Hello!
Attached patch introduces __builtin_ia32_fxsave to crtfastmath.c. In
addition, it clears only fxsave.mxcsr_mask, as we will look at this
field only. Also, we don't have to execute additional stmxcsr, since
fxsave also saves this register.
2012-10-26 Uros Bizjak <ubiz...@gmail.com>
* config/i386/crtfastmath.c (set_fast_math): Use __builtin_ia32_fxsave.
Clear only fxsave.mxcsr_mask. Use saved mxcsr from fxsave structure
when appropriate. Correct structure element types.
* config/i386/t-crtfm (crtfastmath.o): Compile with -mfxsr, remove
-minline-all-stringops from compile flags.
Patch was bootstrapped and regression tested on x86_64-pc-linux-gnu {,-m32}.
Committed to mainline SVN.
Uros.
Index: config/i386/crtfastmath.c
===================================================================
--- config/i386/crtfastmath.c (revision 192841)
+++ config/i386/crtfastmath.c (working copy)
@@ -91,36 +91,41 @@ set_fast_math (void)
return;
#endif /* __sun__ && __svr4__ */
- mxcsr = __builtin_ia32_stmxcsr () | MXCSR_FTZ;
-
if (edx & bit_FXSAVE)
{
/* Check if DAZ is available. */
struct
{
- unsigned short int cwd;
- unsigned short int swd;
- unsigned short int twd;
- unsigned short int fop;
- long int fip;
- long int fcs;
- long int foo;
- long int fos;
- long int mxcsr;
- long int mxcsr_mask;
- long int st_space[32];
- long int xmm_space[32];
- long int padding[56];
+ unsigned short cwd;
+ unsigned short swd;
+ unsigned short twd;
+ unsigned short fop;
+ unsigned int fip;
+ unsigned int fcs;
+ unsigned int foo;
+ unsigned int fos;
+ unsigned int mxcsr;
+ unsigned int mxcsr_mask;
+ unsigned int st_space[32];
+ unsigned int xmm_space[32];
+ unsigned int padding[56];
} __attribute__ ((aligned (16))) fxsave;
- __builtin_memset (&fxsave, 0, sizeof (fxsave));
+ /* This is necessary since some implementations of FXSAVE
+ do not modify reserved areas within the image. */
+ fxsave.mxcsr_mask = 0;
- asm volatile ("fxsave %0" : "=m" (fxsave) : "m" (fxsave));
+ __builtin_ia32_fxsave (&fxsave);
+ mxcsr = fxsave.mxcsr;
+
if (fxsave.mxcsr_mask & MXCSR_DAZ)
mxcsr |= MXCSR_DAZ;
}
+ else
+ mxcsr = __builtin_ia32_stmxcsr ();
+ mxcsr |= MXCSR_FTZ;
__builtin_ia32_ldmxcsr (mxcsr);
}
#else
Index: config/i386/t-crtfm
===================================================================
--- config/i386/t-crtfm (revision 192841)
+++ config/i386/t-crtfm (working copy)
@@ -1,4 +1,4 @@
# This is an endfile, Use -minline-all-stringops to ensure
# that __builtin_memset doesn't refer to the lib function memset().
crtfastmath.o: $(srcdir)/config/i386/crtfastmath.c
- $(gcc_compile) -msse -minline-all-stringops -c $<
+ $(gcc_compile) -mfxsr -msse -c $<
