Usually avoid the sort in WrappingRange::smallest_range_containing

[scottmcm]

I wasn't planning on touching this again, but I had a shower thought: we've been sorting these for a while because that's better than doing a quadratic check for usable wraparound ranges, but actually we often don't need to.

So long as the obvious min..=max range is small enough, we don't need to bother even looking for a wrapping range!

Now, I don't think this code is particularly hot -- you'd need lots of enums or particularly big ones before it would really matter -- but this does let us short-circuit for even fairly complex enums like mem::alignment.

---

• I did not use an LLM to create a change in this PR.

[scottmcm]

@bors try @rust-timer queue

[rust-bors]

☀️ Try build successful (CI)
Build commit: d0d0b8b (d0d0b8bc325afb707fbc76fb45f437b5d32c6ce4)
Base parent: 88f7399 (88f7399cb4912680976e1c342ea7661b9dc84940)

[rust-timer]

Finished benchmarking commit (d0d0b8b): comparison URL.

Overall result: ❌✅ regressions and improvements - please read:

Benchmarking means the PR may be perf-sensitive. It's automatically marked not fit for rolling up. Overriding is possible but disadvised: it risks changing compiler perf.

Next, please: If you can, justify the regressions found in this try perf run in writing along with @rustbot label: +perf-regression-triaged. If not, fix the regressions and do another perf run. Neutral or positive results will clear the label automatically.

@bors rollup=never rustc-perf
@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
Regressions ❌ (secondary)	0.6%	[0.5%, 0.6%]	3
Improvements ✅ (primary)	-0.4%	[-0.4%, -0.4%]	1
Improvements ✅ (secondary)	-0.4%	[-0.5%, -0.3%]	6
All ❌✅ (primary)	-0.4%	[-0.4%, -0.4%]	1

Max RSS (memory usage)

Results (primary 1.1%, secondary -0.5%)

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

	mean	range	count
Regressions ❌ (primary)	4.9%	[4.9%, 4.9%]	1
Regressions ❌ (secondary)	3.1%	[0.4%, 5.8%]	2
Improvements ✅ (primary)	-2.7%	[-2.7%, -2.7%]	1
Improvements ✅ (secondary)	-1.1%	[-5.7%, -0.4%]	12
All ❌✅ (primary)	1.1%	[-2.7%, 4.9%]	2

Cycles

Results (secondary -0.7%)

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)	0.9%	[0.4%, 2.3%]	8
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-1.4%	[-6.9%, -0.4%]	19
All ❌✅ (primary)	-	-	0

Binary size

This perf run didn't have relevant results for this metric.

Bootstrap: 460.09s -> 458.727s (-0.30%)
Artifact size: 398.62 MiB -> 398.67 MiB (0.01%)

[rustbot]

r? @folkertdev

rustbot has assigned @folkertdev.
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

Why was this reviewer chosen?

The reviewer was selected based on:

• Owners of files modified in this PR: codegen, compiler
• codegen, compiler expanded to 75 candidates
• Random selection from 19 candidates

[folkertdev]

@bors r+

[rust-bors]

📌 Commit 9704e63 has been approved by folkertdev

It is now in the queue for this repository.

[JonathanBrouwer]

@bors p=6 scheduling before rollup since the rollup is still small

[rust-bors]

☀️ Test successful - CI
Approved by: folkertdev
Duration: 2h 58m 27s
Pushing 5c16940 to main...

[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 153ecc4 (parent) -> 5c16940 (this PR)

Test differences

Show 4 test diffs

4 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 5c16940f0db74f04a309b547ebac613e16aef3ba --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. i686-msvc-2: 1h 28m -> 2h 6m (+43.7%)
2. x86_64-gnu-parallel-frontend: 2h 11m -> 1h 21m (-38.2%)
3. dist-x86_64-freebsd: 1h -> 1h 23m (+37.5%)
4. dist-arm-linux-musl: 1h 47m -> 1h 7m (-37.0%)
5. i686-gnu-1: 2h 17m -> 1h 28m (-35.8%)
6. x86_64-gnu-llvm-21: 41m 8s -> 55m 25s (+34.7%)
7. dist-sparcv9-solaris: 1h 10m -> 1h 34m (+33.4%)
8. x86_64-rust-for-linux: 38m 25s -> 50m 57s (+32.6%)
9. x86_64-gnu-llvm-22-2: 1h 33m -> 1h 6m (-29.6%)
10. dist-x86_64-netbsd: 1h 24m -> 59m 46s (-29.1%)

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 (5c16940): comparison URL.

Overall result: ❌ regressions - no action needed

@rustbot label: -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)	0.4%	[0.4%, 0.4%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.4%	[0.4%, 0.4%]	1

Max RSS (memory usage)

Results (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
Regressions ❌ (secondary)	1.1%	[0.6%, 2.7%]	6
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-1.2%	[-3.0%, -0.4%]	6
All ❌✅ (primary)	-	-	0

Cycles

Results (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
Regressions ❌ (secondary)	1.7%	[0.5%, 4.7%]	5
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.8%	[-1.3%, -0.4%]	14
All ❌✅ (primary)	-	-	0

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
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.1%	[-0.1%, -0.0%]	15
Improvements ✅ (secondary)	-0.1%	[-0.1%, -0.0%]	15
All ❌✅ (primary)	-0.1%	[-0.1%, -0.0%]	15

Bootstrap: 458.036s -> 461.157s (0.68%)
Artifact size: 398.61 MiB -> 398.54 MiB (-0.02%)

[scottmcm]

Ah, any perf change here was probably just noise, I guess -- +0.4 after merge on the exact same benchmark that was -0.4 before the merge.