Optimize 128-bit integer formatting#68
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The compiler is unaware of the restricted range of the input, so it is unable to optimize out the final division and modulus. By doing this manually, we get a nontrivial performance gain.
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All of this code is just copied from libcore. Please send this optimization there first, and then it can get synced here. I would prefer to diverge as little as possible.
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Ah, I didn't realize it was a verbatim copy, just that it was largely copied. I'll do that momentarily. |
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…g, r=dtolnay Optimize 128-bit integer formatting The compiler is unaware of the restricted range of the input, so it is unable to optimize out the final division and modulus. By doing this manually, we get a nontrivial performance gain. r? @dtolnay (copied from dtolnay/itoa#68)
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…g, r=dtolnay Optimize 128-bit integer formatting The compiler is unaware of the restricted range of the input, so it is unable to optimize out the final division and modulus. By doing this manually, we get a nontrivial performance gain. r? @dtolnay (copied from dtolnay/itoa#68)
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…g, r=dtolnay Optimize 128-bit integer formatting The compiler is unaware of the restricted range of the input, so it is unable to optimize out the final division and modulus. By doing this manually, we get a nontrivial performance gain. r? @dtolnay (copied from dtolnay/itoa#68)
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…g, r=dtolnay Optimize 128-bit integer formatting The compiler is unaware of the restricted range of the input, so it is unable to optimize out the final division and modulus. By doing this manually, we get a nontrivial performance gain. r? @dtolnay (copied from dtolnay/itoa#68)
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…g, r=dtolnay Optimize 128-bit integer formatting The compiler is unaware of the restricted range of the input, so it is unable to optimize out the final division and modulus. By doing this manually, we get a nontrivial performance gain. r? @dtolnay (copied from dtolnay/itoa#68)
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The compiler is unaware of the restricted range of the input, so it is unable to optimize out the final division and modulus. By doing this manually, we get a nontrivial performance gain.
By running the included benchmark (
u128[max]/itoa) repeatedly, I see an improvement from 32.274 ns to 30.470 ns — a 5.6% gain.