re PR tree-optimization/63665 (wrong code with signed overflow even with -fwrapv)

2014-10-28  Richard Biener  <rguenther@suse.de>

	PR middle-end/63665
	* fold-const.c (fold_comparison): Properly guard simplifying
	against INT_MAX/INT_MIN with !TYPE_OVERFLOW_WRAPS.

	* gcc.dg/pr63665.c: New testcase.

From-SVN: r216781

gcc/ChangeLog

+2014-10-28  Richard Biener  <rguenther@suse.de>
+
+	PR middle-end/63665
+	* fold-const.c (fold_comparison): Properly guard simplifying
+	against INT_MAX/INT_MIN with !TYPE_OVERFLOW_WRAPS.
+
 2014-10-28  Alan Lawrence  <alan.lawrence@arm.com>
 
 	* expr.c (expand_expr_real_2): Remove code handling VEC_LSHIFT_EXPR.

gcc/fold-const.c

@@ -8749,7 +8749,8 @@ fold_comparison (location_t loc, enum tree_code code, tree type,
 
       /* If the constant operation overflowed this can be
 	 simplified as a comparison against INT_MAX/INT_MIN.  */
-      if (TREE_OVERFLOW (new_const))
+      if (TREE_OVERFLOW (new_const)
+	  && !TYPE_OVERFLOW_WRAPS (TREE_TYPE (arg0)))
 	{
 	  int const1_sgn = tree_int_cst_sgn (const1);
 	  enum tree_code code2 = code;

gcc/testsuite/ChangeLog

+2014-10-28  Richard Biener  <rguenther@suse.de>
+
+	PR middle-end/63665
+	* gcc.dg/pr63665.c: New testcase.
+
 2014-10-28  Yury Gribov  <y.gribov@samsung.com>
 
 	* c-c++-common/asan/kasan-recover-1.c: New test.

gcc/testsuite/gcc.dg/pr63665.c

+/* { dg-do run } */
+/* { dg-require-effective-target int32plus } */
+/* { dg-options "-O -fno-tree-ccp -fno-tree-fre -fno-tree-copy-prop -fwrapv" } */
+
+static inline int
+test5 (int x)
+{
+  int y = 0x80000000;
+  return x + y;
+}
+
+int
+main ()
+{
+  if (test5 (0x80000000) != 0)
+    __builtin_abort ();
+  return 0;
+}