Pull Derefer before ElaborateDrops #98145

ouz-a · 2022-06-15T19:04:53Z

Follow up work to #97025 #96549 #96116 #95887 #95649

This moves Derefer before ElaborateDrops and creates a new Rvalue called VirtualRef that allows us to bypass many constraints for DerefTemp.

r? @oli-obk

rust-highfive · 2022-06-15T19:04:56Z

Some changes occured to the CTFE / Miri engine

cc @rust-lang/miri

bors · 2022-06-20T06:17:21Z

☔ The latest upstream changes (presumably #97931) made this pull request unmergeable. Please resolve the merge conflicts.

compiler/rustc_borrowck/src/lib.rs

compiler/rustc_const_eval/src/interpret/step.rs

compiler/rustc_const_eval/src/transform/check_consts/qualifs.rs

compiler/rustc_middle/src/mir/mod.rs

compiler/rustc_middle/src/mir/tcx.rs

compiler/rustc_middle/src/mir/type_foldable.rs

compiler/rustc_mir_dataflow/src/move_paths/builder.rs

compiler/rustc_mir_transform/src/elaborate_drops.rs

compiler/rustc_middle/src/mir/mod.rs

oli-obk · 2022-06-21T10:15:05Z

@rustbot author

compiler/rustc_middle/src/mir/mod.rs

bors · 2022-06-21T13:46:31Z

☔ The latest upstream changes (presumably #95576) made this pull request unmergeable. Please resolve the merge conflicts.

bors · 2022-06-22T02:56:33Z

☔ The latest upstream changes (presumably #98359) made this pull request unmergeable. Please resolve the merge conflicts.

oli-obk · 2022-06-23T07:48:00Z

@bors r+

bors · 2022-06-23T07:48:01Z

📌 Commit aa91716 has been approved by oli-obk

bors · 2022-06-23T07:48:04Z

🌲 The tree is currently closed for pull requests below priority 1000. This pull request will be tested once the tree is reopened.

oli-obk · 2022-07-12T13:06:40Z

@bors r+ rollup=iffy

bors · 2022-07-12T13:06:41Z

📌 Commit b4c3a2a has been approved by oli-obk

It is now in the queue for this repository.

bors · 2022-07-13T14:32:36Z

⌛ Testing commit b4c3a2a with merge 42bd138...

bors · 2022-07-13T17:13:20Z

☀️ Test successful - checks-actions
Approved by: oli-obk
Pushing 42bd138 to master...

rust-timer · 2022-07-13T18:32:55Z

Finished benchmarking commit (42bd138): comparison url.

Instruction count

Primary benchmarks: 😿 relevant regressions found
Secondary benchmarks: 😿 relevant regressions found

	mean¹	max	count²
Regressions 😿 (primary)	0.5%	0.8%	13
Regressions 😿 (secondary)	0.7%	1.1%	20
Improvements 🎉 (primary)	N/A	N/A	0
Improvements 🎉 (secondary)	N/A	N/A	0
All 😿🎉 (primary)	0.5%	0.8%	13

Max RSS (memory usage)

Results

Primary benchmarks: no relevant changes found
Secondary benchmarks: mixed results

	mean¹	max	count²
Regressions 😿 (primary)	N/A	N/A	0
Regressions 😿 (secondary)	3.0%	3.1%	2
Improvements 🎉 (primary)	N/A	N/A	0
Improvements 🎉 (secondary)	-9.1%	-9.1%	1
All 😿🎉 (primary)	N/A	N/A	0

Cycles

Results

Primary benchmarks: 🎉 relevant improvement found
Secondary benchmarks: 🎉 relevant improvement found

	mean¹	max	count²
Regressions 😿 (primary)	N/A	N/A	0
Regressions 😿 (secondary)	N/A	N/A	0
Improvements 🎉 (primary)	-3.1%	-3.1%	1
Improvements 🎉 (secondary)	-2.9%	-2.9%	1
All 😿🎉 (primary)	-3.1%	-3.1%	1

If you disagree with this performance assessment, please file an issue in rust-lang/rustc-perf.

Next Steps: If you can justify the regressions found in this perf run, please indicate this with @rustbot label: +perf-regression-triaged along with sufficient written justification. If you cannot justify the regressions please open an issue or create a new PR that fixes the regressions, add a comment linking to the newly created issue or PR, and then add the perf-regression-triaged label to this PR.

