Fast path for processing some obligations in the new solver

[compiler-errors]

Inaugural perf test for new trait solver. We will see if it's actually affecting perf :>

r? lcnr

[compiler-errors]

@bors try @rust-timer queue

[bors]

⌛ Trying commit 9e31dcb with merge a08eb7a...

[bors]

☀️ Try build successful - checks-actions
Build commit: a08eb7a (a08eb7a687a8deb8493fbb5c836126164b7be581)

[rust-timer]

Finished benchmarking commit (a08eb7a): comparison URL.

Overall result: ❌✅ regressions and improvements - please read the text below

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-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)	0.7%	[0.5%, 1.1%]	8
Regressions ❌ (secondary)	0.8%	[0.6%, 1.2%]	5
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-1.0%	[-1.4%, -0.3%]	4
All ❌✅ (primary)	0.7%	[0.5%, 1.1%]	8

Max RSS (memory usage)

Results (primary 1.3%, secondary 1.4%)

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)	2.0%	[0.7%, 3.5%]	5
Regressions ❌ (secondary)	2.6%	[1.1%, 6.8%]	19
Improvements ✅ (primary)	-2.1%	[-2.1%, -2.1%]	1
Improvements ✅ (secondary)	-1.7%	[-4.3%, -0.4%]	8
All ❌✅ (primary)	1.3%	[-2.1%, 3.5%]	6

Cycles

Results (primary -2.5%, 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)	1.2%	[0.9%, 2.2%]	7
Improvements ✅ (primary)	-2.5%	[-2.5%, -2.5%]	1
Improvements ✅ (secondary)	-1.4%	[-2.5%, -0.4%]	6
All ❌✅ (primary)	-2.5%	[-2.5%, -2.5%]	1

Binary size

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

Bootstrap: 775.66s -> 775.985s (0.04%)
Artifact size: 365.38 MiB -> 365.32 MiB (-0.02%)

[compiler-errors]

Theory: Fast path caused things to be slower by unnecessarily considering the goal to have HasChanged::Yes. Region responses aren't considered to have changed inference state, so no need to rerun things.

@bors try @rust-timer queue

[bors]

⌛ Trying commit 702599b with merge 8250145...

[bors]

☀️ Try build successful - checks-actions
Build commit: 8250145 (8250145e631d19aca63574d7b9910628ade29c1f)

[rust-timer]

Finished benchmarking commit (8250145): comparison URL.

Overall result: ❌✅ regressions and improvements - please read the text below

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-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)	1.1%	[1.1%, 1.1%]	1
Regressions ❌ (secondary)	0.8%	[0.6%, 1.0%]	2
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.9%	[-1.6%, -0.5%]	12
All ❌✅ (primary)	1.1%	[1.1%, 1.1%]	1

Max RSS (memory usage)

Results (primary 3.1%, secondary -1.2%)

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)	8.1%	[7.5%, 8.8%]	2
Regressions ❌ (secondary)	3.2%	[0.8%, 5.7%]	2
Improvements ✅ (primary)	-7.1%	[-7.1%, -7.1%]	1
Improvements ✅ (secondary)	-3.4%	[-5.0%, -0.6%]	4
All ❌✅ (primary)	3.1%	[-7.1%, 8.8%]	3

Cycles

Results (secondary 0.3%)

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)	-	-	0
Regressions ❌ (secondary)	1.0%	[0.4%, 1.2%]	5
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.7%	[-0.8%, -0.6%]	3
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: 774.349s -> 775.576s (0.16%)
Artifact size: 365.45 MiB -> 365.31 MiB (-0.04%)

[compiler-errors]

Folding this into #141135.