Add NonZeroUn::is_power_of_two #81107
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This saves instructions on both new and old machines.
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r? @kennytm (rust-highfive has picked a reviewer for you, use r? to override) |
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it's a simple unstable addition, so @bors r+ cc @rust-lang/libs |
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📌 Commit 3e16e92 has been approved by |
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@bors rollup |
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…=kennytm Add NonZeroUn::is_power_of_two This saves instructions on both new and old machines <https://rust.godbolt.org/z/4fjTMz> - On the default x64 target (with no fancy instructions available) it saves a few instructions by not needing to also check for zero. - On newer targets (with BMI1) it uses `BLSR` for super-short assembly. This can be used for things like checks against alignments stored in `NonZeroUsize`.
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Rollup of 13 pull requests Successful merges: - rust-lang#79298 (correctly deal with late-bound lifetimes in anon consts) - rust-lang#80031 (resolve: Reject ambiguity built-in attr vs different built-in attr) - rust-lang#80201 (Add benchmark and fast path for BufReader::read_exact) - rust-lang#80635 (Improve diagnostics when closure doesn't meet trait bound) - rust-lang#80765 (resolve: Simplify collection of traits in scope) - rust-lang#80932 (Allow downloading LLVM on Windows and MacOS) - rust-lang#80983 (Remove is_dllimport_foreign_item definition from cg_ssa) - rust-lang#81064 (Support non-stage0 check) - rust-lang#81080 (Force vec![] to expression position only) - rust-lang#81082 (BTreeMap: clean up a few more comments) - rust-lang#81084 (Use Option::map instead of open-coding it) - rust-lang#81095 (Use Option::unwrap_or instead of open-coding it) - rust-lang#81107 (Add NonZeroUn::is_power_of_two) Failed merges: r? `@ghost` `@rustbot` modify labels: rollup
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This saves instructions on both new and old machines https://rust.godbolt.org/z/4fjTMz
BLSRfor super-short assembly.This can be used for things like checks against alignments stored in
NonZeroUsize.EDIT: New demonstration now that this is available on nightly: https://rust.godbolt.org/z/7bPWxx