If anyone's curious, here's the link to memcpy() as it's actually implemented in the Cosmopolitan headers: https://github.com/jart/cosmopolitan/blob/de09bec2156

If anyone's curious, here's the link to memcpy() as it's actually implemented in the Cosmopolitan headers: https://github.com/jart/cosmopolitan/blob/de09bec215675e9b0beb722df89c6f794da74f3f/libc/str/str.h#L252 https://github.com/jart/cosmopolitan/blob/de09bec215675e9b0b... One thing that the web page doesn't mention (for the sake of simplicity) is that the Cosmopolitan headers do call __builtin_memcpy() as well, but only for 2-power constexpr sizes. That's the only time when GCC and Clang both do the optimal thing. In all other cases it's faster to use asm("call MemCpy") which implements something faster than the builtin would otherwise generate. See https://github.com/jart/cosmopolitan/blob/de09bec215675e9b0beb722df89c6f794da74f3f/libc/nexgen32e/memcpy.S#L49 https://github.com/jart/cosmopolitan/blob/de09bec215675e9b0b...