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GNU C Library master sources branch, master, updated. glibc-2.14-386-g99ce7b0
- From: drepper at sourceware dot org
- To: glibc-cvs at sourceware dot org
- Date: 18 Oct 2011 03:16:49 -0000
- Subject: GNU C Library master sources branch, master, updated. glibc-2.14-386-g99ce7b0
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http://sources.redhat.com/git/gitweb.cgi?p=glibc.git;a=commitdiff;h=99ce7b04edf17821a6abd19844f10e8c1cd3c724
commit 99ce7b04edf17821a6abd19844f10e8c1cd3c724
Author: Ulrich Drepper <drepper@gmail.com>
Date: Mon Oct 17 23:16:34 2011 -0400
Small optimization of generic exp2
diff --git a/ChangeLog b/ChangeLog
index c47826c..ad7db01 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,7 @@
2011-10-17 Ulrich Drepper <drepper@gmail.com>
+ * sysdeps/ieee754/dbl-64/e_exp2.c (__ieee754_exp2): Small optimization.
+
* sysdeps/ieee754/dbl-64/wordsize-64/s_frexp.c: New file.
* sysdeps/x86_64/fpu/math_private.h: Relax asm requirements for
diff --git a/sysdeps/ieee754/dbl-64/e_exp2.c b/sysdeps/ieee754/dbl-64/e_exp2.c
index 674cdb0..c973f35 100644
--- a/sysdeps/ieee754/dbl-64/e_exp2.c
+++ b/sysdeps/ieee754/dbl-64/e_exp2.c
@@ -53,8 +53,19 @@ __ieee754_exp2 (double x)
static const double lomark = (double) (DBL_MIN_EXP - DBL_MANT_DIG - 1);
/* Check for usual case. */
- if (isless (x, himark) && isgreaterequal (x, lomark))
+ if (__builtin_expect (isless (x, himark), 1))
{
+ /* Exceptional cases: */
+ if (__builtin_expect (! isgreaterequal (x, lomark), 0))
+ {
+ if (__isinf (x))
+ /* e^-inf == 0, with no error. */
+ return 0;
+ else
+ /* Underflow */
+ return TWOM1000 * TWOM1000;
+ }
+
static const double THREEp42 = 13194139533312.0;
int tval, unsafe;
double rx, x22, result;
@@ -120,16 +131,6 @@ __ieee754_exp2 (double x)
else
return result * scale_u.d;
}
- /* Exceptional cases: */
- else if (isless (x, himark))
- {
- if (__isinf (x))
- /* e^-inf == 0, with no error. */
- return 0;
- else
- /* Underflow */
- return TWOM1000 * TWOM1000;
- }
else
/* Return x, if x is a NaN or Inf; or overflow, otherwise. */
return TWO1023*x;
-----------------------------------------------------------------------
Summary of changes:
ChangeLog | 2 ++
sysdeps/ieee754/dbl-64/e_exp2.c | 23 ++++++++++++-----------
2 files changed, 14 insertions(+), 11 deletions(-)
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