early return on duplicate span lowerings

[jdonszelmann]

@bors2 try

[rust-bors[bot]]

:hourglass: Trying commit 7e0afd18071b0def770e413282643d68f1a54946 with merge 591267e0f211c94f76f16726505d96a61297aa30…

To cancel the try build, run the command @bors try cancel.

Workflow: https://github.com/rust-lang/rust/actions/runs/19468782916

[jdonszelmann]

@rust-timer queue

[rust-timer]

Awaiting bors try build completion.

@rustbot label: +S-waiting-on-perf

[jdonszelmann]

@bors try cancel

[rust-bors[bot]]

Try build cancelled. Cancelled workflows:

• https://github.com/rust-lang/rust/actions/runs/19468782916

[jdonszelmann]

@bors2 try @rust-timer queue

[rust-timer]

This pull request was already queued before and is awaiting a try build to finish.

[rust-bors[bot]]

:hourglass: Trying commit 7e0afd18071b0def770e413282643d68f1a54946 with merge 3fbec87b43d00a75980a5b8d6f070bb97d40cee0…

To cancel the try build, run the command @bors try cancel.

Workflow: https://github.com/rust-lang/rust/actions/runs/19469045712

[jdonszelmann]

@bors try cancel

[rust-bors[bot]]

Try build cancelled. Cancelled workflows:

• https://github.com/rust-lang/rust/actions/runs/19469045712

[jdonszelmann]

@bors2 try @rust-timer queue

[rust-timer]

This pull request was already queued before and is awaiting a try build to finish.

[rust-bors[bot]]

:hourglass: Trying commit e9ad039d29d9c65414532481e9283e3cb92a933f with merge a0c110f657f885a3fe1c9415cbffa402f2be5cb3…

To cancel the try build, run the command @bors try cancel.

Workflow: https://github.com/rust-lang/rust/actions/runs/19469111989

[rust-bors[bot]]

:sunny: Try build successful (CI) Build commit: a0c110f657f885a3fe1c9415cbffa402f2be5cb3 (a0c110f657f885a3fe1c9415cbffa402f2be5cb3, parent: f9e7961506a97b318ad4815b8ce94bb045562f89)

[rust-timer]

Queued a0c110f657f885a3fe1c9415cbffa402f2be5cb3 with parent f9e7961506a97b318ad4815b8ce94bb045562f89, future comparison URL. There is currently 1 preceding artifact in the queue. It will probably take at least ~1.6 hours until the benchmark run finishes.

[rust-timer]

Finished benchmarking commit (a0c110f657f885a3fe1c9415cbffa402f2be5cb3): 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)	0.1%	[0.1%, 0.1%]	2
Regressions ❌ (secondary)	0.2%	[0.2%, 0.2%]	7
Improvements ✅ (primary)	-0.8%	[-2.9%, -0.1%]	4
Improvements ✅ (secondary)	-0.6%	[-0.6%, -0.6%]	3
All ❌✅ (primary)	-0.5%	[-2.9%, 0.1%]	6

Max RSS (memory usage)

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

Cycles

Results (primary -2.4%, secondary 2.7%)

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)	2.7%	[2.7%, 2.7%]	1
Improvements ✅ (primary)	-2.4%	[-2.4%, -2.4%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-2.4%	[-2.4%, -2.4%]	1

Binary size

Results (primary -1.1%)

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)	-	-	0
Improvements ✅ (primary)	-1.1%	[-1.1%, -1.1%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-1.1%	[-1.1%, -1.1%]	1

Bootstrap: 471.624s -> 473.081s (0.31%) Artifact size: 388.73 MiB -> 388.78 MiB (0.01%)

[jdonszelmann]

welp, that seems worth it

[jdonszelmann]

lemme clean it up and mark it ready

[jdonszelmann]

r? @oli-obk

[rustbot]

oli-obk is not on the review rotation at the moment. They may take a while to respond.

[WaffleLapkin]

@bors r+

[bors]

:pushpin: Commit 0087253015d1191b97b5e312c2409e008db87ed6 has been approved by WaffleLapkin

It is now in the queue for this repository.

[bors]

:hourglass: Testing commit 0087253015d1191b97b5e312c2409e008db87ed6 with merge fa1f706fbd0fd1c02763ecb28915bf23c860cb32...

[bors]

:sunny: Test successful - checks-actions Approved by: WaffleLapkin Pushing fa1f706fbd0fd1c02763ecb28915bf23c860cb32 to main...

[github-actions[bot]]

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 1d6c526bb010900bc1fd4c45c4ef0307b5150583 (parent) -> fa1f706fbd0fd1c02763ecb28915bf23c860cb32 (this PR)

Test differences

Show 2 test diffs

2 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 fa1f706fbd0fd1c02763ecb28915bf23c860cb32 --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

1. aarch64-apple: 8994.2s -> 7065.9s (-21.4%)
2. dist-aarch64-apple: 6440.3s -> 7552.3s (+17.3%)
3. dist-x86_64-apple: 7541.4s -> 6608.8s (-12.4%)
4. i686-gnu-2: 5270.3s -> 5737.9s (+8.9%)
5. aarch64-gnu-llvm-20-2: 2315.4s -> 2116.6s (-8.6%)
6. test-various: 6542.9s -> 6042.8s (-7.6%)
7. x86_64-gnu: 6512.8s -> 7006.1s (+7.6%)
8. aarch64-msvc-1: 7198.3s -> 6662.3s (-7.4%)
9. dist-apple-various: 3671.0s -> 3909.5s (+6.5%)
10. pr-check-2: 2156.0s -> 2290.2s (+6.2%)

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]

Finished benchmarking commit (fa1f706fbd0fd1c02763ecb28915bf23c860cb32): comparison URL.

Overall result: ❌ regressions - 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)	0.3%	[0.1%, 0.8%]	70
Regressions ❌ (secondary)	0.4%	[0.0%, 0.8%]	73
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.3%	[0.1%, 0.8%]	70

Max RSS (memory usage)

Results (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)	-	-	0
Improvements ✅ (secondary)	-2.2%	[-2.2%, -2.2%]	1
All ❌✅ (primary)	-	-	0

Cycles

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

Binary size

Results (primary 0.0%, 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)	0.0%	[0.0%, 0.0%]	27
Regressions ❌ (secondary)	0.1%	[0.0%, 0.1%]	5
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.0%	[0.0%, 0.0%]	27

Bootstrap: 470.852s -> 468.293s (-0.54%) Artifact size: 388.93 MiB -> 389.00 MiB (0.02%)

[nnethercote]

@jdonszelmann Final version results are very different to the original. Revert?

[jdonszelmann]

that's wild, I cannot imagine this to be anything but a perf improvement

[jdonszelmann]

are we sure this is accurate? I'm getting 502s (@kobzol) on a bunch of the detailed pages

[jdonszelmann]

I guess I'll at least prep a revert yea