Fix handling of dead unwinds in backward analyses

[tmiasko]

Dead unwinds set contains a head of an unreachable unwind edge.

[rustbot]

r? @wesleywiser

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[wesleywiser]

@bors r+

[bors]

📌 Commit 357c3cf has been approved by wesleywiser

It is now in the queue for this repository.

[bors]

⌛ Testing commit 357c3cf with merge b7cdb63...

[bors]

☀️ Test successful - checks-actions
Approved by: wesleywiser
Pushing b7cdb63 to master...

[rust-timer]

Finished benchmarking commit (b7cdb63): comparison URL.

Overall result: ❌ regressions - 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)	0.7%	[0.7%, 0.7%]	1
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)	1.0%	[1.0%, 1.0%]	2
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Cycles

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