diff --git a/gcc/ada/ChangeLog b/gcc/ada/ChangeLog
index dcad0df960a1..5462077b49b3 100644
--- a/gcc/ada/ChangeLog
+++ b/gcc/ada/ChangeLog
@@ -1,3 +1,9 @@
+2013-10-14  Hristian Kirtchev  <kirtchev@adacore.com>
+
+	* sem_prag.adb (Check_Mode): Do not emit an
+	error when inspecting a self referencial output item of an
+	unconstrained type.
+
 2013-10-14  Tristan Gingold  <gingold@adacore.com>
 
 	* exp_prag.adb (Expand_Pragma_Import_Export_Exception): Fix
diff --git a/gcc/ada/sem_prag.adb b/gcc/ada/sem_prag.adb
index 21e476599fcf..fc263c22c3de 100644
--- a/gcc/ada/sem_prag.adb
+++ b/gcc/ada/sem_prag.adb
@@ -928,6 +928,15 @@ package body Sem_Prag is
                   Error_Msg_NE ("item & must have mode in out", Item, Item_Id);
                end if;
 
+            --  A self-referential out parameter of an unconstrained or tagged
+            --  type acts as an input because the discriminants, array bounds
+            --  or the tag may be read.
+
+            elsif Ekind (Item_Id) = E_Out_Parameter
+              and then Is_Unconstrained_Or_Tagged_Item (Item_Id)
+            then
+               null;
+
             --  Self-referential parameter
 
             elsif Ekind (Item_Id) /= E_In_Out_Parameter then