fold-const.c (tree_expr_nonnegative_p): Handle BIT_XOR_EXPR like BIT_IOR_EXPR...

	* fold-const.c (tree_expr_nonnegative_p): Handle BIT_XOR_EXPR like
	BIT_IOR_EXPR; A^B is nonnegative when A and B are nonnegative.

	* gcc.dg/compare8.c: Add an additional test for XOR.

From-SVN: r79979

gcc/ChangeLog

+2004-03-25  Roger Sayle  <roger@eyesopen.com>
+
+	* fold-const.c (tree_expr_nonnegative_p): Handle BIT_XOR_EXPR like
+	BIT_IOR_EXPR; A^B is nonnegative when A and B are nonnegative.
+
 2004-03-25  Richard Henderson  <rth@redhat.com>
 
 	PR 11527

gcc/fold-const.c

@@ -8722,6 +8722,7 @@ tree_expr_nonnegative_p (tree t)
       return tree_expr_nonnegative_p (TREE_OPERAND (t, 1))
 	     || tree_expr_nonnegative_p (TREE_OPERAND (t, 0));
     case BIT_IOR_EXPR:
+    case BIT_XOR_EXPR:
       return tree_expr_nonnegative_p (TREE_OPERAND (t, 0))
 	     && tree_expr_nonnegative_p (TREE_OPERAND (t, 1));
 

gcc/testsuite/ChangeLog

+2004-03-25  Roger Sayle  <roger@eyesopen.com>
+
+	* gcc.dg/compare8.c: Add an additional test for XOR.
+
 2004-03-25  Kaveh R. Ghazi  <ghazi@caip.rutgers.edu>
 
 	* gcc.dg/torture/builtin-ctype-1.c: New test.

gcc/testsuite/gcc.dg/compare8.c

@@ -13,3 +13,9 @@ g(unsigned short a1, unsigned short a2, unsigned int b)
   return ((a1+a2)&5) > b ? 2 : 3;  /* { dg-bogus "signed and unsigned" } */
 }
 
+int
+h(unsigned short a1, unsigned short a2, unsigned int b)
+{
+  return ((a1+a2)^5) > b ? 2 : 3;  /* { dg-bogus "signed and unsigned" } */
+}
+