I'm using Rust (nightly) std::simd for my 3d math stuff. It doesn't come with matrix and quaternion functions but they were relatively simple to implement based on known good algorithms. But you do get basic arithmetic operators without having to implement std::ops by hand (or with macros).
What was/is not pretty is adding some generics so the same code can work with f32 and f64. I did manage to get something that works but it's so ugly that I didn't want to release it. I'm sure it could be improved but what I got works well enough and I haven't needed to touch it in a few years.
std::simd is quite pleasant to work with and most importantly it allows a zero cost fallback to CPU specific intrinsics when needed.
What was/is not pretty is adding some generics so the same code can work with f32 and f64. I did manage to get something that works but it's so ugly that I didn't want to release it. I'm sure it could be improved but what I got works well enough and I haven't needed to touch it in a few years.
std::simd is quite pleasant to work with and most importantly it allows a zero cost fallback to CPU specific intrinsics when needed.