Index: gcc/gimple.c
===================================================================
--- gcc/gimple.c	(revision 161714)
+++ gcc/gimple.c	(working copy)
@@ -1731,7 +1731,10 @@
 }
 
 
-/* Return the body of GIMPLE statements for function FN.  */
+/* Return the body of GIMPLE statements for function FN.  After the
+   CFG pass, the function body doesn't exist anymore because it has
+   been splitted up into basic blocks.  In this case, it returns
+   NULL.  */