https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93921
--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to Bjørnar Snoksrud from comment #3) > Using '--std=c++20 -Os' generates minimal code. That disables the explicit template instantiation declarations for std::string, so the compiler performs implicit instantiations and then inlines the code. Without C++20 the compiler sees the explicit instantiation declarations (i.e. the 'extern template' declarations) and emits calls to those external definitions, without inlining anything. I think GCC needs to be better at deciding when to ignore the explicit instantiations and to do implicit instantiations anyway.
