In 2018, People are still using glibc 2.17, which was released in February 2013, on SKX, even when the current released glibc 2.28 has the new memory, string and math functions optimized for SKX. The same thing will happen five years from now.
The CPU runtime C library for x86-64, libcpu-rt-c:
The latest memory, string functions from glibc Binary compatible with any x86-64 OSes. Link directly or LD_PRELOAD.