Only cache typeck results if it's the typeck root

[compiler-errors]

context: https://rust-lang.zulipchat.com/#narrow/stream/241847-t-compiler.2Fwg-incr-comp/topic/incr_comp_query_cache_promotion.20taking.20forever

Basically, typeck children just copy the typeck results of their typeck root item, so caching their results means copying the same typeck results for each child item.

r? @ghost

[compiler-errors]

@bors try @rust-timer queue

[bors]

⌛ Trying commit 938e807 with merge 0a3b79d20cb328b650c2c0a95cd1227e540734ff...

[bors]

☀️ Try build successful - checks-actions
Build commit: 0a3b79d20cb328b650c2c0a95cd1227e540734ff (0a3b79d20cb328b650c2c0a95cd1227e540734ff)

[rust-timer]

Finished benchmarking commit (0a3b79d20cb328b650c2c0a95cd1227e540734ff): comparison URL.

Overall result: ✅ improvements - no 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.

@bors rollup=never
@rustbot label: -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.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-1.8%	[-7.9%, -0.4%]	62
Improvements ✅ (secondary)	-4.4%	[-11.6%, -1.0%]	13
All ❌✅ (primary)	-1.8%	[-7.9%, -0.4%]	62

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.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-3.7%	[-8.3%, -0.5%]	36
Improvements ✅ (secondary)	-4.9%	[-5.0%, -4.8%]	3
All ❌✅ (primary)	-3.7%	[-8.3%, -0.5%]	36

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.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-2.5%	[-5.6%, -1.2%]	15
Improvements ✅ (secondary)	-5.0%	[-8.4%, -2.6%]	7
All ❌✅ (primary)	-2.5%	[-5.6%, -1.2%]	15

[compiler-errors]

r? compiler

[cjgillot]

@bors r+

[bors]

📌 Commit 938e807 has been approved by cjgillot

It is now in the queue for this repository.

[bors]

⌛ Testing commit 938e807 with merge 4b87ed9...

[bjorn3]

It's not just performance that improves significantly because of this change, but there is also a significant reduction in memory usage. And the query cache size is reduced by as much as 50% in some cases like serde.

[bors]

☀️ Test successful - checks-actions
Approved by: cjgillot
Pushing 4b87ed9 to master...

[rust-timer]

Finished benchmarking commit (4b87ed9): 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)	-1.8%	[-7.9%, -0.4%]	62
Improvements ✅ (secondary)	-4.6%	[-11.5%, -1.0%]	12
All ❌✅ (primary)	-1.8%	[-7.9%, -0.4%]	62

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.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	2.3%	[2.3%, 2.3%]	1
Improvements ✅ (primary)	-3.6%	[-8.2%, -0.7%]	30
Improvements ✅ (secondary)	-4.5%	[-4.8%, -4.1%]	3
All ❌✅ (primary)	-3.6%	[-8.2%, -0.7%]	30

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.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	3.6%	[2.8%, 4.7%]	3
Improvements ✅ (primary)	-2.7%	[-6.4%, -1.0%]	18
Improvements ✅ (secondary)	-5.1%	[-8.7%, -2.1%]	6
All ❌✅ (primary)	-2.7%	[-6.4%, -1.0%]	18

Binary size

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

Bootstrap: 655.48s -> 656.925s (0.22%)