Make typeck a tcx method which calls typeck_root query by zetanumbers · Pull Request #154304 · rust-lang/rust

zetanumbers · 2026-03-24T11:07:25Z

Currently typeck query itself calls tcx.typeck(tcx.typeck_root_def_id(key)) if its key isn't a type-check root. I thought this might be an overhead and made typeck a tcx method which calls typeck_root query instead.

This is a step to simplify cache_on_disk_if query modifier.

@petrochenkov please run perf

petrochenkov · 2026-03-24T11:12:17Z

@bors try @rust-timer queue

[Experiement] Make typeck a tcx method which calls typeck_root query

zetanumbers · 2026-03-24T15:35:57Z

r? @petrochenkov

petrochenkov · 2026-03-24T16:41:40Z

@bors try @rust-timer queue

[Experiement] Make typeck a tcx method which calls typeck_root query

rust-bors · 2026-03-24T18:52:48Z

☀️ Try build successful (CI)
Build commit: 9e35fa9 (9e35fa9b6e285aa81be6f11080b4412a2f03249e, parent: 0312931d8c0ba1a28268a12c06202b68cbc65f76)

rust-timer · 2026-03-24T19:59:13Z

Finished benchmarking commit (9e35fa9): comparison URL.

Overall result: ❌✅ regressions and improvements - please read the text below

Benchmarking this pull request means it may be perf-sensitive – we'll automatically label it not fit for rolling up. You can override this, but we strongly advise not to, due to possible changes in compiler perf.

Next Steps: If you can justify the regressions found in this try perf run, please do so in sufficient writing along with @rustbot label: +perf-regression-triaged. If not, please fix the regressions and do another perf run. If its results are neutral or positive, the label will be automatically removed.

@bors rollup=never
@rustbot label: -S-waiting-on-perf +perf-regression

Instruction count

Our most reliable metric. Used to determine the overall result above. However, even this metric can be noisy.

	mean	range	count
Regressions ❌ (primary)	0.2%	[0.2%, 0.2%]	2
Regressions ❌ (secondary)	0.3%	[0.2%, 0.9%]	7
Improvements ✅ (primary)	-1.1%	[-6.0%, -0.2%]	38
Improvements ✅ (secondary)	-0.7%	[-2.0%, -0.3%]	13
All ❌✅ (primary)	-1.0%	[-6.0%, 0.2%]	40

Max RSS (memory usage)

Results (primary 3.2%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	3.2%	[2.1%, 4.3%]	2
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	3.2%	[2.1%, 4.3%]	2

Cycles

Results (primary -3.1%, secondary -2.9%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-3.1%	[-4.0%, -2.3%]	2
Improvements ✅ (secondary)	-2.9%	[-2.9%, -2.9%]	1
All ❌✅ (primary)	-3.1%	[-4.0%, -2.3%]	2

Binary size

Results (primary 0.1%, secondary 0.1%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	0.1%	[0.0%, 0.1%]	54
Regressions ❌ (secondary)	0.1%	[0.0%, 0.1%]	22
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.1%	[0.0%, 0.1%]	54

Bootstrap: 484.31s -> 485.406s (0.23%)
Artifact size: 394.79 MiB -> 396.97 MiB (0.55%)

zetanumbers · 2026-03-25T11:44:48Z

compiler/rustc_hir_typeck/src/lib.rs

-    if typeck_root_def_id != def_id {
-        return tcx.typeck(typeck_root_def_id);
-    }
+    assert!(!tcx.is_typeck_child(def_id.to_def_id()));


This assert might be a bit costly due its call to def_kind query.

This was debug_assert at the time rustc perf was run, so we should probably measure it again. I've changed it to non-debug assert to detect if some compiler dev would call it directly. If it increases compile time, I know how to make a TypeckRoot newtype over LocalDefId as an input to typeck_root to avoid this assertion. Or maybe I'm just too paranoid and it would be fine as debug too.

@petrochenkov

Make typeck a tcx method which calls typeck_root query Currently typeck query itself calls `tcx.typeck(tcx.typeck_root_def_id(key))` if its key isn't a type-check root. I thought this might be an overhead and made typeck a tcx method which calls typeck_root query instead. This is a step to simplify `cache_on_disk_if` query modifier. @petrochenkov please run perf

fmease · 2026-03-27T17:45:26Z

Average time of auto builds is 3h11 but this one is now at 5h25, clearly runaway / stuck.
@bors retry

rust-bors · 2026-03-27T17:45:28Z

❗ You can only retry pull requests that are approved and have a previously failed auto build.

Hint: There is currently a pending auto build on this PR. To cancel it, run @bors cancel.

fmease · 2026-03-27T17:45:42Z

@bors cancel

rust-bors · 2026-03-27T17:45:46Z

Auto build was cancelled. Cancelled workflows:

https://github.com/rust-lang/rust/actions/runs/23645882369

The next pull request likely to be tested is #154466.

rustbot · 2026-03-28T09:40:01Z

This PR was rebased onto a different main commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

zetanumbers · 2026-03-28T09:44:52Z

@rustbot ready

petrochenkov · 2026-03-29T05:50:16Z

@bors r+

rust-bors · 2026-03-29T05:50:19Z

📌 Commit 1792232 has been approved by petrochenkov

It is now in the queue for this repository.

rust-bors · 2026-03-29T22:49:03Z

☀️ Test successful - CI
Approved by: petrochenkov
Duration: 3h 11m 25s
Pushing a25435b to main...

github-actions · 2026-03-29T22:52:15Z

What is this?

This is an experimental post-merge analysis report that shows differences in test outcomes between the merged PR and its parent PR.

Comparing cd14b73 (parent) -> a25435b (this PR)

Test differences

Show 14 test diffs

14 doctest diffs were found. These are ignored, as they are noisy.

