[PERF] Revert "lub: don't bail out due to empty binders"

[lcnr]

Reverts #97867

cc #98359 (comment)

r? @rylev

[lcnr]

@bors try @rust-timer queue

[rust-timer]

Awaiting bors try build completion.

@rustbot label: +S-waiting-on-perf

[bors]

⌛ Trying commit a5c0525 with merge 9adffffc1583ad78c548317333e6079d155b8b9f...

[bors]

☀️ Try build successful - checks-actions
Build commit: 9adffffc1583ad78c548317333e6079d155b8b9f (9adffffc1583ad78c548317333e6079d155b8b9f)

[rust-timer]

Queued 9adffffc1583ad78c548317333e6079d155b8b9f with parent 116edb6, future comparison URL.

[rust-timer]

Finished benchmarking commit (9adffffc1583ad78c548317333e6079d155b8b9f): comparison url.

Instruction count

• Primary benchmarks: 😿 relevant regressions found
• Secondary benchmarks: 😿 relevant regressions found

	mean1	max	count2
Regressions 😿 (primary)	0.3%	0.3%	2
Regressions 😿 (secondary)	0.4%	0.7%	21
Improvements 🎉 (primary)	N/A	N/A	0
Improvements 🎉 (secondary)	N/A	N/A	0
All 😿🎉 (primary)	0.3%	0.3%	2

Max RSS (memory usage)

Results

• Primary benchmarks: no relevant changes found
• Secondary benchmarks: mixed results

	mean1	max	count2
Regressions 😿 (primary)	N/A	N/A	0
Regressions 😿 (secondary)	2.3%	2.3%	1
Improvements 🎉 (primary)	N/A	N/A	0
Improvements 🎉 (secondary)	-1.6%	-2.8%	3
All 😿🎉 (primary)	N/A	N/A	0

Cycles

Results

• Primary benchmarks: 😿 relevant regression found
• Secondary benchmarks: mixed results

	mean1	max	count2
Regressions 😿 (primary)	2.8%	2.8%	1
Regressions 😿 (secondary)	3.3%	3.3%	1
Improvements 🎉 (primary)	N/A	N/A	0
Improvements 🎉 (secondary)	-3.0%	-3.0%	1
All 😿🎉 (primary)	2.8%	2.8%	1

If you disagree with this performance assessment, please file an issue in rust-lang/rustc-perf.

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.

Next Steps: If you can justify the regressions found in this try perf run, please indicate this with @rustbot label: +perf-regression-triaged along with sufficient written justification. If you cannot justify the regressions please fix the regressions and do another perf run. If the next run shows neutral or positive results, the label will be automatically removed.

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

Footnotes

1. the arithmetic mean of the percent change ↩ ↩² ↩³

2. number of relevant changes ↩ ↩² ↩³

[lcnr]

alright, doesn't look like the culprit