[Bug libstdc++/81078] dynamic_cast to virtual base produces the wrong answer

[arthur.j.odwyer at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81078

--- Comment #3 from Arthur O'Dwyer <arthur.j.odwyer at gmail dot com> ---
Yes, this is a libstdc++ issue.

I'm not 100% sure that "the RTTI [generated by GCC] is correct," because I
don't know how to use GCC with libc++; but yeah, there's definitely at least
some problem with libstdc++ here. Observe that Clang-with-libstdc++ fails,
Clang-with-libc++ succeeds: https://godbolt.org/z/PMq6rW9cE