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* [Bug libstdc++/111511] New: Incorrect ADL in std::to_array in GCC 11/12/13
@ 2023-09-21 6:17 de34 at live dot cn
2023-09-21 8:03 ` [Bug libstdc++/111511] " redi at gcc dot gnu.org
` (9 more replies)
0 siblings, 10 replies; 11+ messages in thread
From: de34 at live dot cn @ 2023-09-21 6:17 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111511
Bug ID: 111511
Summary: Incorrect ADL in std::to_array in GCC 11/12/13
Product: gcc
Version: 13.2.1
Status: UNCONFIRMED
Keywords: rejects-valid
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: de34 at live dot cn
Target Milestone: ---
The following program is incorrectly rejected when using libstdc++
(https://godbolt.org/z/x6K6r5svM).
```
#include <array>
#include <utility>
struct incomplete;
template<class T>
struct holder {
T t;
};
using validator = holder<incomplete>*;
int main()
{
validator a[1]{};
(void) std::to_array(a);
(void) std::to_array(std::move(a));
}
```
The error is caused by aunqualified calls to the `__to_array` internal
function, which triggers ADL for `incomplete` and requires it to be complete.
Not sure whether this should be WONTFIX since the implementation is
fundamentally changed in GCC 14 (PR 110167).
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug libstdc++/111511] Incorrect ADL in std::to_array in GCC 11/12/13
2023-09-21 6:17 [Bug libstdc++/111511] New: Incorrect ADL in std::to_array in GCC 11/12/13 de34 at live dot cn
@ 2023-09-21 8:03 ` redi at gcc dot gnu.org
2023-09-21 10:33 ` m.cencora at gmail dot com
` (8 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: redi at gcc dot gnu.org @ 2023-09-21 8:03 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111511
Jonathan Wakely <redi at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |ASSIGNED
Last reconfirmed| |2023-09-21
Ever confirmed|0 |1
Assignee|unassigned at gcc dot gnu.org |redi at gcc dot gnu.org
--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Jiang An from comment #0)
> Not sure whether this should be WONTFIX since the implementation is
> fundamentally changed in GCC 14 (PR 110167).
There's no reason we can't fix the old version in the release branches.
I did notice this when rewriting it, but I didn't think to change the branches
to avoid ADL there, because I plan to backport the new implementation
eventually anyway.
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug libstdc++/111511] Incorrect ADL in std::to_array in GCC 11/12/13
2023-09-21 6:17 [Bug libstdc++/111511] New: Incorrect ADL in std::to_array in GCC 11/12/13 de34 at live dot cn
2023-09-21 8:03 ` [Bug libstdc++/111511] " redi at gcc dot gnu.org
@ 2023-09-21 10:33 ` m.cencora at gmail dot com
2023-09-21 10:42 ` redi at gcc dot gnu.org
` (7 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: m.cencora at gmail dot com @ 2023-09-21 10:33 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111511
m.cencora at gmail dot com changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |m.cencora at gmail dot com
--- Comment #2 from m.cencora at gmail dot com ---
(In reply to Jonathan Wakely from comment #1)
> (In reply to Jiang An from comment #0)
> > Not sure whether this should be WONTFIX since the implementation is
> > fundamentally changed in GCC 14 (PR 110167).
>
> There's no reason we can't fix the old version in the release branches.
>
> I did notice this when rewriting it, but I didn't think to change the
> branches to avoid ADL there, because I plan to backport the new
> implementation eventually anyway.
On a semi-related topic:
Can't we use __builtin_bit_cast as even simpler implementation of to_array for
trivial types?
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug libstdc++/111511] Incorrect ADL in std::to_array in GCC 11/12/13
2023-09-21 6:17 [Bug libstdc++/111511] New: Incorrect ADL in std::to_array in GCC 11/12/13 de34 at live dot cn
2023-09-21 8:03 ` [Bug libstdc++/111511] " redi at gcc dot gnu.org
2023-09-21 10:33 ` m.cencora at gmail dot com
@ 2023-09-21 10:42 ` redi at gcc dot gnu.org
2023-09-21 10:45 ` m.cencora at gmail dot com
` (6 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: redi at gcc dot gnu.org @ 2023-09-21 10:42 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111511
--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Until all supported compilers implement it, that won't be simpler. We'll still
need the memcpy version as a fallback.
And it probably generated exactly the same code, although I haven't checked.
