And for even divisors you can separate the divisor into a power of two, and an o... | Hacker News

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im3w1l on Feb 21, 2017 | parent | context | favorite | on: How do compilers optimize divisions?

And for even divisors you can separate the divisor into a power of two, and an odd part. The odd part is checked as before, and the power of two is checked with an and mask.

raphlinus on Feb 21, 2017 [–]

An even trickier way to do this is to rotate right by the power of two factor between doing the multiply and the compare.

im3w1l on Feb 23, 2017 | [–]

That wouldn't work, because a number that is bigger than the threshold could become smaller than it after the rotation.

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