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| author | Ulrich Drepper <drepper@gmail.com> | 2011-10-24 22:11:21 -0400 |
|---|---|---|
| committer | Ulrich Drepper <drepper@gmail.com> | 2011-10-24 22:11:21 -0400 |
| commit | 202c9deb15ee43bcbe70b36fa9bae050b8633c27 (patch) | |
| tree | da6f340b0a0475b22c0ec7664f2dfea47aaad153 | |
| parent | 485683c35f020bd8b926e9673adb9b748380e8ce (diff) | |
| download | glibc-202c9deb15ee43bcbe70b36fa9bae050b8633c27.tar.gz glibc-202c9deb15ee43bcbe70b36fa9bae050b8633c27.tar.xz glibc-202c9deb15ee43bcbe70b36fa9bae050b8633c27.zip | |
Better DLA_FMS
It's better to use __builtin_fma if it works. Use it for gcc 4.6 and higher. Move the x86-64 dla.h to the correct place.
| -rw-r--r-- | ChangeLog | 6 | ||||
| -rw-r--r-- | sysdeps/x86_64/fpu/dla.h (renamed from sysdeps/x86_64/dla.h) | 9 |
2 files changed, 12 insertions, 3 deletions
diff --git a/ChangeLog b/ChangeLog index 108d9a96c3..992ad4cb2a 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,7 +1,9 @@ 2011-10-24 Ulrich Drepper <drepper@gmail.com> - * sysdeps/x86_64/dla.h (DLA_FMS): Some compilers fail to inline - __builtin_fma in some situations. Have to use an asm. + * sysdeps/x86_64/dla.h: Move to ... + * sysdeps/x86_64/fpu/dla.h: ...here. + (DLA_FMS): Some compilers fail to inline __builtin_fma in some + situations. Use __builtin_fma only for gcc 4.6 and up. * config.make.in: Add have-mfma4 entry. * configure.in: Substitute libc_cv_cc_fma4. diff --git a/sysdeps/x86_64/dla.h b/sysdeps/x86_64/fpu/dla.h index 6fe8f740f3..fa2d52bbf0 100644 --- a/sysdeps/x86_64/dla.h +++ b/sysdeps/x86_64/fpu/dla.h @@ -1,10 +1,17 @@ +#include <features.h> + #ifdef __FMA4__ -# define DLA_FMS(x,y,z) \ +# if __GNUC_PREREQ (4, 6) +# define DLA_FMS(x,y,z) \ + __builtin_fma (x, y, -(z)) +# else +# define DLA_FMS(x,y,z) \ ({ double __z; \ asm ("vfmsubsd %3, %2, %1, %0" \ : "=x" (__z) \ : "x" ((double) (x)), "xm" ((double) (y)) , "x" ((double) (z))); \ __z; }) +# endif #endif #include "sysdeps/ieee754/dbl-64/dla.h" |