From fc452262ebb71eb43eadca98d04548e3b3bcf009 Mon Sep 17 00:00:00 2001
From: rth <rth@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Fri, 14 Apr 2000 17:45:17 +0000
Subject: [PATCH] * fold-const.c (extract_muldiv): Don't distribute and
widen multiply across plus for non-sizetype unsigned types.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@33151 138bc75d-0d04-0410-961f-82ee72b054a4
---
gcc/ChangeLog | 5 +++++
gcc/fold-const.c | 8 ++++++++
2 files changed, 13 insertions(+)
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 4465c292dfcd..29c1d1f22c86 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2000-04-14 Richard Henderson <rth@cygnus.com>
+
+ * fold-const.c (extract_muldiv): Don't distribute and widen
+ multiply across plus for non-sizetype unsigned types.
+
2000-04-14 Richard Henderson <rth@cygnus.com>
* flow.c (find_auto_inc): Don't autoinc eliminable registers.
diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index 19b2f7032011..991dddda9730 100644
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -4480,6 +4480,14 @@ extract_muldiv (t, c, code, wide_type)
if (op1 == 0 || TREE_OVERFLOW (op1))
break;
+ /* If we have an unsigned type is not a sizetype, we cannot widen
+ the operation since it will change the result if the original
+ computation overflowed. */
+ if (TREE_UNSIGNED (ctype)
+ && ! TYPE_IS_SIZETYPE (ctype)
+ && ctype != type)
+ break;
+
/* If we were able to eliminate our operation from the first side,
apply our operation to the second side and reform the PLUS. */
if (t1 != 0 && (TREE_CODE (t1) != code || code == MULT_EXPR))
--
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