Use a reduced recursion limit in the MIR inliner's cycle breaker

[saethlin]

This probably papers over #128887, but primarily I'm opening this PR because multiple compiler people have thought about making this change which probably means it's a good idea.

r? compiler-errors

[rustbot]

Some changes occurred to MIR optimizations

cc @rust-lang/wg-mir-opt

[compiler-errors]

@bors r+ rollup=never

[bors]

📌 Commit 950437a has been approved by compiler-errors

It is now in the queue for this repository.

[compiler-errors]

Ideally we'd have a UI test for this, but presumably it depends too much on the def path ordering hack? Or were you just too lazy to add a test, @saethlin?

[saethlin]

I'm too lazy, but also you're right that a UI test would be probabilistic, though we have at least one of those already.

[compiler-errors]

@saethlin: In the future please make sure to bundle observable changes to the compiler with a UI test if possible, even if it's probabilistic :^)

[saethlin]

I can probably add a ui test to this tomorrow

[wesleywiser]

@bors p=1

Candidate for backport to 1.81.

[apiraino]

Beta backport accepted as per compiler team on Zulip. A backport PR will be authored by the release team at the end of the current development cycle.

@rustbot label +beta-accepted

[bors]

⌛ Testing commit 950437a with merge 784d444...

[bors]

☀️ Test successful - checks-actions
Approved by: compiler-errors
Pushing 784d444 to master...

[rust-timer]

Finished benchmarking commit (784d444): comparison URL.

Overall result: ✅ improvements - no action needed

@rustbot label: -perf-regression

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.7%	[-0.7%, -0.7%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-0.7%	[-0.7%, -0.7%]	1

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: missing data
Artifact size: 338.70 MiB -> 338.73 MiB (0.01%)

[Kobzol]

Something weird has happened here. Bootstrap was not benchmarked and only a subset of the normal benchmarks was executed. In the following merge, bootstrap was measured fine, but we also only got a subset of results, because it was compared with this PR. The next merged PR should show us whether it was a transient issue.

[rust-timer]

Finished benchmarking commit (784d444): comparison URL.

Overall result: ✅ improvements - no action needed

@rustbot label: -perf-regression

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.8%	[-0.8%, -0.8%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-0.8%	[-0.8%, -0.8%]	1

Max RSS (memory usage)

Results (primary -2.2%, secondary 0.9%)

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)	-	-	0
Regressions ❌ (secondary)	0.9%	[0.9%, 0.9%]	1
Improvements ✅ (primary)	-2.2%	[-2.2%, -2.2%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-2.2%	[-2.2%, -2.2%]	1

Cycles

Results (secondary -1.7%)

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)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-1.7%	[-1.7%, -1.7%]	1
All ❌✅ (primary)	-	-	0

Binary size

Results (secondary -0.0%)

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)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.0%	[-0.0%, -0.0%]	1
All ❌✅ (primary)	-	-	0

Bootstrap: 791.88s -> 787.871s (-0.51%)
Artifact size: 338.70 MiB -> 338.73 MiB (0.01%)