Index: path.inc
===================================================================
--- path.inc	(revision 1522)
+++ path.inc	(working copy)
@@ -216,9 +216,13 @@
  *   Boolean value: TRUE if the current page is the front page; FALSE if otherwise.
  */
 function drupal_is_front_page() {
+  static $front_path;
+  if (!isset($front_path)) {
+    $front_path = drupal_get_normal_path(variable_get('site_frontpage', 'node'));
+  }
   // As drupal_init_path updates $_GET['q'] with the 'site_frontpage' path,
   // we can check it against the 'site_frontpage' variable.
-  return $_GET['q'] == drupal_get_normal_path(variable_get('site_frontpage', 'node'));
+  return $_GET['q'] == $front_path;
 }
 
 /**