From: wilson <wilson@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Wed, 3 May 2000 20:04:31 +0000 (+0000)
Subject: Fix for ia64-linux misoptimization.
X-Git-Url: http://git.sourceforge.jp/view?p=pf3gnuchains%2Fgcc-fork.git;a=commitdiff_plain;h=6269027b068ccbaa98d5dd3e24d54ce65eac8960

Fix for ia64-linux misoptimization.
	* fold-const.c (extract_muldiv, case MAX_EXPR): Don't allow signedness
	change.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@33643 138bc75d-0d04-0410-961f-82ee72b054a4
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 96da99a3a13..d891f18dfad 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+Wed May  3 12:55:46 2000  Jim Wilson  <wilson@cygnus.com>
+
+	* fold-const.c (extract_muldiv, case MAX_EXPR): Don't allow signedness
+	change.
+
 2000-05-03  Greg McGary  <gkm@gnu.org>
 
 	* tree.h (tree_common): Add bounded_flag member.  Remove
diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index e0d0f00cb4e..95682876252 100644
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -4402,6 +4402,11 @@ extract_muldiv (t, c, code, wide_type)
       break;
 
     case MIN_EXPR:  case MAX_EXPR:
+      /* If widening the type changes the signedness, then we can't perform
+	 this optimization as that changes the result.  */
+      if (ctype != type && TREE_UNSIGNED (ctype) != TREE_UNSIGNED (type))
+	break;
+
       /* MIN (a, b) / 5 -> MIN (a / 5, b / 5)  */
       if ((t1 = extract_muldiv (op0, c, code, wide_type)) != 0
 	  && (t2 = extract_muldiv (op1, c, code, wide_type)) != 0)