perf: improve, specialize leading_zeros #485
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CodSpeed Performance ReportMerging #485 will not alter performanceComparing Summary
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prestwich
reviewed
Jun 13, 2025
| @@ -155,13 +155,24 @@ impl<const BITS: usize, const LIMBS: usize> Uint<BITS, LIMBS> { | |||
| #[inline] | |||
| #[must_use] | |||
| pub const fn leading_zeros(&self) -> usize { | |||
| let fixed = Self::MASK.leading_zeros() as usize; | |||
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this could be a computed const?
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doesn't matter, it's always optimized
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it doesn't matter for perf in this context, it does matter for potential reuse by other fns or downstream users. the question is whether it's more intuitive and legible to access this as Self::MASK.leading_zeros() or as Self::MASK_LEADING_ZEROS. I'm not convinced it's better either way (especailly as MASK is not exactly a clear constant name on its own)
prestwich
approved these changes
Jun 27, 2025
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specialize for <= u256
I couldn't figure out a way to have a branchless clz directly, so I opted to specialize for small bit widths instead by using u64/u128 primitives