From: Richard Guenther <rguenther@suse.de>
Date: Sun, 17 Feb 2008 14:00:48 +0000 (+0000)
Subject: re PR tree-optimization/35231 (VRP miscompiles libX11)
X-Git-Tag: releases/gcc-4.3.0~120
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=e09deb1401d411beebe1f56c8435bb9af8e1f4cc;p=thirdparty%2Fgcc.git

re PR tree-optimization/35231 (VRP miscompiles libX11)

2008-02-17  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/35231
	* tree-vrp.c (register_edge_assert_for): Do not assume A == 0
	if A | B != 1.

	* gcc.c-torture/execute/pr35231.c: New testcase.

From-SVN: r132378
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index b75e608e9ef8..946eb6a70030 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2008-02-17  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/35231
+	* tree-vrp.c (register_edge_assert_for): Do not assume A == 0
+	if A | B != 1.
+
 2008-02-17  Uros Bizjak  <ubizjak@gmail.com>
 
 	Revert:
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 8bfa223a170e..c167949098c6 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2008-02-17  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/35231
+	* gcc.c-torture/execute/pr35231.c: New testcase.
+
 2008-02-17  Uros Bizjak  <ubizjak@gmail.com>
 
 	* gcc.target/i386/pr32268.c (test_lt): Add noinline attribute.
diff --git a/gcc/testsuite/gcc.c-torture/execute/pr35231.c b/gcc/testsuite/gcc.c-torture/execute/pr35231.c
new file mode 100644
index 000000000000..e0327eb5f8a5
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr35231.c
@@ -0,0 +1,16 @@
+extern void abort(void);
+
+int __attribute__((noinline))
+foo(int bits_per_pixel, int depth)
+{
+  if ((bits_per_pixel | depth) == 1)
+    abort ();
+  return bits_per_pixel;
+}
+
+int main()
+{
+  if (foo(2, 0) != 2)
+    abort ();
+  return 0;
+}
diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c
index 5f9a3279aa3c..f9615d1f815e 100644
--- a/gcc/tree-vrp.c
+++ b/gcc/tree-vrp.c
@@ -3753,7 +3753,11 @@ register_edge_assert_for (tree name, edge e, block_stmt_iterator si, tree cond)
 
       if (TREE_CODE (def_stmt) == GIMPLE_MODIFY_STMT
 	  && (TREE_CODE (GIMPLE_STMT_OPERAND (def_stmt, 1)) == TRUTH_OR_EXPR
-	      || TREE_CODE (GIMPLE_STMT_OPERAND (def_stmt, 1)) == BIT_IOR_EXPR))
+	      /* For BIT_IOR_EXPR only if NAME == 0 both operands have
+		 necessarily zero value.  */
+	      || (comp_code == EQ_EXPR
+		  && (TREE_CODE (GIMPLE_STMT_OPERAND (def_stmt, 1))
+		        == BIT_IOR_EXPR))))
 	{
 	  tree op0 = TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt, 1), 0);
 	  tree op1 = TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt, 1), 1);