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug libstdc++/111511] Incorrect ADL in std::to_array in GCC 11/12/13
2023-09-21 6:17 [Bug libstdc++/111511] New: Incorrect ADL in std::to_array in GCC 11/12/13 de34 at live dot cn
` (2 preceding siblings ...)
2023-09-21 10:42 ` redi at gcc dot gnu.org
@ 2023-09-21 10:45 ` m.cencora at gmail dot com
2023-09-21 11:37 ` de34 at live dot cn
` (5 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: m.cencora at gmail dot com @ 2023-09-21 10:45 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111511
--- Comment #4 from m.cencora at gmail dot com ---
Ack
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug libstdc++/111511] Incorrect ADL in std::to_array in GCC 11/12/13
2023-09-21 6:17 [Bug libstdc++/111511] New: Incorrect ADL in std::to_array in GCC 11/12/13 de34 at live dot cn
` (3 preceding siblings ...)
2023-09-21 10:45 ` m.cencora at gmail dot com
@ 2023-09-21 11:37 ` de34 at live dot cn
2023-09-25 8:53 ` cvs-commit at gcc dot gnu.org
` (4 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: de34 at live dot cn @ 2023-09-21 11:37 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111511
--- Comment #5 from Jiang An <de34 at live dot cn> ---
(In reply to m.cencora from comment #2)
> (In reply to Jonathan Wakely from comment #1)
> > (In reply to Jiang An from comment #0)
> > > Not sure whether this should be WONTFIX since the implementation is
> > > fundamentally changed in GCC 14 (PR 110167).
> >
> > There's no reason we can't fix the old version in the release branches.
> >
> > I did notice this when rewriting it, but I didn't think to change the
> > branches to avoid ADL there, because I plan to backport the new
> > implementation eventually anyway.
>
> On a semi-related topic:
> Can't we use __builtin_bit_cast as even simpler implementation of to_array
> for trivial types?
__builtin_bit_cast results in constant evaluation failure when the element type
is or contains a pointer or a union, which heavily restricts its usability in
to_array.
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug libstdc++/111511] Incorrect ADL in std::to_array in GCC 11/12/13
2023-09-21 6:17 [Bug libstdc++/111511] New: Incorrect ADL in std::to_array in GCC 11/12/13 de34 at live dot cn
` (4 preceding siblings ...)
2023-09-21 11:37 ` de34 at live dot cn
@ 2023-09-25 8:53 ` cvs-commit at gcc dot gnu.org
2023-09-26 20:15 ` cvs-commit at gcc dot gnu.org
` (3 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2023-09-25 8:53 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111511
--- Comment #6 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jonathan Wakely <redi@gcc.gnu.org>:
https://gcc.gnu.org/g:77cf3773021b0a20d89623e09d620747a05588ec
commit r14-4252-g77cf3773021b0a20d89623e09d620747a05588ec
Author: Jonathan Wakely <jwakely@redhat.com>
Date: Thu Sep 21 09:14:57 2023 +0100
libstdc++: Prevent unwanted ADL in std::to_array [PR111512]
As noted in PR c++/111512, GCC does ADL for __builtin_memcpy if it is
unqualified, which can cause errors for template argument types which
cannot be completed.
Casting the memcpy arguments to void* prevents ADL from considering the
problem type.
libstdc++-v3/ChangeLog:
PR libstdc++/111511
PR c++/111512
* include/std/array (to_array): Cast memcpy arguments to void*.
* testsuite/23_containers/array/creation/111512.cc: New test.
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug libstdc++/111511] Incorrect ADL in std::to_array in GCC 11/12/13
2023-09-21 6:17 [Bug libstdc++/111511] New: Incorrect ADL in std::to_array in GCC 11/12/13 de34 at live dot cn
` (5 preceding siblings ...)
2023-09-25 8:53 ` cvs-commit at gcc dot gnu.org
@ 2023-09-26 20:15 ` cvs-commit at gcc dot gnu.org
2023-09-26 22:55 ` cvs-commit at gcc dot gnu.org
` (2 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2023-09-26 20:15 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111511
--- Comment #7 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-13 branch has been updated by Jonathan Wakely
<redi@gcc.gnu.org>:
https://gcc.gnu.org/g:161a477f0ce93de1d083d379247d0770d4ef96af
commit r13-7844-g161a477f0ce93de1d083d379247d0770d4ef96af
Author: Jonathan Wakely <jwakely@redhat.com>
Date: Thu Sep 21 09:14:57 2023 +0100
libstdc++: Prevent unwanted ADL in std::to_array [PR111512]
Qualify the calls to the __to_array helper to prevent ADL, so we don't
try to complete associated classes.
libstdc++-v3/ChangeLog:
PR libstdc++/111511
PR c++/111512
* include/std/array (to_array): Qualify calls to __to_array.
