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| author | Dylan DPC <99973273+Dylan-DPC@users.noreply.github.com> | 2022-04-09 18:26:30 +0200 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2022-04-09 18:26:30 +0200 |
| commit | 7726265ae0d3d2b37b4254980a72d5d5347fb92d (patch) | |
| tree | b7068e427d11a5cbc64f5da386e58e102f671235 /library/std/src/sys/unix/process/process_unix.rs | |
| parent | 2464ea251010f6de62ec875b32f3463dfa326cfb (diff) | |
| parent | 1e6365d0751c0c7b88a30ad5eab0becb6cc87f7e (diff) | |
| download | rust-7726265ae0d3d2b37b4254980a72d5d5347fb92d.tar.gz rust-7726265ae0d3d2b37b4254980a72d5d5347fb92d.zip | |
Rollup merge of #95831 - redzic:xor-uppercase, r=workingjubilee
Use bitwise XOR in to_ascii_uppercase This saves an instruction compared to the previous approach, which was to unset the fifth bit with bitwise OR. Comparison of generated assembly on x86: https://godbolt.org/z/GdfvdGs39 This can also affect autovectorization, saving SIMD instructions as well: https://godbolt.org/z/cnPcz75T9 Not sure if `u8::to_ascii_lowercase` should also be changed, since using bitwise OR for that function does not require an extra bitwise negate since the code is setting a bit rather than unsetting a bit. `char::to_ascii_uppercase` already uses XOR, so no change seems to be required there.
Diffstat (limited to 'library/std/src/sys/unix/process/process_unix.rs')
0 files changed, 0 insertions, 0 deletions