[Bug libstdc++/104945] std::hash ignores the top 32 bits when size_t is 32 bit

[redi at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104945

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
This affects anything wider than size_t, including std::hash<__int128> on
64-bit targets.