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* [Bug c++/115233] New: constexpr RVO result is not determined as constant epression
@ 2024-05-26 12:16 konstantin.vladimirov at gmail dot com
2024-05-26 12:18 ` [Bug c++/115233] " pinskia at gcc dot gnu.org
2024-05-26 12:20 ` pinskia at gcc dot gnu.org
0 siblings, 2 replies; 3+ messages in thread
From: konstantin.vladimirov at gmail dot com @ 2024-05-26 12:16 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115233
Bug ID: 115233
Summary: constexpr RVO result is not determined as constant
epression
Product: gcc
Version: 14.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: konstantin.vladimirov at gmail dot com
Target Milestone: ---
Consider I have this type:
---
struct Type {
int a;
const int& b;
constexpr Type() : a(1), b(a) {}
};
constexpr Type t1;
constexpr int c11 = t1.a;
constexpr int c12 = t1.b;
---
c11 and c12 are fine for both gcc and clang
Now lets introduce constexpr function which is subject to RVO:
constexpr auto get() {
return Type();
}
Now try this:
constexpr Type t2 = get();
constexpr int c2 = t2.a;
This code compiles fine with clang but not with gcc.
Live example on godbolt: https://godbolt.org/z/zf3YvebbG
According to [expr.const] and [class.copy.elision] result of constexpr function
is necessary RVO and is contant expression, so t2 construction is fine and t2.a
is constant expression as well.
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug c++/115233] constexpr RVO result is not determined as constant epression
2024-05-26 12:16 [Bug c++/115233] New: constexpr RVO result is not determined as constant epression konstantin.vladimirov at gmail dot com
@ 2024-05-26 12:18 ` pinskia at gcc dot gnu.org
2024-05-26 12:20 ` pinskia at gcc dot gnu.org
1 sibling, 0 replies; 3+ messages in thread
From: pinskia at gcc dot gnu.org @ 2024-05-26 12:18 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115233
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
It also compiles fine with MSVC.
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug c++/115233] constexpr RVO result is not determined as constant epression
2024-05-26 12:16 [Bug c++/115233] New: constexpr RVO result is not determined as constant epression konstantin.vladimirov at gmail dot com
2024-05-26 12:18 ` [Bug c++/115233] " pinskia at gcc dot gnu.org
@ 2024-05-26 12:20 ` pinskia at gcc dot gnu.org
1 sibling, 0 replies; 3+ messages in thread
From: pinskia at gcc dot gnu.org @ 2024-05-26 12:20 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115233
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed| |2024-05-26
Status|UNCONFIRMED |NEW
Ever confirmed|0 |1
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed.
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2024-05-26 12:20 UTC | newest]
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2024-05-26 12:16 [Bug c++/115233] New: constexpr RVO result is not determined as constant epression konstantin.vladimirov at gmail dot com
2024-05-26 12:18 ` [Bug c++/115233] " pinskia at gcc dot gnu.org
2024-05-26 12:20 ` pinskia at gcc dot gnu.org
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