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Posted to github@arrow.apache.org by GitBox <gi...@apache.org> on 2021/07/31 04:55:24 UTC

[GitHub] [arrow] cyb70289 commented on pull request #10846: ARROW 13473: [C++] Add super-scalar impl for BitUtil::SetBitTo

cyb70289 commented on pull request #10846:
URL: https://github.com/apache/arrow/pull/10846#issuecomment-890291119


   Do you have benchmark results showing this code is faster than original one?
   Compilers are pretty smart in optimizing these common code patterns. Without solid benchmark data, I would prefer simpler code.
   
   Disassembler shows the dumb `if else` actually generates almost same code as this bithack trick. Modern CPUs all have `conditional move` instructions to remove trivial branches.
   https://godbolt.org/z/fqzs7rGev


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