Fix poor worst case performance of set intersection #57043
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…hat) on asymmetrically sized sets and extend unit tests slightly beyond that
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cc @rust-lang/libs |
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r? @bluss |
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📌 Commit cef2e2f has been approved by |
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Fix poor worst case performance of set intersection Specifically, intersection of asymmetrically sized sets when the large set is on the left. See also the [latest answer on stackoverflow](https://stackoverflow.com/questions/35439376/python-set-intersection-is-faster-then-rust-hashset-intersection). Also applied to the union member, where the effect is much less but still measurable. Formatted the changed code only, does not increase the error count reported by tidy check, and tried to adhere to the spirit of the unit tests.
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Fix poor worst case performance of set intersection Specifically, intersection of asymmetrically sized sets when the large set is on the left. See also the [latest answer on stackoverflow](https://stackoverflow.com/questions/35439376/python-set-intersection-is-faster-then-rust-hashset-intersection). Also applied to the union member, where the effect is much less but still measurable. Formatted the changed code only, does not increase the error count reported by tidy check, and tried to adhere to the spirit of the unit tests.
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Rollup of 8 pull requests Successful merges: - #57043 (Fix poor worst case performance of set intersection) - #57480 (Clean up and fix a bug in query plumbing) - #57481 (provide suggestion for invalid boolean cast) - #57540 (Modify some parser diagnostics to continue evaluating beyond the parser) - #57570 (Querify local `plugin_registrar_fn` and `proc_macro_decls_static`) - #57572 (Unaccept `extern_in_paths`) - #57585 (Recover from item trailing semicolon) - #57589 (Add a debug_assert to Vec::set_len) Failed merges: r? @ghost
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improve worst-case performance of HashSet.is_subset One more simple optimization opportunity for HashSet that was applied in BTreeSet in rust-lang#59186 (and wasn't in rust-lang#57043). Already covered by the existing unit test. r? @KodrAus
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Union was actually deoptimization, see #66280 |
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Specifically, intersection of asymmetrically sized sets when the large set is on the left. See also the latest answer on stackoverflow.
Also applied to the union member, where the effect is much less but still measurable.
Formatted the changed code only, does not increase the error count reported by tidy check, and tried to adhere to the spirit of the unit tests.