Split Bound index into Canonical and Bound #147138

jackh726 · 2025-09-28T23:49:24Z

See #t-types/trait-system-refactor > perf `async-closures/post-mono-higher-ranked-hang.rs` for context

Things compile and tests pass, but not sure if this actually solves the perf issue (edit: it does). Opening up this to do a perf (and maybe crater) run.

r? lcnr

jackh726 · 2025-09-29T02:09:52Z

@bors try @rust-timer queue

Split Bound index into Canonical and Bound

rust-bors · 2025-09-29T04:21:36Z

☀️ Try build successful (CI)
Build commit: 76676ec (76676ec14f76a781cb896ff6bc288cdebd16598d, parent: f957826bff7a68b267ce75b1ea56352aed0cca0a)

rust-timer · 2025-09-29T05:32:32Z

Finished benchmarking commit (76676ec): 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%	[0.1%, 0.3%]	9
Regressions ❌ (secondary)	0.2%	[0.2%, 0.3%]	2
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.3%	[-0.6%, -0.2%]	6
All ❌✅ (primary)	0.2%	[0.1%, 0.3%]	9

Max RSS (memory usage)

Results (primary -0.5%, secondary -4.0%)

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)	1.8%	[0.9%, 3.3%]	3
Improvements ✅ (primary)	-0.5%	[-0.5%, -0.5%]	1
Improvements ✅ (secondary)	-6.0%	[-11.2%, -1.2%]	9
All ❌✅ (primary)	-0.5%	[-0.5%, -0.5%]	1

Cycles

Results (primary 2.3%, secondary -1.6%)

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

	mean	range	count
Regressions ❌ (primary)	2.3%	[2.3%, 2.3%]	1
Regressions ❌ (secondary)	4.1%	[4.1%, 4.1%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-2.8%	[-4.8%, -1.1%]	5
All ❌✅ (primary)	2.3%	[2.3%, 2.3%]	1

Binary size

Results (primary 0.0%, secondary 0.0%)

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

	mean	range	count
Regressions ❌ (primary)	0.0%	[0.0%, 0.1%]	65
Regressions ❌ (secondary)	0.0%	[0.0%, 0.2%]	43
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.0%	[0.0%, 0.1%]	65

Bootstrap: 470.189s -> 470.608s (0.09%)
Artifact size: 387.63 MiB -> 387.72 MiB (0.02%)

compiler/rustc_infer/src/infer/canonical/canonicalizer.rs

lcnr · 2025-09-29T09:05:14Z

gotta say, I do not understand perf xd, I was so sure this would have a bigger perf impact on the new solver 😄

compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs

rustbot · 2025-09-29T18:01:41Z

Some changes occurred in compiler/rustc_sanitizers

cc @rcvalle

Some changes occurred in src/tools/clippy

cc @rust-lang/clippy

This PR changes rustc_public

cc @oli-obk, @celinval, @ouz-a

HIR ty lowering was modified

cc @fmease

jackh726 · 2025-09-29T19:12:22Z

@bors2 try @rust-timer queue

Split Bound index into Canonical and Bound

lcnr

some nits, then r=me

I don't think this needs a crater run 😁

View changes since this review

compiler/rustc_infer/src/infer/canonical/instantiate.rs

compiler/rustc_infer/src/infer/canonical/mod.rs

lcnr · 2025-09-29T19:08:51Z

compiler/rustc_middle/src/ty/context.rs


        let anon_bound_tys = (0..NUM_PREINTERNED_ANON_BOUND_TYS_I)
            .map(|i| {
                (0..NUM_PREINTERNED_ANON_BOUND_TYS_V)


please either check it yourself or leave a fixme here: we sohuld not have fr fewer bound tys/regions/consts so we could preintern fewer of them

I added a comment to NUM_PREINTERNED_ANON_BOUND_TYS_V, let me know your thoughts. tl;dr 90% 0 vars, 9% 1, usually not more than 3-5. But, given that it's heap allocated, I don't know what reducing it from 20 actually buys us.

yeah 🤔 20 is low enough to not really matter

i though we had like 400 of them (for regions at least) and i would expect to pretty much never have that many bound vars

compiler/rustc_next_trait_solver/src/canonical/canonicalizer.rs

lcnr · 2025-09-29T19:18:13Z

compiler/rustc_trait_selection/src/traits/select/mod.rs

+        assert!(
+            !predicate
+                .trait_ref
+                .has_type_flags(TypeFlags::HAS_CANONICAL_BOUND | TypeFlags::HAS_TY_BOUND)


how does this assert work? It would ICE for for<T> fn(T). I guess that doesn't exist yet (if ever)🤔

compiler/rustc_type_ir/src/binder.rs

compiler/rustc_type_ir/src/flags.rs

lcnr · 2025-09-29T19:23:04Z

can you add a next-solver revision to the previously very slow test

rust-bors · 2025-09-29T21:23:28Z

☀️ Try build successful (CI)
Build commit: f13b256 (f13b2569c4e269069c2a885e5834791a031a8bc0, parent: dc2c3564d273cf8ccce32dc4f47eaa27063bceb9)

rust-timer · 2025-09-29T22:32:55Z

Finished benchmarking commit (f13b256): 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%	[0.1%, 0.3%]	5
Regressions ❌ (secondary)	0.2%	[0.2%, 0.2%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.3%	[-0.6%, -0.2%]	5
All ❌✅ (primary)	0.2%	[0.1%, 0.3%]	5

