https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110945
--- Comment #2 from Jan Schultke <janschultke at googlemail dot com> --- Also it looks like GCC doesn't emit memcpy or memmove in either of the first benchmarks. Those statements refer to the corresponding clang output, actually. What's consistent for both compilers is that .assign() is dramatically slower than any other method.