tree-ssa-forwprop.c (forward_propagate_into_comparison): Do not make the…

tree-ssa-forwprop.c (forward_propagate_into_comparison): Do not make the replacement if the conversion to the LHS type is not useless.

	* tree-ssa-forwprop.c (forward_propagate_into_comparison): Do not make
	the replacement if the conversion to the LHS type is not useless.

From-SVN: r179730

gcc/ChangeLog

+2011-10-09  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* tree-ssa-forwprop.c (forward_propagate_into_comparison): Do not make
+	the replacement if the conversion to the LHS type is not useless.
+
 2011-10-09  Ira Rosen  <ira.rosen@linaro.org>
 
 	PR tree-optimization/50635

gcc/tree-ssa-forwprop.c

@@ -465,16 +465,15 @@ forward_propagate_into_comparison (gimple_stmt_iterator *gsi)
   gimple stmt = gsi_stmt (*gsi);
   tree tmp;
   bool cfg_changed = false;
+  tree type = TREE_TYPE (gimple_assign_lhs (stmt));
   tree rhs1 = gimple_assign_rhs1 (stmt);
   tree rhs2 = gimple_assign_rhs2 (stmt);
 
   /* Combine the comparison with defining statements.  */
   tmp = forward_propagate_into_comparison_1 (stmt,
 					     gimple_assign_rhs_code (stmt),
-					     TREE_TYPE
-					       (gimple_assign_lhs (stmt)),
-					     rhs1, rhs2);
-  if (tmp)
+					     type, rhs1, rhs2);
+  if (tmp && useless_type_conversion_p (type, TREE_TYPE (tmp)))
     {
       gimple_assign_set_rhs_from_tree (gsi, tmp);
       fold_stmt (gsi);