https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120577
Bug ID: 120577
Summary: Another crash with [[no_unique_address]] and constexpr
functions
Product: gcc
Version: 15.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: nikolasklauser at berlin dot de
Target Milestone: ---
```
template <class _Tp> struct optional {
union {
_Tp __val_;
};
template <class... _Args>
constexpr optional(_Args... __args)
: __val_(__args...) {}
};
template <class _Tp, class... _Args>
constexpr optional<_Tp> make_optional(_Args... __args) {
return optional<_Tp>(__args...);
}
struct __non_trivial_if {
constexpr __non_trivial_if() {}
};
struct allocator : __non_trivial_if {};
struct __padding {};
struct __short {
[[__no_unique_address__]] __padding __padding_;
int __data_;
};
struct basic_string {
union {
__short __s;
};
[[__no_unique_address__]] allocator __alloc_;
constexpr basic_string(int, int) {}
};
auto opt = make_optional<basic_string>(4, 'X');
```
This is another crash similar to
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120502. I'm pretty sure it's
distinct though. I've applied the other patch locally and that fixed the bug,
but this reproducer still crashes.
This time `g++ -std=c++26 <file>` is enough to reproduce.
