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Merged
merged 1 commit into from
Aug 9, 2025
Merged

Optimize char::is_alphanumeric #145027

merged 1 commit into from
Aug 9, 2025
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Kmeakin
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@Kmeakin Kmeakin commented Aug 6, 2025

Avoid an unnecessary call to unicode::Alphabetic when self is an ASCII digit (ie 0..=9).

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Optimize char::is_alphanumeric
bf50209 
Avoid an unnecessary call to `unicode::Alphabetic` when `self` is an
ASCII digit (ie `0..=9`).
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@rustbot rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-libs Relevant to the library team, which will review and decide on the PR/issue. labels Aug 6, 2025
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So this does seem plausible, but also it makes things slower for things that aren't actually ASCII because there's another check.

Do you have some benchmark results showing that it's at least still better on mixed text? I think there's some data in the core benches that can be used to show that on a chinese wikipedia page or similar.

Relatedly, if this is worth doing it feels like it's probably worth doing everywhere, and in the process updating the data generator to not include the ascii cases, requiring instead that the needle passed to skip_search isn't ascii.

library/core/src/char/methods.rs
Comment on lines +923 to +924
if self.is_ascii() {
self.is_ascii_alphanumeric()
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unsure: with https://github.com/rust-lang/rust/pull/143467/files#diff-5f02a23b56d56296cfa0b9f2dc32075d26638c5aa232c4aa551131785dad8887R759 about to land, should this instead go via that?

Suggested change
if self.is_ascii() {
self.is_ascii_alphanumeric()
if let Some(a) = self.as_ascii() {
a.is_alphanumeric()

(Don't know how much it matters, but I always prefer using types to avoid boolean blindness, where possible.)

@scottmcm scottmcm added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Aug 7, 2025
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Kmeakin commented Aug 9, 2025

Relatedly, if this is worth doing it feels like it's probably worth doing everywhere, and in the process updating the data generator to not include the ascii cases, requiring instead that the needle passed to skip_search isn't ascii.

I actually already have a WIP branch that does just that as well as some other tricks to reduce the size of the unicode tables. I will submit it when it is ready

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scottmcm commented Aug 9, 2025

You know what, looking again is_uppercase and is_whitespace and such essentially have this, so might as well just do it.

@bors r+

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bors commented Aug 9, 2025

📌 Commit bf50209 has been approved by scottmcm

It is now in the queue for this repository.

@bors bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Aug 9, 2025
@Zalathar Zalathar mentioned this pull request Aug 9, 2025
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bors added a commit that referenced this pull request Aug 9, 2025
@bors
Auto merge of #145142 - Zalathar:rollup-oi6s8kg, r=Zalathar
f2aa3e0 
Rollup of 23 pull requests

Successful merges:

 - #141658 (rustdoc search: prefer stable items in search results)
 - #141828 (Add diagnostic explaining STATUS_STACK_BUFFER_OVERRUN not only being used for stack buffer overruns if link.exe exits with that exit code)
 - #144823 (coverage: Extract HIR-related helper code out of the main module)
 - #144883 (Remove unneeded `drop_in_place` calls)
 - #144923 (Move several more float tests to floats/mod.rs)
 - #144988 (Add annotations to the graphviz region graph on region origins)
 - #145010 (Couple of minor abi handling cleanups)
 - #145017 (Explicitly disable vector feature on s390x baseline of bad-reg test)
 - #145027 (Optimize `char::is_alphanumeric`)
 - #145050 (add member constraints tests)
 - #145073 (update enzyme submodule to handle llvm 21)
 - #145080 (Escape diff strings in MIR dataflow graphviz)
 - #145082 (Fix some bad formatting in `-Zmacro-stats` output.)
 - #145083 (Fix cross-compilation of Cargo)
 - #145096 (Fix wasm target build with atomics feature)
 - #145097 (remove unnecessary `TypeFoldable` impls)
 - #145100 (Rank doc aliases lower than equivalently matched items)
 - #145103 (rustc_metadata: remove unused private trait impls)
 - #145115 (defer opaque type errors, generally greatly reduce tainting)
 - #145119 (rustc_public: fix missing parenthesis in pretty discriminant)
 - #145124 (Recover `for PAT = EXPR {}`)
 - #145132 (Refactor map_unit_fn lint)
 - #145134 (Reduce indirect assoc parent queries)

r? `@ghost`
`@rustbot` modify labels: rollup
bors added a commit that referenced this pull request Aug 9, 2025
@bors
Auto merge of #145142 - Zalathar:rollup-oi6s8kg, r=Zalathar
ca77504 
Rollup of 23 pull requests

Successful merges:

 - #141658 (rustdoc search: prefer stable items in search results)
 - #141828 (Add diagnostic explaining STATUS_STACK_BUFFER_OVERRUN not only being used for stack buffer overruns if link.exe exits with that exit code)
 - #144823 (coverage: Extract HIR-related helper code out of the main module)
 - #144883 (Remove unneeded `drop_in_place` calls)
 - #144923 (Move several more float tests to floats/mod.rs)
 - #144988 (Add annotations to the graphviz region graph on region origins)
 - #145010 (Couple of minor abi handling cleanups)
 - #145017 (Explicitly disable vector feature on s390x baseline of bad-reg test)
 - #145027 (Optimize `char::is_alphanumeric`)
 - #145050 (add member constraints tests)
 - #145073 (update enzyme submodule to handle llvm 21)
 - #145080 (Escape diff strings in MIR dataflow graphviz)
 - #145082 (Fix some bad formatting in `-Zmacro-stats` output.)
 - #145083 (Fix cross-compilation of Cargo)
 - #145096 (Fix wasm target build with atomics feature)
 - #145097 (remove unnecessary `TypeFoldable` impls)
 - #145100 (Rank doc aliases lower than equivalently matched items)
 - #145103 (rustc_metadata: remove unused private trait impls)
 - #145115 (defer opaque type errors, generally greatly reduce tainting)
 - #145119 (rustc_public: fix missing parenthesis in pretty discriminant)
 - #145124 (Recover `for PAT = EXPR {}`)
 - #145132 (Refactor map_unit_fn lint)
 - #145134 (Reduce indirect assoc parent queries)

r? `@ghost`
`@rustbot` modify labels: rollup
@bors bors merged commit 2a7354e into rust-lang:master Aug 9, 2025
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@rustbot rustbot added this to the 1.91.0 milestone Aug 9, 2025
rust-timer added a commit that referenced this pull request Aug 9, 2025
@rust-timer
Unrolled build for #145027
f5b8097 
Rollup merge of #145027 - Kmeakin:km/optimize-char-is-alphanumeric, r=scottmcm

Optimize `char::is_alphanumeric`

Avoid an unnecessary call to `unicode::Alphabetic` when `self` is an ASCII digit (ie `0..=9`).
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jieyouxu commented Aug 9, 2025

Hi bors this already merged
@bors r-

@bors bors added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Aug 9, 2025
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jieyouxu commented Aug 9, 2025

@rustbot label: -S-waiting-on-author +S-waiting-on-bors +merged-by-bors

@rustbot rustbot added merged-by-bors This PR was explicitly merged by bors. S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Aug 9, 2025
@Kmeakin Kmeakin mentioned this pull request Aug 10, 2025
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