From: Anton Blanchard <anton@samba.org>
Date: Mon, 4 Jan 2016 15:28:52 +0000 (-0200)
Subject: Eliminate redundant sign extensions in pow()
X-Git-Tag: glibc-2.23~85
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0a1f1e78fbdfaf2c01e9c2368023b2533e7136cf;p=thirdparty%2Fglibc.git

Eliminate redundant sign extensions in pow()

When looking at the code generated for pow() on ppc64 I noticed quite
a few sign extensions. Making the array indices unsigned reduces the
number of sign extensions from 24 to 7.

Tested for powerpc64le and x86_64.
---

diff --git a/ChangeLog b/ChangeLog
index bea73e35824..de8a1bcb656 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2016-01-04  Anton Blanchard  <anton@samba.org>
+
+	* sysdeps/ieee754/dbl-64/e_pow.c (log1): Use unsigned int
+	for array indices.
+	* sysdeps/ieee754/dbl-64/e_pow.c (my_log2): Likewise.
+
 2016-01-04  Joseph Myers  <joseph@codesourcery.com>
 
 	* NEWS: Update copyright dates.
diff --git a/sysdeps/ieee754/dbl-64/e_pow.c b/sysdeps/ieee754/dbl-64/e_pow.c
index 2ff2bb6e569..663fa392c29 100644
--- a/sysdeps/ieee754/dbl-64/e_pow.c
+++ b/sysdeps/ieee754/dbl-64/e_pow.c
@@ -245,7 +245,8 @@ static double
 SECTION
 log1 (double x, double *delta, double *error)
 {
-  int i, j, m;
+  unsigned int i, j;
+  int m;
   double uu, vv, eps, nx, e, e1, e2, t, t1, t2, res, add = 0;
   mynumber u, v;
 #ifdef BIG_ENDI
@@ -344,7 +345,8 @@ static double
 SECTION
 my_log2 (double x, double *delta, double *error)
 {
-  int i, j, m;
+  unsigned int i, j;
+  int m;
   double uu, vv, eps, nx, e, e1, e2, t, t1, t2, res, add = 0;
   double ou1, ou2, lu1, lu2, ov, lv1, lv2, a, a1, a2;
   double y, yy, z, zz, j1, j2, j7, j8;