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by jsheard
782 days ago
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It's not that bad, all x86 processors have the BSR instruction which can be mapped to LZCNT semantics with just a few extra instructions. Left to right - modern x86-64, baseline x86-64, baseline i686: https://rust.godbolt.org/z/nGsM35TEo Maybe you're thinking of POPCNT, which hurts a lot more if it doesn't compile down to the native instruction: https://rust.godbolt.org/z/xcxG3v4Mn |
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