Why can't it just run dynamic feature detection to see if it needs to load e.g. a SISD shim version of the function which is exactly the same except the intrinsic is replaced with a generic implementation?
Or at least the other way around: if a function is declared with dynamic feature detection and a default path exists why can't it be declared safe by the compiler?
The thing is that is not yet in-build in the lang. Let the crates sort some problems before commit it in the lang is like part of the philosophy of rust.
For example, rust change the hash implementation after certain crate prove it worthy.
Or at least the other way around: if a function is declared with dynamic feature detection and a default path exists why can't it be declared safe by the compiler?