Refactor PRegSet. #178
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Refactor PRegSet. #178
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cfallin
approved these changes
Jun 5, 2024
src/lib.rs
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| /// Splits the given register index into parts to access the internal bit array. | ||
| const fn split_index(reg: PReg) -> (usize, usize) { | ||
| let index = reg.index(); | ||
| (index / Self::BITS, index % Self::BITS) |
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It should be optimized via strength reduction but just to be sure in unoptimized builds: could we use shifts and masking here instead? AFAIK, BITS will always be a power of two.
src/lib.rs
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| let bits = self.bits.get_mut(self.cur)?; | ||
| if *bits != 0 { | ||
| let bit = bits.trailing_zeros(); | ||
| *bits ^= 1 << bit; |
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Can we stick with the &= !(1 << bit) form we had before, here? Equivalent in this case and not a huge deal either way, just a preference, but this form for me is slightly more clear in intent (clearing a bit, vs. XOR which I ordinarily see for flipping the bit).
The changes will make it easier to increase the number of physical registers and register classes in the future.
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The changes will make it easier to increase the number of physical registers and register classes in the future.