Index: cvt.c
===================================================================
--- cvt.c	(revision 204536)
+++ cvt.c	(working copy)
@@ -629,7 +629,8 @@ cp_convert_and_check (tree type, tree expr, tsubst
     {
       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.  */