fold-const.c (fold_unary): Fold (T1)(~(T2)X) as ~(T1)X...

	* fold-const.c (fold_unary) <NOP_EXPR>: Fold (T1)(~(T2)X) as
	~(T1)X, when T1 and T2 are integer types of the same precision
	and (T2)X isn't an extension.

	* gcc.dg/fold-convnotconv-1.c: New test case.

From-SVN: r112455

gcc/ChangeLog

+2006-03-28  Roger Sayle  <roger@eyesopen.com>
+
+	* fold-const.c (fold_unary) <NOP_EXPR>: Fold (T1)(~(T2)X) as
+	~(T1)X, when T1 and T2 are integer types of the same precision
+	and (T2)X isn't an extension.
+
 2006-03-28  Jeff Law  <law@redhat.com>
 
 	PR tree-optimization/26796

gcc/fold-const.c

@@ -7074,6 +7074,22 @@ fold_unary (enum tree_code code, tree type, tree op0)
 			   TREE_OPERAND (arg0, 1));
 	}
 
+      /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
+	 of the same precision, and X is a integer type not narrower than
+	 types T1 or T2, i.e. the cast (T2)X isn't an extension.  */
+      if (INTEGRAL_TYPE_P (type)
+	  && TREE_CODE (op0) == BIT_NOT_EXPR
+	  && INTEGRAL_TYPE_P (TREE_TYPE (op0))
+	  && (TREE_CODE (TREE_OPERAND (op0, 0)) == NOP_EXPR
+	      || TREE_CODE (TREE_OPERAND (op0, 0)) == CONVERT_EXPR)
+	  && TYPE_PRECISION (type) == TYPE_PRECISION (TREE_TYPE (op0)))
+	{
+	  tem = TREE_OPERAND (TREE_OPERAND (op0, 0), 0);
+	  if (INTEGRAL_TYPE_P (TREE_TYPE (tem))
+	      && TYPE_PRECISION (type) <= TYPE_PRECISION (TREE_TYPE (tem)))
+	    return fold_build1 (BIT_NOT_EXPR, type, fold_convert (type, tem));
+	}
+
       tem = fold_convert_const (code, type, arg0);
       return tem ? tem : NULL_TREE;
 

gcc/testsuite/ChangeLog

+2006-03-28  Roger Sayle  <roger@eyesopen.com>
+
+	* gcc.dg/fold-convnotconv-1.c: New test case.
+
 2006-03-28 Paul Thomas <pault@gcc.gnu.org>
 
 	PR fortran/26779

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

+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-original" } */
+
+int test1(int a)
+{
+  return ~(unsigned int)a;
+}
+
+unsigned int test2(unsigned int b)
+{
+  return ~(int)b;
+}
+
+/* { dg-final { scan-tree-dump-times "~a" 1 "original" } } */
+/* { dg-final { scan-tree-dump-times "~b" 1 "original" } } */
+/* { dg-final { cleanup-tree-dump "original" } } */
+