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A comment on Bitwise Division. Parent comment

Re:Bitwise Division by eru on Wednesday March 01, 2023 @07:03AM (#34981402)
See https://godbolt.org/z/3Yqbceaza for what godbolt says clang produces.

Keep in mind that this doesn't use the fact that we know that the input is between 0 to 63.

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Re:Bitwise Division by workaccount1 on Wednesday March 01, 2023 @07:49AM (#34981785)
> Keep in mind that this doesn't use the fact that we know that the input is between 0 to 63.

You can use __builtin_assume for this: https://godbolt.org/z/K4jKhxnTq

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Re:Bitwise Division by pantalaimon on Wednesday March 01, 2023 @08:38AM (#34982233)
An assert() also does the trick: https://godbolt.org/z/MecvMGPdW
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Re:Bitwise Division by RenThraysk on Wednesday March 01, 2023 @03:46PM (#34988083)
9*x/64 still reduces to 2 instructions

https://godbolt.org/z/6WsWqh4ah

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