From: Richard Guenther <rguenther@suse.de>
Date: Mon, 29 Jun 2009 14:52:20 +0000 (+0000)
Subject: re PR tree-optimization/40579 (gcc -O2 optimization causes infinite loop and wrong... 
X-Git-Tag: releases/gcc-4.3.4~101
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2a8db7532fbfe5aaeb7281c16e5ed9e35622f7cb;p=thirdparty%2Fgcc.git

re PR tree-optimization/40579 (gcc -O2 optimization causes infinite loop and wrong output)

2009-06-29  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/40579
	* tree-vrp.c (vrp_evaluate_conditional_warnv): Bail out early if
	the IL to simplify has constants that overflowed.

	* gcc.c-torture/execute/pr40579.c: New testcase.

From-SVN: r149052
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index a1763870e0df..63ca404ef9ce 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2009-06-29  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/40579
+	* tree-vrp.c (vrp_evaluate_conditional_warnv): Bail out early if
+	the IL to simplify has constants that overflowed.
+
 2009-06-28  Uros Bizjak  <ubizjak@gmail.com>
 
 	PR tree-optimization/40550
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index c5d17fef3798..d3ec47688058 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2009-06-29  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/40579
+	* gcc.c-torture/execute/pr40579.c: New testcase.
+
 2009-06-28  Uros Bizjak  <ubizjak@gmail.com>
 
 	PR tree-optimization/40550
diff --git a/gcc/testsuite/gcc.c-torture/execute/pr40579.c b/gcc/testsuite/gcc.c-torture/execute/pr40579.c
new file mode 100644
index 000000000000..7f44af310e7b
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr40579.c
@@ -0,0 +1,28 @@
+extern void abort (void);
+static char * __attribute__((noinline))
+itos(int num)
+{
+  return (char *)0;
+}
+static void __attribute__((noinline))
+foo(int i, const char *x)
+{
+  if (i >= 4)
+    abort ();
+}
+int main()
+{
+  int x = -__INT_MAX__ + 3;
+  int i;
+
+  for (i = 0; i < 4; ++i)
+    {
+      char *p;
+      --x;
+      p = itos(x);
+      foo(i, p);
+    }
+
+  return 0;
+}
+
diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c
index 4a20c74738ec..53f910d97d65 100644
--- a/gcc/tree-vrp.c
+++ b/gcc/tree-vrp.c
@@ -4989,6 +4989,14 @@ vrp_evaluate_conditional_warnv (tree cond, bool use_equiv_p,
       tree op0 = TREE_OPERAND (cond, 0);
       tree op1 = TREE_OPERAND (cond, 1);
 
+      /* Some passes and foldings leak constants with overflow flag set
+	 into the IL.  Avoid doing wrong things with these and bail out.  */
+      if ((TREE_CODE (op0) == INTEGER_CST
+	   && TREE_OVERFLOW (op0))
+	  || (TREE_CODE (op1) == INTEGER_CST
+	      && TREE_OVERFLOW (op1)))
+	return NULL_TREE;
+
       /* We only deal with integral and pointer types.  */
       if (!INTEGRAL_TYPE_P (TREE_TYPE (op0))
 	  && !POINTER_TYPE_P (TREE_TYPE (op0)))