LoongArch64 LSX fast-path for str.contains(&str)

[heiher]

Benchmark results with LLVM 21 on LA664:

OLD:
test bench_is_contained_in ... bench:          43.63 ns/iter (+/- 0.04)

NEW:
test bench_is_contained_in ... bench:          12.81 ns/iter (+/- 0.01)

[rustbot]

r? @tgross35

rustbot has assigned @tgross35.
They will have a look at your PR within the next two weeks and either review your PR or reassign to another reviewer.

Use r? to explicitly pick a reviewer

[heiher]

@bors r=tgross35

[bors]

@heiher: 🔑 Insufficient privileges: Not in reviewers

[tgross35]

Thanks!

@bors r+

[bors]

📌 Commit 1ceacf5 has been approved by tgross35

It is now in the queue for this repository.

[bors]

⌛ Testing commit 1ceacf5 with merge ba7e63b...

[bors]

☀️ Test successful - checks-actions
Approved by: tgross35
Pushing ba7e63b 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 686bc1c (parent) -> ba7e63b (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 ba7e63b63871a429533c189adbfb1d9a6337e000 --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. x86_64-apple-1: 6947.6s -> 10441.2s (50.3%)
2. dist-x86_64-apple: 7315.4s -> 10255.6s (40.2%)
3. dist-aarch64-apple: 7478.4s -> 5085.3s (-32.0%)
4. aarch64-msvc-1: 6960.6s -> 9107.5s (30.8%)
5. x86_64-gnu-distcheck: 8550.9s -> 7795.3s (-8.8%)
6. aarch64-apple: 4886.7s -> 5221.5s (6.9%)
7. tidy: 107.5s -> 114.4s (6.4%)
8. dist-riscv64-linux: 4780.5s -> 5080.3s (6.3%)
9. x86_64-apple-2: 3684.0s -> 3471.8s (-5.8%)
10. dist-aarch64-linux: 5635.6s -> 5899.6s (4.7%)

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 (ba7e63b): 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
Regressions ❌ (secondary)	0.9%	[0.9%, 1.0%]	6
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

Results (primary 5.6%)

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

	mean	range	count
Regressions ❌ (primary)	5.6%	[5.6%, 5.6%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	5.6%	[5.6%, 5.6%]	1

Cycles

Results (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)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-2.7%	[-3.1%, -2.3%]	2
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: 469.682s -> 469.063s (-0.13%)
Artifact size: 376.80 MiB -> 376.81 MiB (0.00%)

[lqd]

match-stress noise

@rustbot label: +perf-regression-triaged