https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105907
--- Comment #1 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jonathan Wakely <r...@gcc.gnu.org>: https://gcc.gnu.org/g:b370ed0bf93ecf0ff51d29e7fc132c433b2aa1be commit r13-1037-gb370ed0bf93ecf0ff51d29e7fc132c433b2aa1be Author: Jonathan Wakely <jwak...@redhat.com> Date: Thu Jun 9 12:07:15 2022 +0100 libstdc++: Make std::hash<basic_string<>> allocator-agnostic (LWG 3705) This new library issue was recently moved to Tentatively Ready by an LWG poll, so I'm making the change on trunk. As noted in PR libstc++/105907 the std::hash specializations for PMR strings were not treated as slow hashes by the unordered containers, so this change preserves that. The new specializations for custom allocators are also not treated as slow, for the same reason. For the versioned namespace (i.e. unstable ABI) we don't have to worry about that, so can enable hash code caching for all basic_string specializations. libstdc++-v3/ChangeLog: * include/bits/basic_string.h (__hash_str_base): New class template. (hash<basic_string<C, char_traits<C>, A>>): Define partial specialization for each of the standard character types. (hash<string>, hash<wstring>, hash<u8string>, hash<u16string>) (hash<u32string>): Remove explicit specializations. * include/std/string (__hash_string_base): Remove class template. (hash<pmr::string>, hash<pmr::wstring>, hash<pmr::u8string>) (hash<pmr::u16string>, hash<pmr::u32string>): Remove explicit specializations. * testsuite/21_strings/basic_string/hash/hash.cc: Test with custom allocators. * testsuite/21_strings/basic_string/hash/hash_char8_t.cc: Likewise.