Max RSS (memory usage)

Results (primary -3.7%, secondary -4.1%)

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)	1.8%	[1.1%, 2.7%]	3
Improvements ✅ (primary)	-3.7%	[-3.7%, -3.7%]	1
Improvements ✅ (secondary)	-6.1%	[-11.3%, -1.2%]	9
All ❌✅ (primary)	-3.7%	[-3.7%, -3.7%]	1

Cycles

Results (secondary 0.3%)

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)	3.5%	[2.8%, 4.3%]	3
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-2.9%	[-4.7%, -1.4%]	3
All ❌✅ (primary)	-	-	0

Binary size

Results (primary 0.0%, secondary 0.0%)

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

	mean	range	count
Regressions ❌ (primary)	0.0%	[0.0%, 0.1%]	65
Regressions ❌ (secondary)	0.0%	[0.0%, 0.2%]	43
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.0%	[0.0%, 0.1%]	65

Bootstrap: 470.099s -> 472.362s (0.48%)
Artifact size: 387.67 MiB -> 387.70 MiB (0.01%)

lcnr

r=me after you fix CI :3

View changes since this review

jackh726 · 2025-09-30T20:06:53Z

@bors r=lcnr

bors · 2025-09-30T20:06:56Z

📌 Commit d1bbd39 has been approved by lcnr

It is now in the queue for this repository.

bors · 2025-10-02T08:09:37Z

⌛ Testing commit d1bbd39 with merge 4b9c62b...

bors · 2025-10-02T11:13:29Z

☀️ Test successful - checks-actions
Approved by: lcnr
Pushing 4b9c62b to master...

github-actions · 2025-10-02T11:16:29Z

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 42b384e (parent) -> 4b9c62b (this PR)

Test differences

Show 48 test diffs

Stage 1

[ui] tests/ui/async-await/async-closures/post-mono-higher-ranked-hang.rs: pass -> [missing] (J0)
[ui] tests/ui/async-await/async-closures/post-mono-higher-ranked-hang.rs#current: [missing] -> pass (J0)
[ui] tests/ui/async-await/async-closures/post-mono-higher-ranked-hang.rs#next: [missing] -> pass (J0)

Stage 2

[ui] tests/ui/async-await/async-closures/post-mono-higher-ranked-hang.rs: pass -> [missing] (J1)
[ui] tests/ui/async-await/async-closures/post-mono-higher-ranked-hang.rs#current: [missing] -> pass (J1)
[ui] tests/ui/async-await/async-closures/post-mono-higher-ranked-hang.rs#next: [missing] -> pass (J1)

Additionally, 42 doctest diffs were found. These are ignored, as they are noisy.

Job group index

Test dashboard

Run

cargo run --manifest-path src/ci/citool/Cargo.toml -- \
    test-dashboard 4b9c62b4da3e17cee99d3d2052f1c576b188e2a8 --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

dist-apple-various: 4295.3s -> 3621.4s (-15.7%)
x86_64-gnu-llvm-20: 2413.1s -> 2749.3s (13.9%)
x86_64-rust-for-linux: 2701.2s -> 3033.8s (12.3%)
dist-aarch64-apple: 7751.7s -> 6884.4s (-11.2%)
dist-ohos-aarch64: 4587.6s -> 4075.3s (-11.2%)
dist-aarch64-msvc: 6621.4s -> 5909.4s (-10.8%)
dist-x86_64-apple: 7064.5s -> 7770.4s (10.0%)
x86_64-gnu: 6346.3s -> 6911.3s (8.9%)
x86_64-gnu-llvm-20-3: 6010.8s -> 6474.0s (7.7%)
aarch64-msvc-1: 7163.9s -> 6623.8s (-7.5%)

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 · 2025-10-02T12:24:44Z

Finished benchmarking commit (4b9c62b): 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%	[0.1%, 0.4%]	7
Regressions ❌ (secondary)	0.1%	[0.1%, 0.2%]	11
Improvements ✅ (primary)	-1.0%	[-2.8%, -0.1%]	4
Improvements ✅ (secondary)	-0.3%	[-1.1%, -0.0%]	11
All ❌✅ (primary)	-0.3%	[-2.8%, 0.4%]	11

