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* [Bug libstdc++/115480] New: Difference between trivial copyability of std::pair under Clang in C++23
@ 2024-06-13 18:09 ldionne.2 at gmail dot com
2024-06-13 18:15 ` [Bug c++/115480] " pinskia at gcc dot gnu.org
` (5 more replies)
0 siblings, 6 replies; 7+ messages in thread
From: ldionne.2 at gmail dot com @ 2024-06-13 18:09 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115480
Bug ID: 115480
Summary: Difference between trivial copyability of std::pair
under Clang in C++23
Product: gcc
Version: 15.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: ldionne.2 at gmail dot com
Target Milestone: ---
Let's say Foo is a trivially copyable type without an assignment operator.
In C++23, std::pair<Foo, int> is currently trivially copyable using Clang trunk
and GCC trunk. However, it wasn't trivially copyable in the Clang 15 era.
Godbolt: https://godbolt.org/z/TKK7qhhbM
I don't know whether y'all care about this, but we ran into this while
investigating some libc++ stuff and we thought we'd point it out in case it was
considered an ABI break introduced ~2 years ago.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/115480] Difference between trivial copyability of std::pair under Clang in C++23
2024-06-13 18:09 [Bug libstdc++/115480] New: Difference between trivial copyability of std::pair under Clang in C++23 ldionne.2 at gmail dot com
@ 2024-06-13 18:15 ` pinskia at gcc dot gnu.org
2024-06-13 18:20 ` pinskia at gcc dot gnu.org
` (4 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: pinskia at gcc dot gnu.org @ 2024-06-13 18:15 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115480
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
template<typename _Tp>
struct is_trivially_copyable
: public integral_constant<bool, __is_trivially_copyable(_Tp)>
Well it is clang front-end issue though it looks like GCC had a similar issue
too.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/115480] Difference between trivial copyability of std::pair under Clang in C++23
2024-06-13 18:09 [Bug libstdc++/115480] New: Difference between trivial copyability of std::pair under Clang in C++23 ldionne.2 at gmail dot com
2024-06-13 18:15 ` [Bug c++/115480] " pinskia at gcc dot gnu.org
@ 2024-06-13 18:20 ` pinskia at gcc dot gnu.org
2024-06-13 18:24 ` pinskia at gcc dot gnu.org
` (3 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: pinskia at gcc dot gnu.org @ 2024-06-13 18:20 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115480
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
#include <type_traits>
#include <utility>
struct trivially_copyable_no_assignment {
int arr[4];
trivially_copyable_no_assignment& operator=(const
trivially_copyable_no_assignment&) = delete;
};
static_assert(std::is_trivially_copyable<std::pair<trivially_copyable_no_assignment,
int> >::value, "");
int main() { }
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/115480] Difference between trivial copyability of std::pair under Clang in C++23
2024-06-13 18:09 [Bug libstdc++/115480] New: Difference between trivial copyability of std::pair under Clang in C++23 ldionne.2 at gmail dot com
2024-06-13 18:15 ` [Bug c++/115480] " pinskia at gcc dot gnu.org
2024-06-13 18:20 ` pinskia at gcc dot gnu.org
@ 2024-06-13 18:24 ` pinskia at gcc dot gnu.org
2024-06-13 18:28 ` pinskia at gcc dot gnu.org
` (2 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: pinskia at gcc dot gnu.org @ 2024-06-13 18:24 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115480
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|--- |WONTFIX
Status|UNCONFIRMED |RESOLVED
--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Since this is a front-end issue for clang there is not much GCC/libstdc++
cannot do. Plus GCC 12.3 contained the fix that happened to be a bug in GCC 12
series so closing as won't fix.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/115480] Difference between trivial copyability of std::pair under Clang in C++23
2024-06-13 18:09 [Bug libstdc++/115480] New: Difference between trivial copyability of std::pair under Clang in C++23 ldionne.2 at gmail dot com
` (2 preceding siblings ...)
2024-06-13 18:24 ` pinskia at gcc dot gnu.org
@ 2024-06-13 18:28 ` pinskia at gcc dot gnu.org
2024-06-13 18:30 ` pinskia at gcc dot gnu.org
2024-06-14 15:35 ` redi at gcc dot gnu.org
5 siblings, 0 replies; 7+ messages in thread
From: pinskia at gcc dot gnu.org @ 2024-06-13 18:28 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115480
--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Note the change for GCC 12.3.0 that fix it was r12-8799-gaeba3e009b0abf .
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/115480] Difference between trivial copyability of std::pair under Clang in C++23
2024-06-13 18:09 [Bug libstdc++/115480] New: Difference between trivial copyability of std::pair under Clang in C++23 ldionne.2 at gmail dot com
` (3 preceding siblings ...)
2024-06-13 18:28 ` pinskia at gcc dot gnu.org
@ 2024-06-13 18:30 ` pinskia at gcc dot gnu.org
2024-06-14 15:35 ` redi at gcc dot gnu.org
5 siblings, 0 replies; 7+ messages in thread
From: pinskia at gcc dot gnu.org @ 2024-06-13 18:30 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115480
--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #4)
> Note the change for GCC 12.3.0 that fix it was r12-8799-gaeba3e009b0abf .
https://gcc.gnu.org/pipermail/gcc-patches/2022-September/602548.html
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/115480] Difference between trivial copyability of std::pair under Clang in C++23
2024-06-13 18:09 [Bug libstdc++/115480] New: Difference between trivial copyability of std::pair under Clang in C++23 ldionne.2 at gmail dot com
` (4 preceding siblings ...)
2024-06-13 18:30 ` pinskia at gcc dot gnu.org
@ 2024-06-14 15:35 ` redi at gcc dot gnu.org
5 siblings, 0 replies; 7+ messages in thread
From: redi at gcc dot gnu.org @ 2024-06-14 15:35 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115480
--- Comment #6 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Louis Dionne from comment #0)
> we thought we'd point it out in case it
> was considered an ABI break introduced ~2 years ago.
Thanks! It looks like this changed the ABI in C++20 mode, making it consistent
with the ABI in C++17 mode ... which is good (the other way around would be
more concerning). And C++20 mode isn't considered stable, so a change that only
affects C++20 mode isn't something we're going to worry about.
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2024-06-14 15:35 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
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2024-06-13 18:09 [Bug libstdc++/115480] New: Difference between trivial copyability of std::pair under Clang in C++23 ldionne.2 at gmail dot com
2024-06-13 18:15 ` [Bug c++/115480] " pinskia at gcc dot gnu.org
2024-06-13 18:20 ` pinskia at gcc dot gnu.org
2024-06-13 18:24 ` pinskia at gcc dot gnu.org
2024-06-13 18:28 ` pinskia at gcc dot gnu.org
2024-06-13 18:30 ` pinskia at gcc dot gnu.org
2024-06-14 15:35 ` redi at gcc dot gnu.org
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