[stephencanon]

AVX512 doesn't itself imply Icelake+; the actual feature is FSRM (fast short rep movs), which is distinct from AVX512. In particular, Skylake Xeon and Cannon Lake, Cascade Lake, and Cooper Lake all have AVX512 but not FSRM, but my expectation is that all future architectures will have support, so I would expect memcpy and memset implementations tuned for Icelake and onwards to take advantage of it.