: Add a new option -mdaz-ftz to enable FTZ and DAZ flags in MXCSR.
if (mdaz-ftz)
link crtfastmath.o
else if ((Ofast || ffast-math || funsafe-math-optimizations)
&& !shared && !mno-daz-ftz)
link crtfastmath.o
else
Don't link crtfastmath.o
gcc/ChangeLog:
PR target/55522
PR target/36821
* config/i386/gnu-user-common.h (GNU_USER_TARGET_MATHFILE_SPEC):
Link crtfastmath.o whenever -mdaz-ftz is specified. Don't link
crtfastmath.o when -share or -mno-daz-ftz is specified.
* config/i386/i386.opt (mdaz-ftz): New option.
* doc/invoke.texi (x86 options): Document mftz-daz.
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/config/i386/gnu-user-common.h | 2 | ||||
| -rw-r--r-- | gcc/config/i386/i386.opt | 4 | ||||
| -rw-r--r-- | gcc/doc/invoke.texi | 12 |
3 files changed, 16 insertions, 2 deletions
diff --git a/gcc/config/i386/gnu-user-common.h b/gcc/config/i386/gnu-user-common.h index 9910cd6..f910524 100644 --- a/gcc/config/i386/gnu-user-common.h +++ b/gcc/config/i386/gnu-user-common.h @@ -47,7 +47,7 @@ along with GCC; see the file COPYING3. If not see /* Similar to standard GNU userspace, but adding -ffast-math support. */ #define GNU_USER_TARGET_MATHFILE_SPEC \ - "%{Ofast|ffast-math|funsafe-math-optimizations:%{!shared:crtfastmath.o%s}} \ + "%{mdaz-ftz:crtfastmath.o%s;Ofast|ffast-math|funsafe-math-optimizations:%{!shared:%{!mno-daz-ftz:crtfastmath.o%s}}} \ %{mpc32:crtprec32.o%s} \ %{mpc64:crtprec64.o%s} \ %{mpc80:crtprec80.o%s}" diff --git a/gcc/config/i386/i386.opt b/gcc/config/i386/i386.opt index fb4e57a..0b7df42 100644 --- a/gcc/config/i386/i386.opt +++ b/gcc/config/i386/i386.opt @@ -420,6 +420,10 @@ mpc80 Target RejectNegative Set 80387 floating-point precision to 80-bit. +mdaz-ftz +Target +Set the FTZ and DAZ Flags. + mpreferred-stack-boundary= Target RejectNegative Joined UInteger Var(ix86_preferred_stack_boundary_arg) Attempt to keep stack aligned to this power of 2. diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index da9ad10..0bbf709 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -1433,7 +1433,7 @@ See RS/6000 and PowerPC Options. -m96bit-long-double -mlong-double-64 -mlong-double-80 -mlong-double-128 @gol -mregparm=@var{num} -msseregparm @gol -mveclibabi=@var{type} -mvect8-ret-in-mem @gol --mpc32 -mpc64 -mpc80 -mstackrealign @gol +-mpc32 -mpc64 -mpc80 -mdaz-ftz -mstackrealign @gol -momit-leaf-frame-pointer -mno-red-zone -mno-tls-direct-seg-refs @gol -mcmodel=@var{code-model} -mabi=@var{name} -maddress-mode=@var{mode} @gol -m32 -m64 -mx32 -m16 -miamcu -mlarge-data-threshold=@var{num} @gol @@ -32793,6 +32793,16 @@ are enabled by default; routines in such libraries could suffer significant loss of accuracy, typically through so-called ``catastrophic cancellation'', when this option is used to set the precision to less than extended precision. +@item -mdaz-ftz +@opindex mdaz-ftz + +The flush-to-zero (FTZ) and denormals-are-zero (DAZ) flags in the MXCSR register +are used to control floating-point calculations.SSE and AVX instructions +including scalar and vector instructions could benefit from enabling the FTZ +and DAZ flags when @option{-mdaz-ftz} is specified. Don't set FTZ/DAZ flags +when @option{-mno-daz-ftz} or @option{-shared} is specified, @option{-mdaz-ftz} +will set FTZ/DAZ flags even with @option{-shared}. + @item -mstackrealign @opindex mstackrealign Realign the stack at entry. On the x86, the @option{-mstackrealign} |