Index: loader_tags.py
===================================================================
--- loader_tags.py	(revision 7028)
+++ loader_tags.py	(working copy)
@@ -41,6 +41,10 @@
         self.nodelist = nodelist
         self.parent_name, self.parent_name_expr = parent_name, parent_name_expr
         self.template_dirs = template_dirs
+        if parent_name:
+            self.compiled_parent = self.get_parent(None)
+        else:
+            self.compiled_parent = None
 
     def get_parent(self, context):
         if self.parent_name_expr:
@@ -61,7 +65,10 @@
             return get_template_from_string(source, origin, parent)
 
     def render(self, context):
-        compiled_parent = self.get_parent(context)
+        if self.compiled_parent:
+            compiled_parent = self.compiled_parent
+        else:
+            compiled_parent = self.get_parent(context)
         parent_is_child = isinstance(compiled_parent.nodelist[0], ExtendsNode)
         parent_blocks = dict([(n.name, n) for n in compiled_parent.nodelist.get_nodes_by_type(BlockNode)])
         for block_node in self.nodelist.get_nodes_by_type(BlockNode):