@rustbot label: +perf-regression

the arithmetic mean of the percent change ↩ ↩² ↩³
number of relevant changes ↩ ↩² ↩³

oli-obk · 2022-07-14T10:53:53Z

hmm... looks like all mir queries got a few percent slower. I guess open an issue to track this regression to see if it goes away once we get rid of the new Rvalue

Pull Derefer before ElaborateDrops _Follow up work to rust-lang#97025 rust-lang#96549 rust-lang#96116 rust-lang#95887 #95649_ This moves `Derefer` before `ElaborateDrops` and creates a new `Rvalue` called `VirtualRef` that allows us to bypass many constraints for `DerefTemp`. r? `@oli-obk`

rylev · 2022-07-19T15:19:20Z

@oli-obk @ouz-a can you open an issue to track the regression here? I'm nervous that this will just get lost.

Dylan-DPC · 2022-07-19T15:22:04Z

@oli-obk @ouz-a can you open an issue to track the regression here? I'm nervous that this will just get lost.

@rylev i opened #99473 for this

ouz-a · 2022-07-19T15:22:05Z

@oli-obk @ouz-a can you open an issue to track the regression here? I'm nervous that this will just get lost.

I was planning to open a PR without the new Rvalue

Optimize `UnDerefer` Addresses the performance [issues](rust-lang#98145 (comment)) faced here. r? `@oli-obk`

Rewrite `UnDerefer` Currently, `UnDerefer` is used by drop elaboration to undo the effects of the `Derefer` pass. However, it just recreates the original places with derefs in the middle of the projection. Because `ProjectionElem::Deref` is intended to be removed completely in the future, this will not work forever. This PR introduces a `deref_chain` method that returns the places behind `DerefTemp` locals in a place and rewrites the move path code to use this. In the process, `UnDerefer` was merged into `MovePathLookup`. Now that move paths use the same places as in the MIR, the other uses of `UnDerefer` no longer require it. See rust-lang#98145 cc `@ouz-a` r? `@oli-obk`

rust-highfive assigned oli-obk Jun 15, 2022

rustbot added the T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. label Jun 15, 2022

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oli-obk reviewed Jun 20, 2022

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ouz-a force-pushed the some_branch branch from 9565104 to c4e65eb Compare June 20, 2022 16:37

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ouz-a force-pushed the some_branch branch 3 times, most recently from 9565104 to 2659f22 Compare June 21, 2022 12:45

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ouz-a force-pushed the some_branch branch from 508f189 to 1c521ce Compare June 21, 2022 14:08

ouz-a force-pushed the some_branch branch 4 times, most recently from 3243226 to aa91716 Compare June 22, 2022 19:37

ouz-a requested a review from oli-obk June 22, 2022 19:37

bors removed the S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. label Jun 23, 2022

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 Jul 12, 2022

bors added the merged-by-bors This PR was explicitly merged by bors. label Jul 13, 2022

bors merged commit 42bd138 into rust-lang:master Jul 13, 2022

rustbot added this to the 1.64.0 milestone Jul 13, 2022

bors mentioned this pull request Jul 13, 2022

Fix Dest Prop #96451

Merged

rustbot added the perf-regression Performance regression. label Jul 13, 2022

Dylan-DPC mentioned this pull request Jul 19, 2022

Regression on MIR queries #99473

Open

ouz-a mentioned this pull request Jul 20, 2022

Remove Rvalue::CopyForDeref #99499

Closed

celinval mentioned this pull request Jul 21, 2022

Update toolchain to nightly-2022-07-19 model-checking/kani#1399

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ouz-a mentioned this pull request Jul 24, 2022

Optimize UnDerefer #99667

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bors added a commit to rust-lang-ci/rust that referenced this pull request Jul 29, 2022

Auto merge of rust-lang#99667 - ouz-a:some_branch, r=oli-obk

7dfdd64

Optimize `UnDerefer` Addresses the performance [issues](rust-lang#98145 (comment)) faced here. r? `@oli-obk`

beepster4096 mentioned this pull request Jun 21, 2023

Rewrite UnDerefer #112882

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Pull Derefer before ElaborateDrops #98145

Pull Derefer before ElaborateDrops #98145

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Pull Derefer before ElaborateDrops #98145

Pull Derefer before ElaborateDrops #98145

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Instruction count

Max RSS (memory usage)

Cycles

Footnotes

oli-obk commented Jul 14, 2022

rylev commented Jul 19, 2022

Dylan-DPC commented Jul 19, 2022

ouz-a commented Jul 19, 2022