[Bug c++/94175] [10 Regression] Passing constexpr empty class variable to function since r10-599

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94175

--- Comment #1 from Jason Merrill <jason at gcc dot gnu.org> ---
Testcase using fewer C++ features:

struct A {};
extern A a;

int i;
[[gnu::noinline, gnu::noclone]]
void f(A) { ++i; }

int main()
{
  f(a);
}