[Bug c++/81933] [7/8 Regression] Invalid "constexpr call flows off the end of the function" error

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81933

--- Comment #6 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
And I bet the solution will be to handle empty classes in
split_nonconstant_init_1 or somewhere similar.