[Bug c++/108474] New: static structured binding undefined reference

[Bug c++/108474] New: static structured binding undefined reference

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108474

            Bug ID: 108474
           Summary: static structured binding undefined reference
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Keywords: link-failure, wrong-code
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pinskia at gcc dot gnu.org
  Target Milestone: ---

Take this c++20 (-std=c++20):
```
struct t
{
  int i, j;
};
t y;
static auto [i, j] = y;
int &r = i;
int s = i;
int *t = &i;
int main() {}
```

This fails in a similar way as PR 53932 but this is for structued bindings
rather than static anonymous unions.

[Bug c++/108474] static structured binding undefined reference

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108474

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |ice-on-valid-code

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
And yes it ICEs with LTO too.

[Bug c++/108474] static structured binding undefined reference

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108474

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2023-01-20
           Assignee|unassigned at gcc dot gnu.org      |jakub at gcc dot gnu.org
                 CC|                            |jakub at gcc dot gnu.org
             Status|UNCONFIRMED                 |ASSIGNED
     Ever confirmed|0                           |1

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 54315
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=54315&action=edit
gcc13-pr108474.patch

Untested fix.

[Bug c++/108474] static structured binding undefined reference

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108474

--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jakub Jelinek <jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:b84e21115700523b4d0ac44275443f7b9c670344

commit r13-5323-gb84e21115700523b4d0ac44275443f7b9c670344
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Tue Jan 24 11:28:00 2023 +0100

    c++: Handle structured bindings like anon unions in initializers [PR108474]

    As reported by Andrew Pinski, structured bindings (with the exception
    of the ones using std::tuple_{size,element} and get which are really
    standalone variables in addition to the binding one) also use
    DECL_VALUE_EXPR and needs the same treatment in static initializers.

    On Sun, Jan 22, 2023 at 07:19:07PM -0500, Jason Merrill wrote:
    > Though, actually, why not instead fix expand_expr_real_1 (and staticp) to
    > look through DECL_VALUE_EXPR?

    Doing it when emitting the initializers seems to be too late to me,
    we in various spots try to put parts of the static var DECL_INITIAL
expressions
    into the IL, or e.g. for varpool purposes remember which vars are
referenced
    there.

    This patch moves it to record_reference, which is called from
varpool_node::analyze
    and so about the same time as gimplification of the bodies which also
    replaces DECL_VALUE_EXPRs.

    2023-01-24  Jakub Jelinek  <jakub@redhat.com>

            PR c++/108474
            * cgraphbuild.cc: Include gimplify.h.
            (record_reference): Replace VAR_DECLs with DECL_HAS_VALUE_EXPR_P
with
            their corresponding DECL_VALUE_EXPR expressions after unsharing.

            * cp-gimplify.cc (cp_fold_r): Revert 2023-01-19 changes.

            * g++.dg/cpp1z/decomp57.C: New test.
            * g++.dg/cpp1z/decomp58.C: New test.

[Bug c++/108474] static structured binding undefined reference

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108474

--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-12 branch has been updated by Jakub Jelinek
<jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:c153fb6a5bda225fcfb34e17994a31b65616a6db

commit r12-9159-gc153fb6a5bda225fcfb34e17994a31b65616a6db
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Tue Jan 24 11:28:00 2023 +0100

    c++: Handle structured bindings like anon unions in initializers [PR108474]

    As reported by Andrew Pinski, structured bindings (with the exception
    of the ones using std::tuple_{size,element} and get which are really
    standalone variables in addition to the binding one) also use
    DECL_VALUE_EXPR and needs the same treatment in static initializers.

    On Sun, Jan 22, 2023 at 07:19:07PM -0500, Jason Merrill wrote:
    > Though, actually, why not instead fix expand_expr_real_1 (and staticp) to
    > look through DECL_VALUE_EXPR?

    Doing it when emitting the initializers seems to be too late to me,
    we in various spots try to put parts of the static var DECL_INITIAL
expressions
    into the IL, or e.g. for varpool purposes remember which vars are
referenced
    there.

