To answer both my own questions. Rust does not seem to have this same problem:
https://godbolt.org/z/JpwcRN
But iterating over the loop with .iter_mut is different than iterating over 0..v.len(), which is interesting.
But iterating over the loop with .iter_mut is different than iterating over 0..v.len(), which is interesting.
Also you can use `-C target_cpu=native` and get AVX512 instructions on godbolt's.