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* [Bug c++/101588] New: rejects valid constexpr when binding from a constexpr function
@ 2021-07-23 2:17 pinskia at gcc dot gnu.org
2021-07-23 2:22 ` [Bug c++/101588] rejects valid constexpr when binding from a constexpr function and initializer_list pinskia at gcc dot gnu.org
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-07-23 2:17 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101588
Bug ID: 101588
Summary: rejects valid constexpr when binding from a constexpr
function
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Keywords: rejects-valid
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: pinskia at gcc dot gnu.org
Target Milestone: ---
Split out from PR 66287.
Take:
struct T { int i; };
constexpr T copy(const T& v) { return v; }
constexpr const auto& r = T{42};
constexpr const auto& c = copy(r);
int main() {}
----- CUT ----
This should be accepted by GCC but currently is rejected:
<source>:11:33: error: modification of '<temporary>' is not a constant
expression
11 | constexpr const auto& c = copy(r);
| ^
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/101588] rejects valid constexpr when binding from a constexpr function and initializer_list
2021-07-23 2:17 [Bug c++/101588] New: rejects valid constexpr when binding from a constexpr function pinskia at gcc dot gnu.org
@ 2021-07-23 2:22 ` pinskia at gcc dot gnu.org
2021-07-23 2:34 ` [Bug c++/101588] [DR2126] " pinskia at gcc dot gnu.org
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-07-23 2:22 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101588
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Note clang was only fixed in clang 12.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/101588] [DR2126] rejects valid constexpr when binding from a constexpr function and initializer_list
2021-07-23 2:17 [Bug c++/101588] New: rejects valid constexpr when binding from a constexpr function pinskia at gcc dot gnu.org
2021-07-23 2:22 ` [Bug c++/101588] rejects valid constexpr when binding from a constexpr function and initializer_list pinskia at gcc dot gnu.org
@ 2021-07-23 2:34 ` pinskia at gcc dot gnu.org
2023-02-09 0:23 ` mpolacek at gcc dot gnu.org
2023-02-10 0:07 ` mpolacek at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-07-23 2:34 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101588
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Summary|rejects valid constexpr |[DR2126] rejects valid
|when binding from a |constexpr when binding from
|constexpr function and |a constexpr function and
|initializer_list |initializer_list
Alias| |DR2126
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
GCC implements DR2126 mostly except when the type is intialized like: T{42} .
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/101588] [DR2126] rejects valid constexpr when binding from a constexpr function and initializer_list
2021-07-23 2:17 [Bug c++/101588] New: rejects valid constexpr when binding from a constexpr function pinskia at gcc dot gnu.org
2021-07-23 2:22 ` [Bug c++/101588] rejects valid constexpr when binding from a constexpr function and initializer_list pinskia at gcc dot gnu.org
2021-07-23 2:34 ` [Bug c++/101588] [DR2126] " pinskia at gcc dot gnu.org
@ 2023-02-09 0:23 ` mpolacek at gcc dot gnu.org
2023-02-10 0:07 ` mpolacek at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2023-02-09 0:23 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101588
Marek Polacek <mpolacek at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Ever confirmed|0 |1
Last reconfirmed| |2023-02-09
CC| |mpolacek at gcc dot gnu.org
Status|UNCONFIRMED |NEW
--- Comment #3 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
This came up again in bug 107079. The static_assert should pass after fixing
bug 107079 but doesn't because we don't fully implement the
-- a temporary object of non-volatile const-qualified literal type whose
lifetime is extended ([class.temporary]) to that of a variable that is usable
in constant expressions, or
bullet.
struct X {
const X* x = this;
};
constexpr const X& x = X{};
static_assert(x.x == &x);
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/101588] [DR2126] rejects valid constexpr when binding from a constexpr function and initializer_list
2021-07-23 2:17 [Bug c++/101588] New: rejects valid constexpr when binding from a constexpr function pinskia at gcc dot gnu.org
` (2 preceding siblings ...)
2023-02-09 0:23 ` mpolacek at gcc dot gnu.org
@ 2023-02-10 0:07 ` mpolacek at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2023-02-10 0:07 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101588
--- Comment #4 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
When fixing this, please adjust g++.dg/cpp0x/constexpr-nsdmi2.C.
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2023-02-10 0:07 UTC | newest]
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2021-07-23 2:17 [Bug c++/101588] New: rejects valid constexpr when binding from a constexpr function pinskia at gcc dot gnu.org
2021-07-23 2:22 ` [Bug c++/101588] rejects valid constexpr when binding from a constexpr function and initializer_list pinskia at gcc dot gnu.org
2021-07-23 2:34 ` [Bug c++/101588] [DR2126] " pinskia at gcc dot gnu.org
2023-02-09 0:23 ` mpolacek at gcc dot gnu.org
2023-02-10 0:07 ` mpolacek at gcc dot gnu.org
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