diff --git a/gcc/ada/exp_aggr.adb b/gcc/ada/exp_aggr.adb
index c63d22b58fa..1cfc97b5bc6 100644
--- a/gcc/ada/exp_aggr.adb
+++ b/gcc/ada/exp_aggr.adb
@@ -4509,6 +4509,11 @@ package body Exp_Aggr is
             return False;
          end if;
 
+         if not (UI_Is_In_Int_Range (Lov) and UI_Is_In_Int_Range (Hiv)) then
+            --  guard against raising C_E in UI_To_Int
+            return False;
+         end if;
+
          --  Determine if set of alternatives is suitable for conversion and
          --  build an array containing the values in sequence.