re PR tree-optimization/66757 (wrong code at -O1 and above on x86_64-linux-gnu)

	PR tree-optimization/66757
	* match.pd: Add missing condition to ~X ^ C -> X ^ ~C.

From-SVN: r225446

gcc/ChangeLog

+2015-07-06  Eric Botcazou  <ebotcazou@adacore.com>
+
+	PR tree-optimization/66757
+	* match.pd: Add missing condition to ~X ^ C -> X ^ ~C.
+
 2015-07-05  Chung-Lin Tang  <cltang@codesourcery.com>
 	    Sandra Loosemore <sandra@codesourcery.com>
 

gcc/match.pd

@@ -444,7 +444,8 @@ along with GCC; see the file COPYING3.  If not see
 /* Convert ~X ^ C to X ^ ~C.  */
 (simplify
  (bit_xor (convert? (bit_not @0)) INTEGER_CST@1)
- (bit_xor (convert @0) (bit_not @1)))
+ (if (tree_nop_conversion_p (type, TREE_TYPE (@0)))
+  (bit_xor (convert @0) (bit_not @1))))
 
 /* Fold (X & Y) ^ Y as ~X & Y.  */
 (simplify

gcc/testsuite/ChangeLog

+2015-07-06  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* gcc.c-torture/execute/pr66757.c: New test.
+
 2015-07-06  Bin Cheng  <bin.cheng@arm.com>
 
 	PR tree-optimization/66720
-	* gcc.dg/vect/pr48052.c: Use dg-require-effective-target
-	vect_int_mult.
+	* gcc.dg/vect/pr48052.c: Use dg-require-effective-target vect_int_mult.
 
 2015-07-05  Chung-Lin Tang  <cltang@codesourcery.com>
 	    Sandra Loosemore <sandra@codesourcery.com>

gcc/testsuite/gcc.c-torture/execute/pr66757.c

+/* PR tree-optimization/66757 */
+/* Testcase by Zhendong Su <su@cs.ucdavis.edu> */
+
+int a, b;
+
+int
+main (void)
+{
+  unsigned int t = (unsigned char) (~b); 
+
+  if ((t ^ 1) / 255)
+    __builtin_abort (); 
+
+  return 0;
+}