I don't think so. I've tried recreating Issue18740 for memclr, but it proved to be quite difficult, memory is either cleared in bulk before allocation or memclr is inlined into single MOVL. More generally speaking it makes sense to have different implementation of memmove and memclr (at least for larger sizes), due to different memory access pattern. E. g. memmove will trash 2x cache and will stop fitting into uop cache earlier, because it needs 2x uops (extra read per each write)

Thanks for looking into it, Ilya. Closing.