[Bug ada/101970] New: [11 regression] ICE on 'Enum_Rep for the enum that filled its representation range

["demoonlit at panathenaia dot halfmoon.jp" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101970

            Bug ID: 101970
           Summary: [11 regression] ICE on 'Enum_Rep for the enum that
                    filled its representation range
           Product: gcc
           Version: 11.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: ada
          Assignee: unassigned at gcc dot gnu.org
          Reporter: demoonlit at panathenaia dot halfmoon.jp
  Target Milestone: ---

Created attachment 51322
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=51322&action=edit
full test code

Perhaps this is a regression by fixing the bug 101094.

'Enum_Rep causes GNAT bug Box, with the enum type containing the number of
elements to fill just its (signed?) representation range.

Thanks.

#### test code ####

Here is the abbreviated test code.
The full code is attached.

with Ada.Integer_Text_IO;
with Ada.Text_IO;
procedure test_enumrep2 is
   type T is (E80, ..., E00, ..., E7F); -- 256 elements
   for T use (E80 => -16#80#, ..., E00 => 16#00#, ..., E7F => 16#7F#); -- -128
to +127
   for T'Size use 8;
   procedure P (X : T);
   pragma No_Inline (P);
   procedure P (X : T) is
   begin
      Ada.Integer_Text_IO.Put (T'Pos (X));
      Ada.Integer_Text_IO.Put (T'Enum_Rep (X)); -- GNAT BUG DETECTED
      Ada.Text_IO.New_Line;
   end P;
begin
   P (T'First);
   P (T'Last);
end test_enumrep2;

#### gcc-10.2.0 ####

% /opt/ytomino/gcc-10.2.0/bin/gnatmake --version
GNATMAKE 10.2.0
Copyright (C) 1995-2020, Free Software Foundation, Inc.
This is free software; see the source for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE.

% /opt/ytomino/gcc-10.2.0/bin/gnatmake test_enumrep2.adb
gcc -c test_enumrep2.adb
gnatbind -x test_enumrep2.ali
gnatlink test_enumrep2.ali

% ./test_enumrep2 
          0       -128
        255        127

It's fine.

#### gcc-11.1.0 ####

% /opt/ytomino/gcc-11.1.0/bin/gnatmake --version
GNATMAKE 11.1.0
Copyright (C) 1995-2021, Free Software Foundation, Inc.
This is free software; see the source for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE.

% /opt/ytomino/gcc-11.1.0/bin/gnatmake test_enumrep2.adb
gcc -c test_enumrep2.adb
gnatbind -x test_enumrep2.ali
gnatlink test_enumrep2.ali
% ./test_enumrep2
          0        128
        255        127

Note, T'Enum_Rep(T'First) returns the unsigned value in gcc-11.1 because bug
101094.

#### gcc-11.2.0 ####

% /opt/ytomino/gcc-11.2.0/bin/gnatmake --version
GNATMAKE 11.2.0
Copyright (C) 1995-2021, Free Software Foundation, Inc.
This is free software; see the source for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE.

% /opt/ytomino/gcc-11.2.0/bin/gnatmake test_enumrep2
gcc -c test_enumrep2.adb
+===========================GNAT BUG DETECTED==============================+
| 11.2.0 (x86_64-linux-gnu) GCC error:                                     |
| in build_binary_op, at ada/gcc-interface/utils2.c:1164                   |
| Error detected at test_enumrep2.adb:107:44                               |
| Please submit a bug report; see https://gcc.gnu.org/bugs/ .              |
| Use a subject line meaningful to you and us to track the bug.            |
| Include the entire contents of this bug box in the report.               |
| Include the exact command that you entered.                              |
| Also include sources listed below.                                       |
+==========================================================================+

Please include these source files with error report
Note that list may not be accurate in some cases,
so please double check that the problem can still
be reproduced with the set of files listed.
Consider also -gnatd.n switch (see debug.adb).

test_enumrep2.adb

compilation abandoned
gnatmake: "test_enumrep2.adb" compilation error