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authorAnton Blanchard <anton@samba.org>2016-01-04 13:28:52 -0200
committerTulio Magno Quites Machado Filho <tuliom@linux.vnet.ibm.com>2016-01-04 14:55:38 -0200
commit0a1f1e78fbdfaf2c01e9c2368023b2533e7136cf (patch)
tree1e451d9c004d8e38228c8ead00b042c4bdac1ee4
parent1979f3c1ad7a6ae30de5c9cd162729b29488cece (diff)
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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.
-rw-r--r--ChangeLog6
-rw-r--r--sysdeps/ieee754/dbl-64/e_pow.c6
2 files changed, 10 insertions, 2 deletions
diff --git a/ChangeLog b/ChangeLog
index bea73e3582..de8a1bcb65 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 2ff2bb6e56..663fa392c2 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;