    This patch moves it to record_reference, which is called from
varpool_node::analyze
    and so about the same time as gimplification of the bodies which also
    replaces DECL_VALUE_EXPRs.

    2023-01-24  Jakub Jelinek  <jakub@redhat.com>

            PR c++/108474
            * cp-gimplify.cc (cp_fold_r): Handle structured bindings
            vars like anon union artificial vars.

            * g++.dg/cpp1z/decomp57.C: New test.
            * g++.dg/cpp1z/decomp58.C: New test.

    (cherry picked from commit b84e21115700523b4d0ac44275443f7b9c670344)

[Bug c++/108474] static structured binding undefined reference

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108474

--- Comment #5 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-11 branch has been updated by Jakub Jelinek
<jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:bc75dd303c8f8aa6191670ce3725d26e8011f5ac

commit r11-10712-gbc75dd303c8f8aa6191670ce3725d26e8011f5ac
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Tue Jan 24 11:28:00 2023 +0100

    c++: Handle structured bindings like anon unions in initializers [PR108474]

    As reported by Andrew Pinski, structured bindings (with the exception
    of the ones using std::tuple_{size,element} and get which are really
    standalone variables in addition to the binding one) also use
    DECL_VALUE_EXPR and needs the same treatment in static initializers.

    On Sun, Jan 22, 2023 at 07:19:07PM -0500, Jason Merrill wrote:
    > Though, actually, why not instead fix expand_expr_real_1 (and staticp) to
    > look through DECL_VALUE_EXPR?

    Doing it when emitting the initializers seems to be too late to me,
    we in various spots try to put parts of the static var DECL_INITIAL
expressions
    into the IL, or e.g. for varpool purposes remember which vars are
referenced
    there.

    This patch moves it to record_reference, which is called from
varpool_node::analyze
    and so about the same time as gimplification of the bodies which also
    replaces DECL_VALUE_EXPRs.

    2023-01-24  Jakub Jelinek  <jakub@redhat.com>

            PR c++/108474
            * cp-gimplify.c (cp_fold_r): Handle structured bindings
            vars like anon union artificial vars.

            * g++.dg/cpp1z/decomp57.C: New test.
            * g++.dg/cpp1z/decomp58.C: New test.

    (cherry picked from commit b84e21115700523b4d0ac44275443f7b9c670344)

[Bug c++/108474] static structured binding undefined reference

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108474

--- Comment #6 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-10 branch has been updated by Jakub Jelinek
<jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:8776316329f34ba87cca64622e93c05ff36890bb

commit r10-11366-g8776316329f34ba87cca64622e93c05ff36890bb
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Tue Jan 24 11:28:00 2023 +0100

    c++: Handle structured bindings like anon unions in initializers [PR108474]

    As reported by Andrew Pinski, structured bindings (with the exception
    of the ones using std::tuple_{size,element} and get which are really
    standalone variables in addition to the binding one) also use
    DECL_VALUE_EXPR and needs the same treatment in static initializers.

    On Sun, Jan 22, 2023 at 07:19:07PM -0500, Jason Merrill wrote:
    > Though, actually, why not instead fix expand_expr_real_1 (and staticp) to
    > look through DECL_VALUE_EXPR?

    Doing it when emitting the initializers seems to be too late to me,
    we in various spots try to put parts of the static var DECL_INITIAL
expressions
    into the IL, or e.g. for varpool purposes remember which vars are
referenced
    there.

    This patch moves it to record_reference, which is called from
varpool_node::analyze
    and so about the same time as gimplification of the bodies which also
    replaces DECL_VALUE_EXPRs.

    2023-01-24  Jakub Jelinek  <jakub@redhat.com>

            PR c++/108474
            * cp-gimplify.c (cp_fold_r): Handle structured bindings
            vars like anon union artificial vars.

            * g++.dg/cpp1z/decomp57.C: New test.
            * g++.dg/cpp1z/decomp58.C: New test.

    (cherry picked from commit b84e21115700523b4d0ac44275443f7b9c670344)

[Bug c++/108474] static structured binding undefined reference

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108474

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

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

--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Fixed for 10.5 too.