riscv64: Implement SIMD popcnt#6587
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I'm happy to review if not but please feel free! |
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👋 Hey,
This PR Implements the SIMD
popcntinstruction for RISC-V. We don't have a native version of this, so we need to use one of the popular algorithms that normally replaces the native instruction. This is the variant that LLVM uses for element types larger thani8, they also have a shorter implementation fori8x16, but I didn't implement it here.I also checked what V8 produces and they do a loop that sums each bit. In our case that would involve having a custom instruction and I didn't really want to do that.