Yeah. I'm going to be helping to work on expanding CI for OpenBLAS and have been diving into this stuff lately. See the discussion in this closed OpenBLAS issue gh-1968 [0] for instance. OpenBLAS’s Skylake kernels do rely heavily on intrinsics [1] for compilers that support them, but there's a wide range of architectures to support, and when hand-tuned assembly kernels work better, that's what are used. For example, [2].

[0] https://github.com/xianyi/OpenBLAS/issues/1968

[1] https://github.com/xianyi/OpenBLAS/blob/develop/kernel/x86_6...

[2] https://github.com/xianyi/OpenBLAS/blob/23693f09a26ffd8b60eb...