8abf920985
Refactor `binary_search_by` to use conditional moves Refactor the if/else checking on `cmp::Ordering` variants to a "branchless" reassignment of left and right. This change results in fewer branches and instructions. https://rust.godbolt.org/z/698eYffTx --- I saw consistent benchmark improvements locally. Performance of worst case seems about the same, maybe slightly faster for the L3 test. Current ``` slice::binary_search_l1 43.00ns/iter +/- 3.00ns slice::binary_search_l1_with_dups 25.00ns/iter +/- 0.00ns slice::binary_search_l1_worst_case 10.00ns/iter +/- 0.00ns slice::binary_search_l2 64.00ns/iter +/- 1.00ns slice::binary_search_l2_with_dups 42.00ns/iter +/- 0.00ns slice::binary_search_l2_worst_case 16.00ns/iter +/- 0.00ns slice::binary_search_l3 132.00ns/iter +/- 2.00ns slice::binary_search_l3_with_dups 108.00ns/iter +/- 2.00ns slice::binary_search_l3_worst_case 33.00ns/iter +/- 3.00ns ``` This PR ``` slice::binary_search_l1 21.00ns/iter +/- 0.00ns slice::binary_search_l1_with_dups 14.00ns/iter +/- 0.00ns slice::binary_search_l1_worst_case 9.00ns/iter +/- 0.00ns slice::binary_search_l2 34.00ns/iter +/- 0.00ns slice::binary_search_l2_with_dups 23.00ns/iter +/- 0.00ns slice::binary_search_l2_worst_case 16.00ns/iter +/- 0.00ns slice::binary_search_l3 92.00ns/iter +/- 3.00ns slice::binary_search_l3_with_dups 63.00ns/iter +/- 1.00ns slice::binary_search_l3_worst_case 29.00ns/iter +/- 0.00ns ``` |
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|---|---|---|
| .. | ||
| iter | ||
| ascii.rs | ||
| cmp.rs | ||
| index.rs | ||
| iter.rs | ||
| memchr.rs | ||
| mod.rs | ||
| raw.rs | ||
| rotate.rs | ||
| select.rs | ||
| sort.rs | ||
| specialize.rs | ||