Fix expansion performance regression #34652
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…(instead of by reference)" This reverts commit 5bf7970.
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cc @Manishearth |
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@bors: r+ |
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📌 Commit 547a930 has been approved by |
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⌛ Testing commit 547a930 with merge 70e1a95... |
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Fix expansion performance regression **syntax-[breaking-change] cc #31645** This fixes #34630 by reverting commit 5bf7970 of PR #33943, which landed in #34424. By removing the `Rc<_>` wrapping around `Delimited` and `SequenceRepetition` in `TokenTree`, 5bf7970 made cloning `TokenTree`s more expensive. While this had no measurable performance impact on the compiler's crates, it caused an order of magnitude performance regression on some macro-heavy code in the wild. I believe this is due to clones of `TokenTree`s in `macro_parser.rs` and/or `macro_rules.rs`. r? @nrc
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💔 Test failed - auto-win-msvc-64-opt |
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@bors: retry On Wed, Jul 6, 2016 at 11:13 AM, bors notifications@github.com wrote:
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⌛ Testing commit 547a930 with merge de78655... |
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Fix expansion performance regression **syntax-[breaking-change] cc #31645** This fixes #34630 by reverting commit 5bf7970 of PR #33943, which landed in #34424. By removing the `Rc<_>` wrapping around `Delimited` and `SequenceRepetition` in `TokenTree`, 5bf7970 made cloning `TokenTree`s more expensive. While this had no measurable performance impact on the compiler's crates, it caused an order of magnitude performance regression on some macro-heavy code in the wild. I believe this is due to clones of `TokenTree`s in `macro_parser.rs` and/or `macro_rules.rs`. r? @nrc
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syntax-[breaking-change] cc #31645
This fixes #34630 by reverting commit 5bf7970 of PR #33943, which landed in #34424.
By removing the
Rc<_>wrapping aroundDelimitedandSequenceRepetitioninTokenTree, 5bf7970 made cloningTokenTrees more expensive. While this had no measurable performance impact on the compiler's crates, it caused an order of magnitude performance regression on some macro-heavy code in the wild. I believe this is due to clones ofTokenTrees inmacro_parser.rsand/ormacro_rules.rs.r? @nrc