2019-10-31
Announcments
Rust 1.39 ships on Thursday!
Backport nominations
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“save-analysis: Account for async desugaring in async fn return types” #65936
- Accepted for beta backport
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“resolve: Turn the “non-empty glob must import something” error into a lint” #65539
- Accepted for beta backport
Working group sync
wg-pgo
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PGO is available in the stable compiler. Docs are in the rustc-dev-guide and the rustc-book
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Unfortunately we don’t observe significant performance gains from applying it (except for tiny synthetic test cases).
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@michaelwoerister asked for people to try PGO on irlo but haven’t gotten a lot of feedback.
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There is one interesting theory that Rust doesn’t profit as much as C++ because it defaults to having fewer compilation units and thus can make better inlining decisions in the non-PGO case.
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The working group will probably wind down as @michaelwoerister don’t have time to pursue further and there are no actual known issues in the implementation.
wg-pipelining
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Pipelining support has shipped in Rust 1.38.
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The working group is winding down.