https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93059
--- Comment #9 from fdlbxtqi <euloanty at live dot com> --- (In reply to Marc Glisse from comment #8) > (In reply to fdlbxtqi from comment #6) > > void copy_char_vector_with_iter(std::vector<char8_t>::iterator > > out,std::vector<char> const& bits) > > { > > std::copy_n(bits.begin(),bits.size(),out); > > } > > > > https://godbolt.org/z/_yA_Ls > > See the assembly > > Thanks, I just filed PR 93063 about a subpart that the compiler should be > able to do without help from the library. I have tried the same benchmark on clang. It has the same issue. However, GCC's optimization of this would inspire Clang I believe.