Max RSS (memory usage)

Results (primary -0.8%, secondary -4.5%)

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

	mean	range	count
Regressions ❌ (primary)	0.6%	[0.6%, 0.6%]	1
Regressions ❌ (secondary)	1.2%	[1.2%, 1.2%]	1
Improvements ✅ (primary)	-0.9%	[-1.4%, -0.6%]	9
Improvements ✅ (secondary)	-4.9%	[-11.2%, -1.2%]	13
All ❌✅ (primary)	-0.8%	[-1.4%, 0.6%]	10

Cycles

Results (primary -2.8%, 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)	-2.8%	[-2.8%, -2.8%]	1
Improvements ✅ (secondary)	-2.2%	[-3.3%, -1.1%]	6
All ❌✅ (primary)	-2.8%	[-2.8%, -2.8%]	1

Binary size

Results (primary 0.0%, secondary 0.0%)

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

	mean	range	count
Regressions ❌ (primary)	0.0%	[0.0%, 0.1%]	70
Regressions ❌ (secondary)	0.0%	[0.0%, 0.2%]	43
Improvements ✅ (primary)	-1.1%	[-1.1%, -1.1%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.0%	[-1.1%, 0.1%]	71

Bootstrap: 471.941s -> 471.25s (-0.15%)
Artifact size: 387.76 MiB -> 387.76 MiB (-0.00%)

panstromek · 2025-10-06T15:19:36Z

perf triage:

Improvements outweigh regressions, but some of those improvements are noise (clap-derive and syn). Main regressions match pre-merge results, so I assume this was deemed acceptable as a part of work on new solver, but I don't see any explicit justification.

@rustbot label: +perf-regression-triaged

Split Bound index into Canonical and Bound See [#t-types/trait-system-refactor > perf &rust-lang#96;async-closures/post-mono-higher-ranked-hang.rs&rust-lang#96;](https://rust-lang.zulipchat.com/#narrow/channel/364551-t-types.2Ftrait-system-refactor/topic/perf.20.60async-closures.2Fpost-mono-higher-ranked-hang.2Ers.60/with/541535613) for context Things compile and tests pass, but not sure if this actually solves the perf issue (edit: it does). Opening up this to do a perf (and maybe crater) run. r? lcnr

jackh726 · 2025-10-06T16:27:22Z

@panstromek

Perf here is somewhat irrelevant, since this change fixes a hang with the next solver that isn't covered by the test suite.

rustbot assigned lcnr Sep 28, 2025

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Auto merge of #147138 - jackh726:split-canonical-bound, r=<try>

76676ec

Split Bound index into Canonical and Bound

rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Sep 29, 2025

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rust-cloud-vms bot force-pushed the split-canonical-bound branch from 3d24484 to 1372123 Compare September 29, 2025 04:30

rustbot added the T-clippy Relevant to the Clippy team. label Sep 29, 2025

rustbot added perf-regression Performance regression. and removed S-waiting-on-perf Status: Waiting on a perf run to be completed. labels Sep 29, 2025

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jackh726 marked this pull request as ready for review September 29, 2025 18:01

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 Sep 29, 2025

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Auto merge of #147138 - jackh726:split-canonical-bound, r=<try>

f13b256

Split Bound index into Canonical and Bound

rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Sep 29, 2025

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jackh726 force-pushed the split-canonical-bound branch from f0434cc to 050d60f Compare September 30, 2025 07:18

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Split Bound into Canonical and Bound

d1bbd39

jackh726 force-pushed the split-canonical-bound branch from 050d60f to d1bbd39 Compare September 30, 2025 16:58

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 Sep 30, 2025

lcnr mentioned this pull request Oct 1, 2025

[DO NOT MERGE] bootstrap with -Znext-solver=globally #133502

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bors added the merged-by-bors This PR was explicitly merged by bors. label Oct 2, 2025

bors merged commit 4b9c62b into rust-lang:master Oct 2, 2025
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rustbot added this to the 1.92.0 milestone Oct 2, 2025

lcnr mentioned this pull request Oct 2, 2025

ui tests take a very long time rust-lang/trait-system-refactor-initiative#192

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jackh726 deleted the split-canonical-bound branch October 2, 2025 13:23

github-actions bot mentioned this pull request Oct 3, 2025

Toolchain upgrade to nightly-2025-10-09 flux-rs/flux#1271

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rustbot added the perf-regression-triaged The performance regression has been triaged. label Oct 6, 2025

Split Bound index into Canonical and Bound #147138

Split Bound index into Canonical and Bound #147138

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

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

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Test differences

Stage 1

Stage 2

Job duration changes

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

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