Reduce BitSet size used in Borrows dataflow analysis

[vlad20012]

It looks like it is not needed to multiply the number of borrows by 2. Bits greater than self.borrow_set.len() are never set in this bitset. This should decrease the memory usage by an epsilon.

[rustbot]

r? @cjgillot

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[Kobzol]

@bors try @rust-timer queue

(:wave: @vlad20012! :D )

[bors]

⌛ Trying commit 6989246 with merge 5ea3d7fdc513e2d1c07b0fe05cef5c2fe684447f...

[vlad20012]

I traced it up to a849da6 (#49836). The multiplication by 2 should have been removed in that commit.

Btw I don't expect any measurable performance/memory improvements since the BitSet should usually be small. It's rather just a cleanup.

[bors]

☀️ Try build successful - checks-actions
Build commit: 5ea3d7fdc513e2d1c07b0fe05cef5c2fe684447f (5ea3d7fdc513e2d1c07b0fe05cef5c2fe684447f)

[rust-timer]

Finished benchmarking commit (5ea3d7fdc513e2d1c07b0fe05cef5c2fe684447f): comparison URL.

Overall result: ❌ regressions - 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)	0.4%	[0.3%, 0.5%]	2
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

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)	2.8%	[2.8%, 2.8%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-2.9%	[-3.6%, -2.1%]	3
All ❌✅ (primary)	-	-	0

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)	-	-	0
Improvements ✅ (secondary)	-8.6%	[-9.2%, -8.2%]	6
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: 657.767s -> 658.566s (0.12%)

[cjgillot]

Thanks!
@bors r+

[bors]

📌 Commit 6989246 has been approved by cjgillot

It is now in the queue for this repository.

[bors]

🌲 The tree is currently closed for pull requests below priority 50. This pull request will be tested once the tree is reopened.

[bors]

⌛ Testing commit 6989246 with merge 192f3950f0dbfb69647978011f930673c8fcfdda...

[bors]

💔 Test failed - checks-actions

[rust-log-analyzer]

A job failed! Check out the build log: (web) (plain)

Click to see the possible cause of the failure (guessed by this bot)

[cjgillot]

@bors retry

[bors]

⌛ Testing commit 6989246 with merge 4a59ba4...

[bors]

☀️ Test successful - checks-actions
Approved by: cjgillot
Pushing 4a59ba4 to master...

[rust-timer]

Finished benchmarking commit (4a59ba4): comparison URL.

Overall result: no relevant changes - no action needed

@rustbot label: -perf-regression

Instruction count

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

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)	-1.6%	[-1.6%, -1.6%]	1
Improvements ✅ (secondary)	-2.7%	[-3.1%, -2.3%]	4
All ❌✅ (primary)	-1.6%	[-1.6%, -1.6%]	1

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)	3.2%	[1.7%, 4.0%]	5
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: 659.596s -> 659.191s (-0.06%)