[backport from gcc-4.7/trunk r183214 <mikpe@it.uu.se>]

gcc/

2012-01-16  Jan Hubicka  <jh@suse.cz>

	PR c/12245
	PR c++/14179
	* convert.c (convert_to_integer): Use fold_convert for
	converting an INTEGER_CST to integer type.

--- gcc-4.6.2/gcc/convert.c.~1~	2011-10-12 13:57:36.000000000 +0200
+++ gcc-4.6.2/gcc/convert.c	2012-01-18 16:28:38.000000000 +0100
@@ -842,6 +842,10 @@ convert_to_integer (tree type, tree expr
 	  break;
 	}
 
+      /* When parsing long initializers, we might end up with a lot of casts.
+	 Shortcut this.  */
+      if (TREE_CODE (expr) == INTEGER_CST)
+	return fold_convert (type, expr);
       return build1 (CONVERT_EXPR, type, expr);
 
     case REAL_TYPE: