From e07e405d7b1e06496a9a4819091205ee22ac7532 Mon Sep 17 00:00:00 2001
From: Ian Lance Taylor <iant@google.com>
Date: Fri, 1 Jun 2007 22:47:02 +0000
Subject: [PATCH] tree-vrp.c (compare_name_with_value): Always set
 used_strict_overflow if we get a result from the variable itself.

./:	* tree-vrp.c (compare_name_with_value): Always set
	used_strict_overflow if we get a result from the variable itself.
testsuite/:
	* gcc.dg/Wstrict-overflow-17.c: New test.

From-SVN: r125269
---
 gcc/ChangeLog                              |  5 +++++
 gcc/testsuite/ChangeLog                    |  4 ++++
 gcc/testsuite/gcc.dg/Wstrict-overflow-17.c | 20 ++++++++++++++++++++
 gcc/tree-vrp.c                             |  4 ++--
 4 files changed, 31 insertions(+), 2 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/Wstrict-overflow-17.c

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index ece60c7ae48..87d2444b48b 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2007-06-01  Ian Lance Taylor  <iant@google.com>
+
+	* tree-vrp.c (compare_name_with_value): Always set
+	used_strict_overflow if we get a result from the variable itself.
+
 2007-06-01  Ian Lance Taylor  <iant@google.com>
 
 	PR rtl-optimization/31455
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 9f011b00809..6d4256893a1 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2007-06-01  Ian Lance Taylor  <iant@google.com>
+
+	* gcc.dg/Wstrict-overflow-17.c: New test.
+
 2007-06-01  Kazu Hirata  <kazu@codesourcery.com>
 
 	* gcc.dg/builtin-return-1.c (g): New.
diff --git a/gcc/testsuite/gcc.dg/Wstrict-overflow-17.c b/gcc/testsuite/gcc.dg/Wstrict-overflow-17.c
new file mode 100644
index 00000000000..5625bc2a7f3
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/Wstrict-overflow-17.c
@@ -0,0 +1,20 @@
+/* { dg-do compile } */
+/* { dg-options "-fstrict-overflow -O2 -Wstrict-overflow" } */
+
+/* This erroneously gave an overflow warning.  */
+
+extern void bar (char);
+void
+foo (char *s)
+{
+  int len, i;
+
+  for (len = 1; len < 5000; ++len)
+    {
+      for (i = 0; i < len; ++i)
+	{
+	  if (s[i] != '\0')
+	    bar (s[i]);
+	}
+    }
+}
diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c
index 80744d67968..e0a55a86eac 100644
--- a/gcc/tree-vrp.c
+++ b/gcc/tree-vrp.c
@@ -4676,8 +4676,8 @@ compare_name_with_value (enum tree_code comp, tree var, tree val,
   equiv_vr = get_vr_for_comparison (SSA_NAME_VERSION (var));
   sop = false;
   retval = compare_range_with_value (comp, &equiv_vr, val, &sop);
-  if (sop)
-    used_strict_overflow = 1;
+  if (retval)
+    used_strict_overflow = sop ? 1 : 0;
 
   /* If the equiv set is empty we have done all work we need to do.  */
   if (e == NULL)