<random>: Optimize range adjustment in uniform_int
#4234
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Neither Clang nor MSVC is smart enough to optimize the previous code into the simple non-branching non-conditional move variant. (GCC actually is, but GCC does not matter in this context) See https://godbolt.org/z/T9GT7s5rG https://godbolt.org/z/eE7q9G9W8
CaseyCarter
approved these changes
Dec 5, 2023
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We usually ask for benchmarks to support performance improvement PRs, but I think codegen inspection suffices here. Thanks! |
StephanTLavavej
approved these changes
Dec 5, 2023
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I'm mirroring this to the MSVC-internal repo - please notify me if any further changes are pushed. |
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Thanks for improving the performance of everyone's favorite distribution, and congratulations on your first microsoft/STL commit! 😻 🚀 🎉 This will ship in VS 2022 17.10 Preview 1. |
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Neither Clang nor MSVC is smart enough to optimize the previous code into the simple non-branching non-conditional move variant. (GCC actually is, but GCC does not matter in this context)
See
https://godbolt.org/z/T9GT7s5rG
https://godbolt.org/z/eE7q9G9W8
Comment on the PR instructions:
I am working on custom distributions for Catch2, and implemented the range adjustment like this. Afterwards I went to check how the STLs do it and quick test showed that MSVC is better served with my implementation. Since this started as my original work, even though for different repo, I think that's fine.