remove fresh inference vars

[lcnr]

also fixes a caching bug in candidate selection 😅 going to split this into multiple prs before merging

development notes: https://hackmd.io/c2QwAwNATzCwDXR19IlOZA

r? @ghost

[lcnr]

@bors try @rust-timer queue

[rust-timer]

Awaiting bors try build completion.

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

[bors]

⌛ Trying commit ccb9f3b with merge 4e1d145e605fffb77d1d452ba178c5af9025dfeb...

[bors]

☀️ Try build successful - checks-actions
Build commit: 4e1d145e605fffb77d1d452ba178c5af9025dfeb (4e1d145e605fffb77d1d452ba178c5af9025dfeb)

[rust-timer]

Queued 4e1d145e605fffb77d1d452ba178c5af9025dfeb with parent 9a963e3, future comparison URL.

[rust-timer]

Finished benchmarking commit (4e1d145e605fffb77d1d452ba178c5af9025dfeb): comparison URL.

Overall result: ❌ regressions - 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.

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

Instruction count

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

	mean1	range	count2
Regressions ❌ (primary)	0.7%	[0.3%, 5.6%]	30
Regressions ❌ (secondary)	2.2%	[0.3%, 6.4%]	52
Improvements ✅ (primary)	-0.6%	[-0.8%, -0.5%]	2
Improvements ✅ (secondary)	-0.6%	[-0.9%, -0.3%]	2
All ❌✅ (primary)	0.6%	[-0.8%, 5.6%]	32

Max RSS (memory usage)

Results

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.

	mean1	range	count2
Regressions ❌ (primary)	2.0%	[0.6%, 3.3%]	10
Regressions ❌ (secondary)	6.2%	[3.1%, 9.1%]	11
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	2.0%	[0.6%, 3.3%]	10

Cycles

Results

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.

	mean1	range	count2
Regressions ❌ (primary)	2.2%	[1.4%, 3.7%]	5
Regressions ❌ (secondary)	3.6%	[1.3%, 7.7%]	30
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-4.1%	[-4.1%, -4.1%]	1
All ❌✅ (primary)	2.2%	[1.4%, 3.7%]	5

Footnotes

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

2. number of relevant changes ↩ ↩² ↩³

[lcnr]

opened #102360 for the caching bug as I am still unsure about what's the approach we want to take here

[lcnr]

this is blocked on #102472 at which point it will probably make more sense to rewrite this.