fold-const.c (fold_binary): Fold ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify.

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

	* fold-const.c (fold_binary): Fold ~(X ^ Y) to ~X ^ Y or X ^ ~Y if
	~X or ~Y simplify.

From-SVN: r98435

gcc/ChangeLog

 2005-04-19  James A. Morrison  <phython@gcc.gnu.org>
 
+	* fold-const.c (fold_binary): Fold ~(X ^ Y) to ~X ^ Y or X ^ ~Y if
+	~X or ~Y simplify.
+
+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>

gcc/fold-const.c

@@ -7015,6 +7015,20 @@ fold_unary (enum tree_code code, tree type, tree op0)
 		   || (TREE_CODE (arg0) == PLUS_EXPR
 		       && integer_all_onesp (TREE_OPERAND (arg0, 1)))))
 	return fold_build1 (NEGATE_EXPR, type, TREE_OPERAND (arg0, 0));
+      /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify.  */
+      else if (TREE_CODE (arg0) == BIT_XOR_EXPR
+	       && (tem = fold_unary (BIT_NOT_EXPR, type,
+			       	     fold_convert (type,
+					     	   TREE_OPERAND (arg0, 0)))))
+	return fold_build2 (BIT_XOR_EXPR, type, tem,
+			    fold_convert (type, TREE_OPERAND (arg0, 1)));
+      else if (TREE_CODE (arg0) == BIT_XOR_EXPR
+	       && (tem = fold_unary (BIT_NOT_EXPR, type,
+			       	     fold_convert (type,
+					     	   TREE_OPERAND (arg0, 1)))))
+	return fold_build2 (BIT_XOR_EXPR, type,
+			    fold_convert (type, TREE_OPERAND (arg0, 0)), tem);
+
       return NULL_TREE;
 
     case TRUTH_NOT_EXPR:

gcc/testsuite/ChangeLog

 2005-04-19  James A. Morrison  <phython@gcc.gnu.org>
 
 	* gcc.dg/fold-xor-1.c: New test.
+	* gcc.dg/fold-xor-2.c: New test.
 
 2005-04-19  James E. Wilson  <wilson@specifixinc.com>
 

gcc/testsuite/gcc.dg/fold-xor-2.c

+/* { dg-do compile } */
+/* { dg-options "-fdump-tree-generic" } */
+int f (int a, int b) {
+	return ~(a ^ -(b + 1));
+}
+
+int g (int a, int b) {
+	return b ^ a;
+}
+
+unsigned int h (unsigned int a, unsigned int b) {
+	return ~(-(b + 1) ^ a);
+}
+
+/* { dg-final { scan-tree-dump-times "b \\^ a" 3 "generic" } } */
+/* { dg-final { cleanup-tree-dump "generic" } } */