https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109039
Bug ID: 109039
Summary: Miscompilation with no_unique_address and bitfields
Product: gcc
Version: 12.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: coillol at yandex dot ru
Target Milestone: ---
g++ miscompiles the following code starting from version 12.1 (-std=c++20, any
optimization mode).
```
#include <cassert>
struct X {
short x0 : 7;
short x1 : 8;
X() { init(); assert(get() == 3); }
void init() { x0 = 1; x1 = 2; }
int get() { return x0 + x1; }
};
struct S {
[[no_unique_address]] X x;
char c = 0;
};
int main() {
S s;
assert(s.x.get() == 3);
return 0;
}
```
Program hits assertion in main when executed. Links to godbolt:
https://godbolt.org/z/xG186673P (12.1), https://godbolt.org/z/MaP56rfhe
(trunk).
