Optimize char::encode_utf8#145515
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Save a few instructions in `encode_utf8_raw_unchecked` by performing manual CSE.
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Do you have benchmarks or assembly examples showing that this is better? |
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Yes: https://godbolt.org/z/Ysfqn53oK |
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It looks like the old impl would use some vector instructions to assemble the 4-byte wide case on newer CPUs (e.g., see https://godbolt.org/z/G457TP9nW) but I'm not convinced that's a good thing and this seems reasonable enough. @bors r+ rollup=iffy |
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…f8, r=Mark-Simulacrum Optimize `char::encode_utf8` Save a few instructions in `encode_utf8_raw_unchecked` by performing manual CSE.
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Rollup of 7 pull requests Successful merges: - #144452 (std/sys/fd: Relax `READ_LIMIT` on Darwin) - #145307 (Fix `LazyLock` poison panic message) - #145515 (Optimize `char::encode_utf8`) - #145540 (interpret/allocation: get_range on ProvenanceMap) - #145774 (Remove default opts from config) - #145780 (Do not warn about missing change ID in tarball builds) - #145781 (Remove profile section from Clippy) r? `@ghost` `@rustbot` modify labels: rollup
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…f8, r=Mark-Simulacrum Optimize `char::encode_utf8` Save a few instructions in `encode_utf8_raw_unchecked` by performing manual CSE.
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…f8, r=Mark-Simulacrum Optimize `char::encode_utf8` Save a few instructions in `encode_utf8_raw_unchecked` by performing manual CSE.
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Rollup of 14 pull requests Successful merges: - #143898 (opt-dist: rebuild rustc when doing static LLVM builds) - #144452 (std/sys/fd: Relax `READ_LIMIT` on Darwin) - #145234 (match exhaustiveness diagnostics: show a trailing comma on singleton tuple consructors in witness patterns (and clean up a little)) - #145515 (Optimize `char::encode_utf8`) - #145540 (interpret/allocation: get_range on ProvenanceMap) - #145670 (port `sanitize` attribute to the new parsing infrastructure) - #145713 (next-solver: fix `feature(const_trait_impl)` bootstrap) - #145729 (Remove two duplicated crates) - #145744 (miri: also detect aliasing of in-place argument and return place) - #145774 (Remove default opts from config) - #145781 (Remove profile section from Clippy) - #145782 (rustdoc: make attributes render consistently) - #145787 (citool: cleanup `mismatched_lifetime_syntaxes` warnings) - #145791 (Fix ICE when validating transmuting ZST to inhabited enum) r? `@ghost` `@rustbot` modify labels: rollup
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Rollup merge of #145515 - Kmeakin:km/optimize-char-encode-utf8, r=Mark-Simulacrum Optimize `char::encode_utf8` Save a few instructions in `encode_utf8_raw_unchecked` by performing manual CSE.
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Rollup of 14 pull requests Successful merges: - rust-lang/rust#143898 (opt-dist: rebuild rustc when doing static LLVM builds) - rust-lang/rust#144452 (std/sys/fd: Relax `READ_LIMIT` on Darwin) - rust-lang/rust#145234 (match exhaustiveness diagnostics: show a trailing comma on singleton tuple consructors in witness patterns (and clean up a little)) - rust-lang/rust#145515 (Optimize `char::encode_utf8`) - rust-lang/rust#145540 (interpret/allocation: get_range on ProvenanceMap) - rust-lang/rust#145670 (port `sanitize` attribute to the new parsing infrastructure) - rust-lang/rust#145713 (next-solver: fix `feature(const_trait_impl)` bootstrap) - rust-lang/rust#145729 (Remove two duplicated crates) - rust-lang/rust#145744 (miri: also detect aliasing of in-place argument and return place) - rust-lang/rust#145774 (Remove default opts from config) - rust-lang/rust#145781 (Remove profile section from Clippy) - rust-lang/rust#145782 (rustdoc: make attributes render consistently) - rust-lang/rust#145787 (citool: cleanup `mismatched_lifetime_syntaxes` warnings) - rust-lang/rust#145791 (Fix ICE when validating transmuting ZST to inhabited enum) r? `@ghost` `@rustbot` modify labels: rollup
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…f8, r=Mark-Simulacrum Optimize `char::encode_utf8` Save a few instructions in `encode_utf8_raw_unchecked` by performing manual CSE.
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Save a few instructions in
encode_utf8_raw_uncheckedby performing manual CSE.