* testsuite/23_containers/array/creation/111512.cc: New test.
(cherry picked from commit 77cf3773021b0a20d89623e09d620747a05588ec)
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug libstdc++/111511] Incorrect ADL in std::to_array in GCC 11/12/13
2023-09-21 6:17 [Bug libstdc++/111511] New: Incorrect ADL in std::to_array in GCC 11/12/13 de34 at live dot cn
` (6 preceding siblings ...)
2023-09-26 20:15 ` cvs-commit at gcc dot gnu.org
@ 2023-09-26 22:55 ` cvs-commit at gcc dot gnu.org
2023-09-27 16:21 ` cvs-commit at gcc dot gnu.org
2023-09-27 16:23 ` redi at gcc dot gnu.org
9 siblings, 0 replies; 11+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2023-09-26 22:55 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111511
--- Comment #8 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-12 branch has been updated by Jonathan Wakely
<redi@gcc.gnu.org>:
https://gcc.gnu.org/g:685a8c45d8e2c8c10171e672888484ea2c50662e
commit r12-9894-g685a8c45d8e2c8c10171e672888484ea2c50662e
Author: Jonathan Wakely <jwakely@redhat.com>
Date: Thu Sep 21 09:14:57 2023 +0100
libstdc++: Prevent unwanted ADL in std::to_array [PR111512]
Qualify the calls to the __to_array helper to prevent ADL, so we don't
try to complete associated classes.
libstdc++-v3/ChangeLog:
PR libstdc++/111511
PR c++/111512
* include/std/array (to_array): Qualify calls to __to_array.
* testsuite/23_containers/array/creation/111512.cc: New test.
(cherry picked from commit 77cf3773021b0a20d89623e09d620747a05588ec)
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug libstdc++/111511] Incorrect ADL in std::to_array in GCC 11/12/13
2023-09-21 6:17 [Bug libstdc++/111511] New: Incorrect ADL in std::to_array in GCC 11/12/13 de34 at live dot cn
` (7 preceding siblings ...)
2023-09-26 22:55 ` cvs-commit at gcc dot gnu.org
@ 2023-09-27 16:21 ` cvs-commit at gcc dot gnu.org
2023-09-27 16:23 ` redi at gcc dot gnu.org
9 siblings, 0 replies; 11+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2023-09-27 16:21 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111511
--- Comment #9 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-11 branch has been updated by Jonathan Wakely
<redi@gcc.gnu.org>:
https://gcc.gnu.org/g:97a33ab114187e7c6cd6c6c0f06cd8225e8aeef5
commit r11-11021-g97a33ab114187e7c6cd6c6c0f06cd8225e8aeef5
Author: Jonathan Wakely <jwakely@redhat.com>
Date: Thu Sep 21 09:14:57 2023 +0100
libstdc++: Prevent unwanted ADL in std::to_array [PR111512]
Qualify the calls to the __to_array helper to prevent ADL, so we don't
try to complete associated classes.
libstdc++-v3/ChangeLog:
PR libstdc++/111511
PR c++/111512
* include/std/array (to_array): Qualify calls to __to_array.
* testsuite/23_containers/array/creation/111512.cc: New test.
(cherry picked from commit 77cf3773021b0a20d89623e09d620747a05588ec)
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug libstdc++/111511] Incorrect ADL in std::to_array in GCC 11/12/13
2023-09-21 6:17 [Bug libstdc++/111511] New: Incorrect ADL in std::to_array in GCC 11/12/13 de34 at live dot cn
` (8 preceding siblings ...)
2023-09-27 16:21 ` cvs-commit at gcc dot gnu.org
@ 2023-09-27 16:23 ` redi at gcc dot gnu.org
9 siblings, 0 replies; 11+ messages in thread
From: redi at gcc dot gnu.org @ 2023-09-27 16:23 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111511
Jonathan Wakely <redi at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|--- |FIXED
Status|ASSIGNED |RESOLVED
Target Milestone|--- |13.3
--- Comment #10 from Jonathan Wakely <redi at gcc dot gnu.org> ---
std::to_array is fixed on all branches, thanks for the reports.
^ permalink raw reply [flat|nested] 11+ messages in thread
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2023-09-21 8:03 ` [Bug libstdc++/111511] " redi at gcc dot gnu.org
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