From: Ulrich Drepper <drepper@gmail.com>
Date: Tue, 25 Oct 2011 02:11:21 +0000 (-0400)
Subject: Better DLA_FMS
X-Git-Tag: glibc-2.15~161
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=202c9deb15ee43bcbe70b36fa9bae050b8633c27;p=thirdparty%2Fglibc.git

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.
---

diff --git a/ChangeLog b/ChangeLog
index 108d9a96c38..992ad4cb2ad 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
similarity index 63%
rename from sysdeps/x86_64/dla.h
rename to sysdeps/x86_64/fpu/dla.h
index 6fe8f740f35..fa2d52bbf0c 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"