Thread

1. sharktheone · 1790545296 · focus · HN ↗

   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.

   1. dwattttt · 1790550725 · focus · HN ↗

      I guarantee you with my lack of skill, my attempt at using portable simd will exist while using manual intrinsics I doubt I'd get there.

      The question for me is whether portable simd will result in faster code than plain auto-vectorisation; for the simplest loops auto has me beat (the few times I've tried it), but I imagine as the complexity grows I'll be more likely to try do something that breaks auto-vectorisation, and it'll be more obvious to me when I do that in portable simd.

      1. nextaccountic · 1790617919 · focus · HN ↗

         nowadays it doesn't matter if you personally don't have this particular expertise, people still expect you to use an agent to write this code
   2. astrange · 1790614986 · focus · HN ↗

      Portable SIMD is a bad abstraction. The only two good choices are "something like ISPC" (basically "autoscalarization", similar to GPU kernels) and "writing in assembly" (ffmpeg does this for a reason).

      1. Archit3ch · 1790620382 · focus · HN ↗

         Note that ISPC does not handle symbolic math e.g. sparsity preserving linear solvers or equation simplification a la Mathematica. Manual ASM does. ;)

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