fold-const (fold_binary): Fold ~X ^ ~ Y to X ^ Y.

2005-04-19  James A. Morrison  <phython@gcc.gnu.org>

	* fold-const (fold_binary):  Fold ~X ^ ~ Y to X ^ Y.

From-SVN: r98434

gcc/ChangeLog

+2005-04-19  James A. Morrison  <phython@gcc.gnu.org>
+
+	* fold-const (fold_binary):  Fold ~X ^ ~ Y to X ^ Y.
+
 2005-04-20  Michael Pogue  <michael.pogue@sun.com>
             Joseph S. Myers  <joseph@codesourcery.com>
 

gcc/fold-const.c

@@ -8174,6 +8174,13 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1)
 	  goto bit_ior;
 	}
 
+      /* Convert ~X ^ ~Y to X ^ Y.  */
+      if (TREE_CODE (arg0) == BIT_NOT_EXPR
+	  && TREE_CODE (arg1) == BIT_NOT_EXPR)
+	return fold_build2 (code, type,
+			    fold_convert (type, TREE_OPERAND (arg0, 0)),
+			    fold_convert (type, TREE_OPERAND (arg1, 0)));
+
       /* See if this can be simplified into a rotate first.  If that
 	 is unsuccessful continue in the association code.  */
       goto bit_rotate;

gcc/testsuite/ChangeLog

+2005-04-19  James A. Morrison  <phython@gcc.gnu.org>
+
+	* gcc.dg/fold-xor-1.c: New test.
+
 2005-04-19  James E. Wilson  <wilson@specifixinc.com>
 
 	PR target/20670

gcc/testsuite/gcc.dg/fold-xor-1.c

+/* { dg-do compile } */
+/* { dg-options "-fdump-tree-generic" } */
+
+int f (int a, int b) {
+  return ~a ^ ~b;
+}
+
+unsigned int g (unsigned int a, unsigned int b) {
+  return ~a ^ ~b;
+}
+/* { dg-final { scan-tree-dump-times "a \\^ b" 2 "generic" } } */
+/* { dg-final { cleanup-tree-dump "generic" } } */