diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 07fbcf4520cc..d316b744e037 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2009-11-18  Richard Guenther  <rguenther@suse.de>
+
+	* lto-streamer-in.c (input_gimple_stmt): Assert that we find
+	a valid field decl if checking is enabled.
+
 2009-11-18  Martin Jambor  <mjambor@suse.cz>
 
 	* ipa-prop.h (struct ipa_param_call_note): New field lto_stmt_uid.
diff --git a/gcc/lto-streamer-in.c b/gcc/lto-streamer-in.c
index dcc92fde13d5..751e70472e4d 100644
--- a/gcc/lto-streamer-in.c
+++ b/gcc/lto-streamer-in.c
@@ -1090,7 +1090,11 @@ input_gimple_stmt (struct lto_input_block *ib, struct data_in *data_in,
 		    }
 		  /* In case of type mismatches across units we can fail
 		     to unify some types and thus not find a proper
-		     field-decl here.  Just do nothing in this case.  */
+		     field-decl here.  So only assert here if checking
+		     is enabled.  */
+#ifdef ENABLE_CHECKING
+		  gcc_assert (tem != NULL_TREE);
+#endif
 		  if (tem != NULL_TREE)
 		    TREE_OPERAND (op, 1) = tem;
 		}