tree-ssa-ccp.c (ccp_fold): Fold VIEW_CONVERT_EXPRs of constants.

2008-08-21  Richard Guenther  <rguenther@suse.de>

	* tree-ssa-ccp.c (ccp_fold): Fold VIEW_CONVERT_EXPRs of constants.

	* gcc.dg/vect/vect-fold-1.c: Scan ccp1 dump instead of dom1.

From-SVN: r139398

gcc/ChangeLog

+2008-08-21  Richard Guenther  <rguenther@suse.de>
+
+	* tree-ssa-ccp.c (ccp_fold): Fold VIEW_CONVERT_EXPRs of constants.
+
 2008-08-21  Jan Hubicka  <jh@suse.cz>
 
 	* cgraph.c (first_cgraph_function_insertion_hook): New variable.

gcc/testsuite/ChangeLog

 2008-08-21  Richard Guenther  <rguenther@suse.de>
 
+	* gcc.dg/vect/vect-fold-1.c: Scan ccp1 dump instead of dom1.
+
+2008-08-21  Richard Guenther  <rguenther@suse.de>
+
 	PR middle-end/36817
 	* gcc.c-torture/compile/pr36817.c: New testcase.
 

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

 /* { dg-do compile } */
-/* { dg-options "-O2 -fdump-tree-dom1" } */
+/* { dg-options "-O2 -fdump-tree-ccp1" } */
 
 typedef unsigned char v4qi __attribute__ ((vector_size (4)));
 
@@ -12,5 +12,5 @@ void foo()
   c = a + b;
 }
 
-/* { dg-final { scan-tree-dump-times "c = { 6, 8, 10, 12 }" 1 "dom1" } } */
-/* { dg-final { cleanup-tree-dump "dom1" } } */
+/* { dg-final { scan-tree-dump-times "c =.* { 6, 8, 10, 12 }" 1 "ccp1" } } */
+/* { dg-final { cleanup-tree-dump "ccp1" } } */

gcc/tree-ssa-ccp.c

@@ -961,7 +961,17 @@ ccp_fold (gimple stmt)
                 }
 
               if (kind == tcc_reference)
-                return fold_const_aggregate_ref (rhs);
+		{
+		  if (TREE_CODE (rhs) == VIEW_CONVERT_EXPR
+		      && TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME)
+		    {
+		      prop_value_t *val = get_value (TREE_OPERAND (rhs, 0));
+		      if (val->lattice_val == CONSTANT)
+			return fold_unary (VIEW_CONVERT_EXPR,
+					   TREE_TYPE (rhs), val->value);
+		    }
+		  return fold_const_aggregate_ref (rhs);
+		}
               else if (kind == tcc_declaration)
                 return get_symbol_constant_value (rhs);
               return rhs;