[Bug tree-optimization/102958] std::u8string suboptimal compared to std::string, triggers warnings

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102958

--- Comment #1 from Martin Sebor <msebor at gcc dot gnu.org> ---
Something similar afflicts
libstdc++-v3/testsuite/21_strings/basic_string/capacity/1.cc but that test is
too contrived to matter in practice.