Fix regression in the MIR lowering of or-patterns #127028

Nadrieril · 2024-06-27T09:30:18Z

In #126553 I made a silly indexing mistake and regressed the MIR lowering of or-patterns. This fixes it.

r? @compiler-errors because I'd like this to be merged quickly 🙏

Nadrieril · 2024-06-27T09:32:48Z

compiler/rustc_mir_build/src/build/matches/mod.rs

+            if expand_until != 0 {
+                expand_until = i + 1;
+            }


The idea was "include as many candidates until we find a candidate where we should stop" but I forgot to keep incrementing the index so I cut off candidates I should have included. As you can see in the test file, this created unnecessary extra SwitchInts.

matthewjasper · 2024-07-09T09:17:32Z

r? @matthewjasper
@bors r+

bors · 2024-07-09T09:17:34Z

📌 Commit 834f043 has been approved by matthewjasper

It is now in the queue for this repository.

…matthewjasper Fix regression in the MIR lowering of or-patterns In rust-lang#126553 I made a silly indexing mistake and regressed the MIR lowering of or-patterns. This fixes it. r? `@compiler-errors` because I'd like this to be merged quickly 🙏

…iaskrgr Rollup of 8 pull requests Successful merges: - rust-lang#127028 (Fix regression in the MIR lowering of or-patterns) - rust-lang#127091 (impl FusedIterator and a size hint for the error sources iter) - rust-lang#127358 (Automatically taint when reporting errors from ItemCtxt) - rust-lang#127382 (Use verbose style when suggesting changing `const` with `let`) - rust-lang#127397 (fix interleaved output in the default panic hook when multiple threads panic simultaneously) - rust-lang#127484 (`#[doc(alias)]`'s doc: say that ASCII spaces are allowed) - rust-lang#127496 (Update `f16`/`f128` FIXMEs that needed `(NEG_)INFINITY`) - rust-lang#127508 (small search graph refactor) r? `@ghost` `@rustbot` modify labels: rollup

bors · 2024-07-09T16:34:02Z

⌛ Testing commit 834f043 with merge 9dcaa7f...

bors · 2024-07-09T18:49:12Z

☀️ Test successful - checks-actions
Approved by: matthewjasper
Pushing 9dcaa7f to master...

Nadrieril · 2024-07-09T19:44:11Z

Ty!

rust-timer · 2024-07-10T00:14:27Z

Finished benchmarking commit (9dcaa7f): comparison URL.

Overall result: ❌ regressions - ACTION NEEDED

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
cc @rust-lang/wg-compiler-performance

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	0.7%	[0.3%, 1.2%]	3
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.7%	[0.3%, 1.2%]	3

Max RSS (memory usage)

Results (primary 0.4%)

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	3.9%	[2.5%, 6.9%]	4
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-6.7%	[-7.8%, -5.6%]	2
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.4%	[-7.8%, 6.9%]	6

Cycles

Results (primary 1.1%, secondary -2.3%)

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	1.1%	[1.0%, 1.1%]	2
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-2.3%	[-3.4%, -1.2%]	2
All ❌✅ (primary)	1.1%	[1.0%, 1.1%]	2

Binary size

Results (primary 0.0%)

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	0.1%	[0.0%, 0.6%]	11
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.1%	[-0.1%, -0.0%]	18
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.0%	[-0.1%, 0.6%]	29

Bootstrap: 701.812s -> 702.397s (0.08%)
Artifact size: 328.73 MiB -> 328.67 MiB (-0.02%)

…atthewjasper match lowering: Clarify the main loop of the algorithm Now that we expand or-patterns in a single place in the algorithm, we can move it (back) to the main part of the loop. This makes the call-graph of the main loop rather simple: `match_candidates` has three branches that each call back to `match_candidates`. The remaining tricky part is `finalize_or_candidate`. I also factored out the whole "process a prefix of the candidates then process the rest" thing which I think helps legibility. The first two commits are a fix for an indexing mistake I introduced in rust-lang#126553, already sumitted in rust-lang#127028 but feel free to merge this first. r? `@matthewjasper`

