Folder experiment: Monomorphize region resolver

[compiler-errors]

NOTE: This is one of a series of perf experiments that I've come up with while sick in bed. I'm assigning them to lqd b/c you're a good reviewer and you'll hopefully be awake when these experiments finish, lol.

r? lqd

This is actually two tweaks to the RegionFolder, monomorphizing its callback and accounting for flags to avoid folding unnecessarily.

[compiler-errors]

@bors try @rust-timer queue

[bors]

⌛ Trying commit 60b742d with merge 0ebb652...

[bors]

☀️ Try build successful - checks-actions
Build commit: 0ebb652 (0ebb652806a0269fb6ebfd6e57d7b8d025530124)

[rust-timer]

Finished benchmarking commit (0ebb652): comparison URL.

Overall result: ✅ improvements - no action needed

Benchmarking this pull request likely means that it is perf-sensitive, so we're automatically marking it as not fit for rolling up. While you can manually mark this PR as fit for rollup, we strongly recommend not doing so since this PR may lead to changes in compiler perf.

@bors rollup=never
@rustbot label: -S-waiting-on-perf -perf-regression

Instruction count

This is the most reliable metric that we have; it was used to determine the overall result at the top of this comment. However, even this metric can sometimes exhibit noise.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.3%	[-0.8%, -0.2%]	45
Improvements ✅ (secondary)	-0.7%	[-1.7%, -0.2%]	29
All ❌✅ (primary)	-0.3%	[-0.8%, -0.2%]	45

Max RSS (memory usage)

Results (primary 1.3%)

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	1.3%	[1.3%, 1.3%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	1.3%	[1.3%, 1.3%]	1

Cycles

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

Binary size

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

Bootstrap: 777.539s -> 779.926s (0.31%)
Artifact size: 365.91 MiB -> 366.17 MiB (0.07%)

[lqd]

This is Chef's kiss, but don't work while sick! Take care of yourself bestie.

Maybe it'd be interesting in the future to have a TypeFlags constructor that contains all the region-related variants to slightly simplify the check is here.

@bors r+

[bors]

📌 Commit 60b742d has been approved by lqd

It is now in the queue for this repository.

[Zalathar]

Scheduling: If the rollup #139344 fails, move on to this never PR instead of an iffy PR.

@bors p=1

[bors]

⌛ Testing commit 60b742d with merge f174fd7...

[bors]

☀️ Test successful - checks-actions
Approved by: lqd
Pushing f174fd7 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 9e14530 (parent) -> f174fd7 (this PR)

Test differences

No test diffs found

Job duration changes

1. dist-x86_64-musl: 7286.6s -> 7816.0s (7.3%)
2. dist-x86_64-freebsd: 4696.3s -> 4982.6s (6.1%)
3. i686-mingw-1: 7155.6s -> 7500.5s (4.8%)
4. x86_64-gnu-llvm-18-3: 6637.5s -> 6932.3s (4.4%)
5. x86_64-gnu-stable: 6577.5s -> 6864.2s (4.4%)
6. i686-gnu-nopt-1: 8287.3s -> 8644.6s (4.3%)
7. dist-i686-msvc: 7169.5s -> 7459.2s (4.0%)
8. x86_64-mingw-2: 6774.2s -> 7045.9s (4.0%)
9. dist-riscv64-linux: 5028.3s -> 5194.0s (3.3%)
10. dist-various-2: 3347.2s -> 3454.6s (3.2%)

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 (f174fd7): comparison URL.

Overall result: ✅ improvements - no action needed

@rustbot label: -perf-regression

Instruction count

This is the most reliable metric that we have; it was used to determine the overall result at the top of this comment. However, even this metric can sometimes exhibit noise.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.3%	[-0.7%, -0.2%]	34
Improvements ✅ (secondary)	-0.9%	[-1.6%, -0.2%]	19
All ❌✅ (primary)	-0.3%	[-0.7%, -0.2%]	34

Max RSS (memory usage)

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

Cycles

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

Binary size

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

Bootstrap: 773.774s -> 778.988s (0.67%)
Artifact size: 365.73 MiB -> 365.99 MiB (0.07%)