There are some Jira issues on this, but there doesn't seem to be a consensus on the way forward. Does someone have more information, is the general idea to wait for specialization to stabilise, or is there a plan, or even an intention, to stop relying on it?
As for stablizing packed_simd, It's completely unclear to me when that will land in stable rust. I recently had a project where I just ended up calling out to C code to handle vectorization.
EDIT: According to, https://github.com/rust-lang/lang-team/issues/29, the effort looks abandonded/deprioritized, so it may be a long time before it sees stable rust
packed_simd provides a convenient platform independent API to some subset of common SIMD operations. Rust's standard library does have pretty much everything up through AVX2 on x86 stabilized though: https://doc.rust-lang.org/core/arch/index.html --- So if you need vectorization on x86, Rust should hopefully have you covered.
If you need other platforms or AVX-512 though, then yeah, using either unstable Rust, C or Assembly is required.