[gcc r12-1624] [Ada] Correct A'First (N) where N is an object name

[Pierre-Marie de Rodat <pmderodat@gcc.gnu.org>]

https://gcc.gnu.org/g:537f0ce3078e4b1dd9f357ed4ed791e05024455a

commit r12-1624-g537f0ce3078e4b1dd9f357ed4ed791e05024455a
Author: Bob Duff <duff@adacore.com>
Date:   Wed Mar 17 12:14:12 2021 -0400

    [Ada] Correct A'First (N) where N is an object name
    
    gcc/ada/
    
            * sem_attr.adb (Check_Array_Or_Scalar_Type): Use Expr_Value
            instead of Intval, because the latter only exists in literals.
            Remove Set_Etype on E1; setting the type is done elsewhere.

Diff:
---
 gcc/ada/sem_attr.adb | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/gcc/ada/sem_attr.adb b/gcc/ada/sem_attr.adb
index 63b0f09ea5d..f9b17c75d4b 100644
--- a/gcc/ada/sem_attr.adb
+++ b/gcc/ada/sem_attr.adb
@@ -1603,7 +1603,6 @@ package body Sem_Attr is
 
          --  Local variables
 
-         Dims  : Int;
          Index : Entity_Id;
 
       --  Start of processing for Check_Array_Or_Scalar_Type
@@ -1667,14 +1666,16 @@ package body Sem_Attr is
                Set_Etype (N, Base_Type (Etype (Index)));
 
             else
-               Dims := UI_To_Int (Intval (E1));
-
-               for J in 1 .. Dims - 1 loop
-                  Next_Index (Index);
-               end loop;
+               declare
+                  Udims : constant Uint := Expr_Value (E1);
+                  Dims  : constant Int  := UI_To_Int (Udims);
+               begin
+                  for J in 1 .. Dims - 1 loop
+                     Next_Index (Index);
+                  end loop;
+               end;
 
                Set_Etype (N, Base_Type (Etype (Index)));
-               Set_Etype (E1, Standard_Integer);
             end if;
          end if;
       end Check_Array_Or_Scalar_Type;