Rollup merge of rust-lang#127164 - Nadrieril:clean-lowering-loop, r=matthewjasper match lowering: Clarify the main loop of the algorithm Now that we expand or-patterns in a single place in the algorithm, we can move it (back) to the main part of the loop. This makes the call-graph of the main loop rather simple: `match_candidates` has three branches that each call back to `match_candidates`. The remaining tricky part is `finalize_or_candidate`. I also factored out the whole "process a prefix of the candidates then process the rest" thing which I think helps legibility. The first two commits are a fix for an indexing mistake I introduced in rust-lang#126553, already sumitted in rust-lang#127028 but feel free to merge this first. r? `@matthewjasper`

rylev · 2024-07-17T13:08:41Z

Given this is a correctness fix, and the regressions seem in line with previous historical performance (i.e., it regressed back to a previous baseline), I think it's safe to call this triaged. Let me know if anyone disagrees.

@rustbot label: +perf-regression-triaged

Nadrieril added 2 commits June 27, 2024 11:26

Add test

5df6f72

Fix expansion of or-patterns

834f043

rustbot assigned compiler-errors Jun 27, 2024

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Jun 27, 2024

Nadrieril commented Jun 27, 2024

View reviewed changes

Nadrieril changed the title ~~Fix expansion of or-patterns~~ Fix regression in the codegen of or-patterns Jun 27, 2024

This was referenced Jun 27, 2024

Mad rustc update AeneasVerif/charon#272

Merged

Fix match control-flow of or-patterns AeneasVerif/charon#273

Closed

Nadrieril changed the title ~~Fix regression in the codegen of or-patterns~~ Fix regression in the MOR lowering of or-patterns Jun 27, 2024

Nadrieril changed the title ~~Fix regression in the MOR lowering of or-patterns~~ Fix regression in the MIR lowering of or-patterns Jun 27, 2024

Nadrieril mentioned this pull request Jun 30, 2024

match lowering: Clarify the main loop of the algorithm #127164

Merged

rustbot assigned matthewjasper and unassigned compiler-errors Jul 9, 2024

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-review Status: Awaiting review from the assignee but also interested parties. labels Jul 9, 2024

matthiaskrgr mentioned this pull request Jul 9, 2024

Rollup of 8 pull requests #127519

Closed

bors added the merged-by-bors This PR was explicitly merged by bors. label Jul 9, 2024

bors merged commit 9dcaa7f into rust-lang:master Jul 9, 2024
7 checks passed

rustbot added this to the 1.81.0 milestone Jul 9, 2024

Nadrieril deleted the fix-or-pat-expansion branch July 9, 2024 19:44

rustbot added the perf-regression Performance regression. label Jul 10, 2024

rustbot added the perf-regression-triaged The performance regression has been triaged. label Jul 17, 2024

Nadrieril mentioned this pull request Aug 12, 2024

Bump rustc version hacspec/hax#838

Merged

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Fix regression in the MIR lowering of or-patterns #127028

Fix regression in the MIR lowering of or-patterns #127028

Nadrieril commented Jun 27, 2024 •

edited

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Nadrieril Jun 27, 2024

matthewjasper commented Jul 9, 2024

bors commented Jul 9, 2024

bors commented Jul 9, 2024

bors commented Jul 9, 2024

Nadrieril commented Jul 9, 2024

rust-timer commented Jul 10, 2024

rylev commented Jul 17, 2024

Fix regression in the MIR lowering of or-patterns #127028

Fix regression in the MIR lowering of or-patterns #127028

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Nadrieril commented Jun 27, 2024 • edited Loading

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matthewjasper commented Jul 9, 2024

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Nadrieril commented Jul 9, 2024

rust-timer commented Jul 10, 2024

Overall result: ❌ regressions - ACTION NEEDED

Instruction count

Max RSS (memory usage)

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Binary size

rylev commented Jul 17, 2024

Nadrieril commented Jun 27, 2024 •

edited

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