Rust's SIMD ecosystem finally grows up
The state of SIMD in Rust in 2026
Sergey "Shnatsel" Davidoff surveys the state of SIMD in Rust for 2026, now as a maintainer of Fearless SIMD. He compares five approaches: std::simd, fearless_simd, wide, pulp, and macerator, across multiversioning, portability, and instruction set support. The takeaway: automatic vectorization remains unreliable, std::simd is nightly-only and incomplete, and fearless_simd emerges as the most complete all-in-one solution.
Floats are weird. Even something as trivial as summing an array of floats with reasonable precision gets surprisingly involved.
- sharktheone
I am hoping for portable SIMD so much. But I still think that often a manually rolled SIMD will be faster.
Also the state of SIMD in Cranelift is also very WIP. They pretty much just support a subset of 128bit vectors with some rare exceptions.
- the__alchemist
I am using my own lib, `lin_alg`, which apes core_simd for floating point values, and extends the concept to vectors and quaternions. I will eventually replace the floating point portions with core::simd upon its arrival in stable Rust.
Downside: It's currently x86 only.
- Archit3ch
Hot take: there is no portable SIMD.
You can either have performance (=write manual ASM for each platform), or portability, but not both.
What so-called "portable SIMD" libraries give you is "portable auto-vectorization". "Portable performance" is a global property of the algorithm. Relying on auto-vectorization will result in e.g. sub-optimal register spills in practice. The microbenchmarks will look great, though. ;)