cvt.c (cp_convert_and_check): Avoid calling cp_convert unnecessarily.

2013-11-26  Paolo Carlini  <paolo.carlini@oracle.com>

	* cvt.c (cp_convert_and_check): Avoid calling cp_convert
	unnecessarily.

From-SVN: r205387

gcc/cp/ChangeLog

+2013-11-26  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	* cvt.c (cp_convert_and_check): Avoid calling cp_convert
+	unnecessarily.
+
 2013-11-25  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	PR c++/54485

gcc/cp/cvt.c

@@ -630,7 +630,8 @@ cp_convert_and_check (tree type, tree expr, tsubst_flags_t complain)
     {
       tree folded = maybe_constant_value (expr);
       tree stripped = folded;
-      tree folded_result = cp_convert (type, folded, complain);
+      tree folded_result
+	= folded != expr ? cp_convert (type, folded, complain) : result;
 
       /* maybe_constant_value wraps an INTEGER_CST with TREE_OVERFLOW in a
 	 NOP_EXPR so that it isn't TREE_CONSTANT anymore.  */