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

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