A micro-optimization you will never need

https://www.romainguy.dev/posts/2024/a-micro-optimization-you-will-never-need/

by yen223 • 2 years ago

3 1 2 years ago

bhaney• 2 years ago

This doesn't really have anything to do with the article, but I got nerd-sniped into further optimizing the code it gave, and shaved off another 3 instructions with a little bit twiddling.

  fun bitsForSize(value: Int): Int {
    val x = 32 - value.countLeadingZeroBits()
    if (x < 13) return 13
    if (x > 18) return 0
    return x + ((x xor (x ushr 2)) and 1)
  }

I'd like to get it branchless, but can't think of a better way to do the weird clamping.

Godbolt playground I'm using: https://godbolt.org/z/7nr4Gb5G3

A micro-optimization you will never need

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