[Ada] Fix PR ada/104258

[Eric Botcazou via Gcc-patches]

This is a regression present on mainline and 11 branch: the new transformation 
applied during expansion by Narrow_Large_Operation would incorrectly perform 
name resolution for the operator again.

Tested on x86_64-suse-linux, applied on mainline and 11 branch.


2022-01-28  Eric Botcazou  <ebotca...@adacore.com>

        PR ada/104258
        * exp_ch4.adb (Narrow_Large_Operation): Also copy the entity, if
        any, when rewriting the operator node.


2022-01-28  Eric Botcazou  <ebotca...@adacore.com>

        * gnat.dg/generic_comp.adb: New test.

-- 
Eric Botcazou
diff --git a/gcc/ada/exp_ch4.adb b/gcc/ada/exp_ch4.adb
index c31f5bb36ba..2506c67e936 100644
--- a/gcc/ada/exp_ch4.adb
+++ b/gcc/ada/exp_ch4.adb
@@ -14314,9 +14314,13 @@ package body Exp_Ch4 is
          return;
       end if;
 
-      --  Finally, rewrite the operation in the narrower type
+      --  Finally, rewrite the operation in the narrower type, but make sure
+      --  not to perform name resolution for the operator again.
 
       Nop := New_Op_Node (Kind, Sloc (N));
+      if Nkind (N) in N_Has_Entity then
+         Set_Entity (Nop, Entity (N));
+      end if;
 
       if Binary then
          Set_Left_Opnd (Nop, Convert_To (Ntyp, L));

-- { dg-do run }

procedure Generic_Comp is

   generic
      type Element_Type is private;
      type Index_Type is (<>);
      type Array_Type is array (Index_Type range <>) of Element_Type;
      with function ">" (Left, Right : Element_Type) return Boolean is <>;
   procedure Gen (Data: in out Array_Type);

   procedure Gen (Data: in out Array_Type) is
   begin
      if not (Data'Length > 1)
        or else not (Integer'(Data'Length) > 1)
        or else not Standard.">" (Data'Length, 1)
        or else not Standard.">" (Integer'(Data'Length), 1)
      then
         raise Program_Error;
      end if;
   end;

   type My_Array is array (Positive range <>) of Integer;

   function Less_Than (L, R : Integer) return Boolean is
   begin
      return L < R;
   end;

   procedure Chk_Down is new Gen (Element_Type => Integer,
                                  Index_Type   => Positive,
                                  Array_Type   => My_Array,
                                  ">"          => Less_Than);

   Data : My_Array (1 .. 2);

begin
   Chk_Down (Data);
end;