Index: wp-includes/post-template.php
===================================================================
--- wp-includes/post-template.php	(revision 15520)
+++ wp-includes/post-template.php	(working copy)
@@ -224,8 +224,10 @@
 		}
 
 	}
+	static $callback;
+	($callback === null) && ($callback = create_function('$match', 'return "&#" . base_convert($match[1], 16, 10) . ";";'));
 	if ( $preview ) // preview fix for javascript bug with foreign languages
-		$output =	preg_replace_callback('/\%u([0-9A-F]{4})/', create_function('$match', 'return "&#" . base_convert($match[1], 16, 10) . ";";'), $output);
+		$output =	preg_replace_callback('/\%u([0-9A-F]{4})/', $callback, $output);
 
 	return $output;
 }