Test dashboard

Run

cargo run --manifest-path src/ci/citool/Cargo.toml -- \
    test-dashboard a25435bcf7cfc9b953d356eda3a51db8da9e3386 --output-dir test-dashboard

And then open test-dashboard/index.html in your browser to see an overview of all executed tests.

Job duration changes

pr-check-2: 37m 52s -> 45m 4s (+19.0%)
x86_64-gnu-distcheck: 2h 1m -> 2h 19m (+14.7%)
i686-gnu-nopt-1: 2h 4m -> 2h 22m (+14.5%)
x86_64-gnu-llvm-22-1: 1h 4m -> 1h 14m (+14.4%)
aarch64-apple: 2h 26m -> 2h 46m (+13.8%)
pr-check-1: 28m 18s -> 32m 10s (+13.7%)
i686-gnu-1: 2h 9m -> 2h 26m (+13.5%)
x86_64-msvc-ext3: 1h 44m -> 1h 57m (+12.7%)
x86_64-rust-for-linux: 46m 15s -> 51m 49s (+12.0%)
i686-gnu-2: 1h 32m -> 1h 42m (+11.8%)

How to interpret the job duration changes?

Job durations can vary a lot, based on the actual runner instance
that executed the job, system noise, invalidated caches, etc. The table above is provided
mostly for t-infra members, for simpler debugging of potential CI slow-downs.

rust-timer · 2026-03-29T23:30:21Z

Finished benchmarking commit (a25435b): comparison URL.

Overall result: ❌✅ regressions and improvements - please read the text below

Our benchmarks found a performance regression caused by this PR.
This might be an actual regression, but it can also be just noise.

Next Steps:

If the regression was expected or you think it can be justified,
please write a comment with sufficient written justification, and add
@rustbot label: +perf-regression-triaged to it, to mark the regression as triaged.
If you think that you know of a way to resolve the regression, try to create
a new PR with a fix for the regression.
If you do not understand the regression or you think that it is just noise,
you can ask the @rust-lang/wg-compiler-performance working group for help (members of this group
were already notified of this PR).

@rustbot label: +perf-regression
cc @rust-lang/wg-compiler-performance

Instruction count

Our most reliable metric. Used to determine the overall result above. However, even this metric can be noisy.

	mean	range	count
Regressions ❌ (primary)	0.2%	[0.2%, 0.2%]	3
Regressions ❌ (secondary)	0.3%	[0.3%, 0.3%]	6
Improvements ✅ (primary)	-1.1%	[-6.1%, -0.2%]	41
Improvements ✅ (secondary)	-0.7%	[-2.0%, -0.2%]	11
All ❌✅ (primary)	-1.0%	[-6.1%, 0.2%]	44

Max RSS (memory usage)

Results (primary -2.4%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-2.4%	[-2.4%, -2.4%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-2.4%	[-2.4%, -2.4%]	1

Cycles

Results (primary -2.9%, secondary -2.2%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-2.9%	[-3.7%, -2.1%]	2
Improvements ✅ (secondary)	-2.2%	[-2.2%, -2.2%]	1
All ❌✅ (primary)	-2.9%	[-3.7%, -2.1%]	2

Binary size

This benchmark run did not return any relevant results for this metric.

Bootstrap: 487.525s -> 486.086s (-0.30%)
Artifact size: 394.89 MiB -> 394.81 MiB (-0.02%)

rustbot added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Mar 24, 2026

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rust-bors bot pushed a commit that referenced this pull request Mar 24, 2026

Auto merge of #154304 - zetanumbers:typeck_root, r=<try>

6e65bd1

[Experiement] Make typeck a tcx method which calls typeck_root query

rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Mar 24, 2026

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rust-bors bot pushed a commit that referenced this pull request Mar 24, 2026

Auto merge of #154304 - zetanumbers:typeck_root, r=<try>

9e35fa9

[Experiement] Make typeck a tcx method which calls typeck_root query

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rustbot added perf-regression Performance regression. and removed S-waiting-on-perf Status: Waiting on a perf run to be completed. labels Mar 24, 2026

zetanumbers marked this pull request as ready for review March 25, 2026 09:15

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Mar 25, 2026

zetanumbers changed the title ~~[Experiement] Make typeck a tcx method which calls typeck_root query~~ Make typeck a tcx method which calls typeck_root query Mar 25, 2026

zetanumbers force-pushed the typeck_root branch from 9ab2a2a to 5b30212 Compare March 25, 2026 11:25

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zetanumbers commented Mar 25, 2026

View reviewed changes

rust-bors bot added the S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. label Mar 28, 2026

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rust-bors bot removed the S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. label Mar 28, 2026

zetanumbers added 4 commits March 28, 2026 12:38

Make typeck a tcx method which calls typeck_root query

94ed03a

Rename typeck into typeck_root in tests/ui

26c75df

Rename typeck into typeck_root in tests/incremental

5cf7376

fix tests/incremental/hashes

1792232

zetanumbers force-pushed the typeck_root branch from 569e5fb to 1792232 Compare March 28, 2026 09:39

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Mar 28, 2026

rust-bors bot 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 Mar 29, 2026

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rust-bors bot added merged-by-bors This PR was explicitly merged by bors. and removed S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Mar 29, 2026

rust-bors bot merged commit a25435b into rust-lang:main Mar 29, 2026
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rustbot added this to the 1.96.0 milestone Mar 29, 2026

rust-bors bot mentioned this pull request Mar 29, 2026

Add tracking of query call locations #154402

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Overall result: ❌✅ regressions and improvements - please read the text below

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Test differences

Job duration changes

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Overall result: ❌✅ regressions and improvements - please read the text below

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