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authorJoseph Myers <joseph@codesourcery.com>2017-09-20 16:54:05 +0000
committerJoseph Myers <joseph@codesourcery.com>2017-09-20 16:54:05 +0000
commitae8372d7e4c44f6839aa3d851d4d0cb486b81cd5 (patch)
tree83340587a4086402e9f1686c278aa1a264ef77e7 /NEWS
parenta856d4d4a8a56eaefdddb58884bfa2bfe922ee4c (diff)
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Add SSE4.1 trunc, truncf (bug 20142).
This patch adds SSE4.1 versions of trunc and truncf, using the roundsd
/ roundss instructions, similar to the versions of ceil, floor, rint
and nearbyint functions we already have.  In my testing with the glibc
benchtests these are about 30% faster than the C versions for double,
20% faster for float.

Tested for x86_64.

	[BZ #20142]
	* sysdeps/x86_64/fpu/multiarch/Makefile (libm-sysdep_routines):
	Add s_trunc-c, s_truncf-c, s_trunc-sse4_1 and s_truncf-sse4_1.
	* sysdeps/x86_64/fpu/multiarch/s_trunc-c.c: New file.
	* sysdeps/x86_64/fpu/multiarch/s_trunc-sse4_1.S: Likewise.
	* sysdeps/x86_64/fpu/multiarch/s_trunc.c: Likewise.
	* sysdeps/x86_64/fpu/multiarch/s_truncf-c.c: Likewise.
	* sysdeps/x86_64/fpu/multiarch/s_truncf-sse4_1.S: Likewise.
	* sysdeps/x86_64/fpu/multiarch/s_truncf.c: Likewise.
Diffstat (limited to 'NEWS')
-rw-r--r--NEWS2
1 files changed, 2 insertions, 0 deletions
diff --git a/NEWS b/NEWS
index dd381f8930..a3aa94cb3b 100644
--- a/NEWS
+++ b/NEWS
@@ -12,6 +12,8 @@ Major new features:
 * Optimized x86-64 asin, atan2, exp, expf, log, pow, atan, sin and tan
   with FMA, contributed by Arjan van de Ven and H.J. Lu from Intel.
 
+* Optimized x86-64 trunc and truncf for processors with SSE4.1.
+
 * In order to support faster and safer process termination the malloc API
   family of functions will no longer print a failure address and stack
   backtrace after detecting heap corruption.  The goal is to minimize the