Getting explicit SIMD on stable Rust

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For someone that has written code for a fair amount of year using SIMD in C/C++ I would prefer a two step approach:

  1. Implement the intrinsics as they are listed in the Intel Manuals (and same approach for other CPUs) in the case of Intel they already provide lots of documantation for them and people coming from the C/C++ world would be very familiar with them. As Clang already supports them with LLVM they should match quite good. If potential change to another backend it would still be possible to use them as there are docs around for them anyway.

  2. Approach 1 is fairly typeless this is actually a good thing when writing optimized SIMD code where you may do floating point tricks directly with integer instructions. As always with something close to assembly it’s easy to do something wrong. Step 2 would would be something more typed (I think I have seen things like f32x4, i16x8,etc) which is more user friendly but can make it somewhat non-intuitive when doing trickery (you would need to a fair amount of casting)

I can see Rust wanting to go more for approach 2 but I think it would be nice to have approach 1 also.

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