Hi @zchee thanks for the PR! It does seem that we never originally put a Makefile build dependency between the cpu/cpu.go file and the generated *.s files. When a new X86Feature bit flag is introduced—AVX512FP16 in this case—it will change the values of the subsequent flags due to the use of iota. This is fine, but we need to regenerate the *.s files as they use the same bit flags during build time.