From 9605a6060a15c8d9295b033bc847b352b1280219 Mon Sep 17 00:00:00 2001
From: Richard Guenther <rguenther@suse.de>
Date: Tue, 9 Feb 2010 11:34:28 +0000
Subject: [PATCH] re PR tree-optimization/43000 (VRP miscompiles python with
 -fwrapv)

2010-02-09  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/43000
	* tree-vrp.c (vrp_int_const_binop): Only handle unsigned
	arithmetic manually.

	* gcc.dg/torture/pr43000.c: New testcase.
	* gcc.dg/torture/pr43002.c: Likewise.

From-SVN: r156621
---
 gcc/ChangeLog                          |  6 ++++++
 gcc/testsuite/ChangeLog                |  6 ++++++
 gcc/testsuite/gcc.dg/torture/pr43000.c | 24 ++++++++++++++++++++++++
 gcc/testsuite/gcc.dg/torture/pr43002.c | 16 ++++++++++++++++
 gcc/tree-vrp.c                         |  6 +++---
 5 files changed, 55 insertions(+), 3 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/torture/pr43000.c
 create mode 100644 gcc/testsuite/gcc.dg/torture/pr43002.c

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index e9a82c9a552..73e2be6d313 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2010-02-09  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/43000
+	* tree-vrp.c (vrp_int_const_binop): Only handle unsigned
+	arithmetic manually.
+
 2010-02-08  Jakub Jelinek  <jakub@redhat.com>
 
 	PR tree-optimization/42931
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index c92c4284057..bbc21ec2aa9 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2010-02-09  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/43000
+	* gcc.dg/torture/pr43000.c: New testcase.
+	* gcc.dg/torture/pr43002.c: Likewise.
+
 2010-02-09  Daniel Kraft  <d@domob.eu>
 
 	PR fortran/39171
diff --git a/gcc/testsuite/gcc.dg/torture/pr43000.c b/gcc/testsuite/gcc.dg/torture/pr43000.c
new file mode 100644
index 00000000000..c1123375000
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr43000.c
@@ -0,0 +1,24 @@
+/* { dg-do run } */
+/* { dg-options "-fwrapv" } */
+
+int __attribute__((noinline))
+foo (long i, long j)
+{
+  if (i >= 1)
+    if (j > -(long)(((unsigned long)(long)-1)>>1))
+      {
+        long x;
+	j--;
+	x = i + j;
+	if (x >= 0)
+	  return 1;
+      }
+  return 0;
+}
+extern void abort (void);
+int main()
+{
+  if (foo (1, 1) != 1)
+    abort ();
+  return 0;
+}
diff --git a/gcc/testsuite/gcc.dg/torture/pr43002.c b/gcc/testsuite/gcc.dg/torture/pr43002.c
new file mode 100644
index 00000000000..f28a9102b3b
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr43002.c
@@ -0,0 +1,16 @@
+/* { dg-do compile } */
+/* { dg-options "-Wall -fwrapv" } */
+
+long A[4], B[100];
+
+void foo(void)
+{
+  int i, j, k = 3;
+  while (A[k] && k > 0) k--; /* k = {0, 1, 2, 3} */
+  for (i = 3 - k; i >= 0; i--) /* i = {0..3-k} */
+    for (j = 0; j <= k; j++) { /* line 8; j = {0..k} */
+	B[i + j] = 0; /* line 9; i + j = {0..3-k+k} = {0..3} */
+	for (j = 0; j <= k; j++); /* only one iteration is done, with j == 0 */
+    }
+}
+
diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c
index c1ba16a04c2..73dcf23a558 100644
--- a/gcc/tree-vrp.c
+++ b/gcc/tree-vrp.c
@@ -1898,9 +1898,9 @@ vrp_int_const_binop (enum tree_code code, tree val1, tree val2)
 
   res = int_const_binop (code, val1, val2, 0);
 
-  /* If we are not using wrapping arithmetic, operate symbolically
-     on -INF and +INF.  */
-  if (TYPE_OVERFLOW_WRAPS (TREE_TYPE (val1)))
+  /* If we are using unsigned arithmetic, operate symbolically
+     on -INF and +INF as int_const_binop only handles signed overflow.  */
+  if (TYPE_UNSIGNED (TREE_TYPE (val1)))
     {
       int checkz = compare_values (res, val1);
       bool overflow = false;