alt Hacker NewsIsn't the faster approach SIMD [edit: or GPU]? A 1.05x to 1.90x speedup is great. A 16x speedup is better!
They could be orthogonal improvements, but if I were prioritizing, I'd go for SIMD first.
I searched for asin on Intel's intrinsics guide. They have a AVX-512 instrinsic `_mm512_asin_ps` but it says "sequence" rather than single-instruction. Presumably the actual sequence they use is in some header file somewhere, but I don't know off-hand where to look, so I don't know how it compares to a SIMDified version of `fast_asin_cg`.
https://www.intel.com/content/www/us/en/docs/intrinsics-guid...
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I don't do much float work but I don't think there is a single regular sine instruction only old x87 float stack ones.
I was curious what "sequence" would end up being but my compiler is too old for that intrinsic. Even godbolt didn't help for gcc or clang but it did reveal that icc produced a call https://godbolt.org/z/a3EsKK4aY
I don’t know much about raytracing but it’s probably tricky to orchestrate all those asin calls so that the input and output memory is aligned and contiguous. My uneducated intuition is that there’s little regularity as to which pixels will take which branches and will end up requiring which asin calls, but I might be wrong.