Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Only call the closure parameter of Iterator::is_sorted_by_key once per item #62473

Merged
merged 1 commit into from Jul 8, 2019

Conversation

Projects
None yet
7 participants
@timvermeulen
Copy link
Contributor

commented Jul 7, 2019

See #53485 (comment).

This changes Iterator::is_sorted_by_key to only call the given closure once for each item, which allows us to pass the items to the closure by value instead of by reference.

Important: is_sorted_by_key for slices and slice iterators is now no longer implemented in terms of the custom slice::Iter::is_sorted_by implementation. It's a trade-off: we could forward slice::Iter::is_sorted_by_key to it directly for potential SIMD benefits, but that would mean that the closure is potentially called twice for (almost) every element of the slice.

@rust-highfive

This comment has been minimized.

Copy link
Collaborator

commented Jul 7, 2019

r? @aidanhs

(rust_highfive has picked a reviewer for you, use r? to override)

@Centril

This comment has been minimized.

Copy link
Member

commented Jul 7, 2019

@rust-highfive rust-highfive assigned scottmcm and unassigned aidanhs Jul 7, 2019

@scottmcm

This comment has been minimized.

Copy link
Member

commented Jul 8, 2019

Well, this seems reasonable to me and the signature change is unstable so if libs is unhappy with it we can always revert it 🙃, so

@bors r+

@bors

This comment has been minimized.

Copy link
Contributor

commented Jul 8, 2019

📌 Commit 98b54fb has been approved by scottmcm

@bors

This comment has been minimized.

Copy link
Contributor

commented Jul 8, 2019

⌛️ Testing commit 98b54fb with merge 78ca1bd...

bors added a commit that referenced this pull request Jul 8, 2019

Auto merge of #62473 - timvermeulen:is_sorted_by_key, r=scottmcm
Only call the closure parameter of Iterator::is_sorted_by_key once per item

See #53485 (comment).

This changes `Iterator::is_sorted_by_key` to only call the given closure once for each item, which allows us to pass the items to the closure by value instead of by reference.

**Important**: `is_sorted_by_key` for slices and slice iterators is now no longer implemented in terms of the custom `slice::Iter::is_sorted_by` implementation. It's a trade-off: we could forward `slice::Iter::is_sorted_by_key` to it directly for potential SIMD benefits, but that would mean that the closure is potentially called twice for (almost) every element of the slice.
@bors

This comment has been minimized.

Copy link
Contributor

commented Jul 8, 2019

☀️ Test successful - checks-azure, checks-travis, status-appveyor
Approved by: scottmcm
Pushing 78ca1bd to master...

@bors bors added the merged-by-bors label Jul 8, 2019

@bors bors merged commit 98b54fb into rust-lang:master Jul 8, 2019

4 checks passed

homu Test successful
Details
pr Build #20190707.55 succeeded
Details
pr (Linux mingw-check) Linux mingw-check succeeded
Details
pr (Linux x86_64-gnu-llvm-6.0) Linux x86_64-gnu-llvm-6.0 succeeded
Details

@timvermeulen timvermeulen deleted the timvermeulen:is_sorted_by_key branch Jul 8, 2019

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
You can’t perform that action at this time.