Comment by immibis

You can have an ISA sufficiently generic to run on any CPU, or one sufficiently specific to efficiently exploit SIMD on a particular CPU. Never both. That's why some platforms provider higher-level operations, like element-wise multiplication of packed arrays. I can't see whether the actual WASM2 SIMD instructions are sufficiently generic because apparently I'm rate-limited on GitHub (???) and therefore can't see the spec.