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* [Bug c++/107222] New: const qualifier appears in mangled NTTP value when the original object is so qualified
@ 2022-10-11 19:52 johelegp at gmail dot com
2022-10-11 20:07 ` [Bug c++/107222] " pinskia at gcc dot gnu.org
0 siblings, 1 reply; 2+ messages in thread
From: johelegp at gmail dot com @ 2022-10-11 19:52 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107222
Bug ID: 107222
Summary: const qualifier appears in mangled NTTP value when the
original object is so qualified
Product: gcc
Version: 13.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: johelegp at gmail dot com
CC: johelegp at gmail dot com
Target Milestone: ---
See https://compiler-explorer.com/z/63f9sxnec.
```C++
struct A { int i; };
union Y { A a; };
constexpr Y make_y(const A a) { return {a}; }
template<auto> struct q { };
template<auto V> constexpr q<V> make_q() { return {}; }
template<auto> void print();
int main() {
constexpr q x = make_q<make_y({1})>();
print<x>();
// +x;
}
```
```
main:
sub rsp, 8
call void print<q<Y{.a=A const{1}}>{}>()
xor eax, eax
add rsp, 8
ret
```
Alternatively, when uncommenting `+x;`:
```
<source>: In function 'int main()':
<source>:10:3: error: no match for 'operator+' (operand type is 'const
q<Y{const A{1}}>')
10 | +x;
| ^~
```
^ permalink raw reply [flat|nested] 2+ messages in thread
* [Bug c++/107222] const qualifier appears in mangled NTTP value when the original object is so qualified
2022-10-11 19:52 [Bug c++/107222] New: const qualifier appears in mangled NTTP value when the original object is so qualified johelegp at gmail dot com
@ 2022-10-11 20:07 ` pinskia at gcc dot gnu.org
0 siblings, 0 replies; 2+ messages in thread
From: pinskia at gcc dot gnu.org @ 2022-10-11 20:07 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107222
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Ever confirmed|0 |1
Last reconfirmed| |2022-10-11
Status|UNCONFIRMED |NEW
Keywords| |ABI, wrong-code
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Here is one which shows the issue at link time.
This should link and run.
One testcase:
```
struct A { int i; };
union Y { A a; };
constexpr Y make_y(const A a) { return {a}; }
template<auto> struct q { };
template<auto V> constexpr q<V> make_q() { return {}; }
template<auto> void print();
template<> void print<q<(Y){.a={1}}>{}>()
{
}
int main() {
constexpr q x = make_q<make_y({1})>();
constexpr q x1 = make_q<(Y){.a={1}}>();
print<x>();
print<x1>();
}
```
Another one:
```
struct A { int i; };
union Y { A a; };
constexpr Y make_y(const A a) { return {a}; }
template<auto> struct q { };
template<auto V> constexpr q<V> make_q() { return {}; }
void print(q<(Y){.a={1}}> a)
{
}
void print(...);
int main() {
constexpr q x = make_q<make_y({1})>();
constexpr q x1 = make_q<(Y){.a={1}}>();
print(x);
print(x1);
}
```
clang mangles both x and x1 the same ...
^ permalink raw reply [flat|nested] 2+ messages in thread
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2022-10-11 19:52 [Bug c++/107222] New: const qualifier appears in mangled NTTP value when the original object is so qualified johelegp at gmail dot com
2022-10-11 20:07 ` [Bug c++/107222] " pinskia at gcc dot gnu.org
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