From: Jakub Jelinek <jakub@redhat.com>
Date: Mon, 4 Aug 2014 15:46:33 +0000 (+0200)
Subject: * runtime/memory.c (xmallocarray): Avoid division for the common case.
X-Git-Tag: releases/gcc-5.1.0~5664
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=62c986afde031d141961d2619a860def836c8e9b;p=thirdparty%2Fgcc.git

* runtime/memory.c (xmallocarray): Avoid division for the common case.

From-SVN: r213593
---

diff --git a/libgfortran/ChangeLog b/libgfortran/ChangeLog
index 80f87523a695..77afd166d075 100644
--- a/libgfortran/ChangeLog
+++ b/libgfortran/ChangeLog
@@ -1,3 +1,7 @@
+2014-08-04  Jakub Jelinek  <jakub@redhat.com>
+
+	* runtime/memory.c (xmallocarray): Avoid division for the common case.
+
 2014-07-20  Jerry DeLisle  <jvdelisle@gcc.gnu.org>
 
 	PR libgfortran/61632
diff --git a/libgfortran/runtime/memory.c b/libgfortran/runtime/memory.c
index 501d870b83ca..16f06065e2b5 100644
--- a/libgfortran/runtime/memory.c
+++ b/libgfortran/runtime/memory.c
@@ -56,7 +56,9 @@ xmallocarray (size_t nmemb, size_t size)
 
   if (!nmemb || !size)
     size = nmemb = 1;
-  else if (nmemb > SIZE_MAX / size)
+#define HALF_SIZE_T (((size_t) 1) << (__CHAR_BIT__ * sizeof (size_t) / 2))
+  else if (__builtin_expect ((nmemb | size) >= HALF_SIZE_T, 0)
+	   && nmemb > SIZE_MAX / size)
     {
       errno = ENOMEM;
       os_error ("Integer overflow in xmallocarray");