Add NonZeroUn::is_power_of_two #81107
Merged
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This saves instructions on both new and old machines.
|
r? @kennytm (rust-highfive has picked a reviewer for you, use r? to override) |
rust-highfive
added
the
S-waiting-on-review
3 tasks
|
it's a simple unstable addition, so @bors r+ cc @rust-lang/libs |
|
📌 Commit 3e16e92 has been approved by |
bors
added
S-waiting-on-bors
|
@bors rollup |
m-ou-se
added a commit
to m-ou-se/rust
that referenced
this pull request
Jan 17, 2021
…=kennytm Add NonZeroUn::is_power_of_two This saves instructions on both new and old machines <https://rust.godbolt.org/z/4fjTMz> - On the default x64 target (with no fancy instructions available) it saves a few instructions by not needing to also check for zero. - On newer targets (with BMI1) it uses `BLSR` for super-short assembly. This can be used for things like checks against alignments stored in `NonZeroUsize`.
bors
added a commit
to rust-lang-ci/rust
that referenced
this pull request
Jan 17, 2021
Rollup of 13 pull requests Successful merges: - rust-lang#79298 (correctly deal with late-bound lifetimes in anon consts) - rust-lang#80031 (resolve: Reject ambiguity built-in attr vs different built-in attr) - rust-lang#80201 (Add benchmark and fast path for BufReader::read_exact) - rust-lang#80635 (Improve diagnostics when closure doesn't meet trait bound) - rust-lang#80765 (resolve: Simplify collection of traits in scope) - rust-lang#80932 (Allow downloading LLVM on Windows and MacOS) - rust-lang#80983 (Remove is_dllimport_foreign_item definition from cg_ssa) - rust-lang#81064 (Support non-stage0 check) - rust-lang#81080 (Force vec![] to expression position only) - rust-lang#81082 (BTreeMap: clean up a few more comments) - rust-lang#81084 (Use Option::map instead of open-coding it) - rust-lang#81095 (Use Option::unwrap_or instead of open-coding it) - rust-lang#81107 (Add NonZeroUn::is_power_of_two) Failed merges: r? `@ghost` `@rustbot` modify labels: rollup
# for free
to join this conversation on GitHub.
Already have an account?
# to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This saves instructions on both new and old machines https://rust.godbolt.org/z/4fjTMz
BLSRfor super-short assembly.This can be used for things like checks against alignments stored in
NonZeroUsize.EDIT: New demonstration now that this is available on nightly: https://rust.godbolt.org/z/7bPWxx