Yes, it works with AMD CPUs as well as various ARM ones, e.g. Apple silicon.

See for instance https://github.com/ispc/ispc/pull/2160

Yes, works well with AMD. You can compile multi-target so that you'll have e.g. SSE4.2, AVX2, AVX512 support built to your binaries and the best (widest) version is picked by the runtime automatically.