[Bug ada/112461] New: [14 regression] Simple return inside extended return loses updates to return object value

[Bug ada/112461] New: [14 regression] Simple return inside extended return loses updates to return object value

[simon at pushface dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112461

            Bug ID: 112461
           Summary: [14 regression] Simple return inside extended return
                    loses updates to return object value
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: ada
          Assignee: unassigned at gcc dot gnu.org
          Reporter: simon at pushface dot org
                CC: dkm at gcc dot gnu.org
  Target Milestone: ---

In a complicated extended return[1] with this structure

   --  Calculate the sum of the natural numbers up to & including the
   --  given limit.
   function Add (Up_To : Natural) return Natural is
      Round : Natural := 0;
   begin
      return Result : Natural := 0 do
         loop
            Result := Result + Round;
            if Round = Up_To then
               return;
            end if;
            Round := Round + 1;
         end loop;
      end return;
   end Add;

what was returned was the equivalent of the initial value (here, 0) rather 
than the value as updated in the loop (NB! this simple loop doesn’t fail, 
I only include it as an example, since I don’t have a simple reproducer).

The problem was introduced after 20231008.

[1]
https://github.com/alire-project/alire/blob/a69ac7c7a24590bdfe1ca77bcb60386551989696/src/alire/alire-properties-from_toml.adb#L14

[Bug ada/112461] [14 regression] Simple return inside extended return loses updates to return object value

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112461

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |14.0

[Bug ada/112461] [14 regression] premature finalization with nested return inside extended one

[ebotcazou at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112461

Eric Botcazou <ebotcazou at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[14 regression] Simple      |[14 regression] premature
                   |return inside extended      |finalization with nested
                   |return loses updates to     |return inside extended one
                   |return object value         |
     Ever confirmed|0                           |1
                 CC|                            |ebotcazou at gcc dot gnu.org
   Last reconfirmed|                            |2023-11-10
             Status|UNCONFIRMED                 |NEW

--- Comment #1 from Eric Botcazou <ebotcazou at gcc dot gnu.org> ---
Yes, by commit 2e135bdb28d386b0cda2ee7e35338ad06136042d, but the issue was
preexisting if the return type is limited.  The fix is upcoming.

[Bug ada/112461] [14 regression] premature finalization with nested return inside extended one

[ebotcazou at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112461

Eric Botcazou <ebotcazou at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
           Assignee|unassigned at gcc dot gnu.org      |ebotcazou at gcc dot gnu.org

[Bug ada/112461] [14 regression] premature finalization with nested return inside extended one

[ebotcazou at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112461

Eric Botcazou <ebotcazou at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
             Status|ASSIGNED                    |RESOLVED

--- Comment #2 from Eric Botcazou <ebotcazou at gcc dot gnu.org> ---
https://gcc.gnu.org/g:f6bbf84ec759f203251c6c5a0dec8344f17cc614

commit r14-5909-gf6bbf84ec759f203251c6c5a0dec8344f17cc614
Author: Eric Botcazou <ebotcazou@adacore.com>
Date:   Wed Nov 8 23:29:01 2023 +0100

    ada: Fix premature finalization for nested return within extended one

    The return object is incorrectly finalized when the nested return is taken,
    because the special flag attached to the return object is not updated.

    gcc/ada/
            * exp_ch6.adb (Build_Flag_For_Function): New function made up of
the
            code building the special flag for return object present...
            (Expand_N_Extended_Return_Statement): ...in there.  Replace the
code
            with a call to Build_Flag_For_Function.  Add assertion for the
flag.
            (Expand_Non_Function_Return): For a nested return, if the return
            object needs finalization actions, update the special flag.