Cache and use more ModId

[camsteffen]

Simplifying code a bit. Perhaps a tiny perf win from less parent module lookups.

[rustbot]

HIR ty lowering was modified

cc @fmease

[rustbot]

r? @mu001999

rustbot has assigned @mu001999.
They will have a look at your PR within the next two weeks and either review your PR or reassign to another reviewer.

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The reviewer was selected based on:

• Owners of files modified in this PR: compiler
• compiler expanded to 74 candidates
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[mu001999]

@bors try @rust-timer queue

[rust-bors]

☀️ Try build successful (CI)
Build commit: d23ae58 (d23ae583eaadc5bb12614b8b6dc9e36776122523)
Base parent: 76c35a1 (76c35a14a45897a366c11657ecbbe9ec4153ad17)

[rust-timer]

Finished benchmarking commit (d23ae58): comparison URL.

Overall result: ❌ regressions - please read:

Benchmarking means the PR may be perf-sensitive. It's automatically marked not fit for rolling up. Overriding is possible but disadvised: it risks changing compiler perf.

Next, please: If you can, justify the regressions found in this try perf run in writing along with @rustbot label: +perf-regression-triaged. If not, fix the regressions and do another perf run. Neutral or positive results will clear the label automatically.

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

Instruction count

Our most reliable metric. Used to determine the overall result above. However, even this metric can be noisy.

	mean	range	count
Regressions ❌ (primary)	0.2%	[0.2%, 0.3%]	12
Regressions ❌ (secondary)	0.3%	[0.1%, 0.5%]	18
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.2%	[0.2%, 0.3%]	12

Max RSS (memory usage)

Results (secondary -0.7%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	2.7%	[2.7%, 2.7%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-2.4%	[-2.6%, -2.2%]	2
All ❌✅ (primary)	-	-	0

Cycles

This perf run didn't have relevant results for this metric.

Binary size

This perf run didn't have relevant results for this metric.

Bootstrap: 488.274s -> 486.771s (-0.31%)
Artifact size: 387.66 MiB -> 387.61 MiB (-0.01%)

[mu001999]

Seems this instead leads to a slight perf regression. Do you have any ideas?

@rustbot author

[rustbot]

Reminder, once the PR becomes ready for a review, use @rustbot ready.

[rust-bors]

☔ The latest upstream changes (presumably #160506) made this pull request unmergeable. Please resolve the merge conflicts by rebasing.