stdarch subtree update

[Kobzol]

Subtree update of stdarch to rust-lang/stdarch@5531955.

Created using https://github.com/rust-lang/josh-sync.

I saw that there were non-trivial changes made to std_detect in stdarch recently. So I want to get them merged here before we move forward with #143412.

r? @folkertdev

[rustbot]

stdarch is developed in its own repository. If possible, consider making this change to rust-lang/stdarch instead.

cc @Amanieu, @folkertdev, @sayantn

[folkertdev]

we usually don't rollup these right?

@bors r+ rollup=never

[bors]

📌 Commit 9b7d31c has been approved by folkertdev

It is now in the queue for this repository.

[Kobzol]

I think we could, but doesn't really matter.

[Kobzol]

I'm gonna go ahead and bump this one up, so that we don't get more conflicts with stdarch, the move of std_detect into rustc is potentially conflict-prone.

@bors p=1

[bors]

⌛ Testing commit 9b7d31c with merge 2e53675...

[bors]

☀️ Test successful - checks-actions
Approved by: folkertdev
Pushing 2e53675 to master...

[github-actions]

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 35487a2 (parent) -> 2e53675 (this PR)

Test differences

Show 16 test diffs

16 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 2e5367566819ca7878baa9600ae7a93eb0e37bbf --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: 4357.9s -> 6596.7s (51.4%)
2. dist-x86_64-apple: 13292.7s -> 10898.7s (-18.0%)
3. x86_64-gnu-llvm-20-2: 5535.7s -> 6364.8s (15.0%)
4. dist-apple-various: 9840.3s -> 8476.8s (-13.9%)
5. dist-aarch64-apple: 6139.0s -> 5326.0s (-13.2%)
6. dist-x86_64-netbsd: 5217.7s -> 4615.6s (-11.5%)
7. dist-ohos-armv7: 4210.1s -> 3823.2s (-9.2%)
8. dist-x86_64-windows-gnullvm: 5912.3s -> 5405.7s (-8.6%)
9. dist-powerpc64-linux: 5397.8s -> 4946.4s (-8.4%)
10. x86_64-apple-2: 4673.6s -> 4286.4s (-8.3%)

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 (2e53675): comparison URL.

Overall result: no relevant changes - no action needed

@rustbot label: -perf-regression

Instruction count

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

Max RSS (memory usage)

Results (secondary -3.7%)

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)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-3.7%	[-4.4%, -2.9%]	3
All ❌✅ (primary)	-	-	0

Cycles

Results (secondary 2.8%)

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)	2.8%	[2.2%, 3.2%]	3
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: 465.187s -> 465.103s (-0.02%)
Artifact size: 374.60 MiB -> 374.58 MiB (-0.00%)