select Vec::from_iter impls in a const block to optimize compile times

[the8472]

Ignoring whitespace diffs should make this easier to review.

This relies on the trick from #122301
Split out from #120682

[rustbot]

r? @Amanieu

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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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[the8472]

@bors try @rust-timer queue

[bors]

⌛ Trying commit 3ff1e44 with merge 383cc68...

[bors]

☀️ Try build successful - checks-actions
Build commit: 383cc68 (383cc68dbab7c7b269e592fac8e1fe09c1375547)

[rust-timer]

Finished benchmarking commit (383cc68): 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)	-0.7%	[-1.5%, -0.2%]	12
Improvements ✅ (secondary)	-2.4%	[-2.4%, -2.4%]	1
All ❌✅ (primary)	-0.7%	[-1.5%, -0.2%]	12

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)	4.7%	[4.7%, 4.7%]	1
Regressions ❌ (secondary)	6.3%	[6.2%, 6.4%]	2
Improvements ✅ (primary)	-3.4%	[-6.0%, -0.1%]	4
Improvements ✅ (secondary)	-4.4%	[-7.1%, -3.0%]	3
All ❌✅ (primary)	-1.8%	[-6.0%, 4.7%]	5

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)	-1.6%	[-1.6%, -1.6%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-1.6%	[-1.6%, -1.6%]	1

Binary size

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)	0.1%	[0.1%, 0.1%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.7%	[-1.9%, -0.0%]	35
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-0.7%	[-1.9%, 0.1%]	36

Bootstrap: 669.176s -> 670.043s (0.13%)
Artifact size: 312.73 MiB -> 312.77 MiB (0.01%)

[the8472]

Weird that a few opt binary sizes improve. This should only remove trivially-dead code. Maybe it's due to CGUs.

[Amanieu]

@bors r+

[bors]

📌 Commit 3ff1e44 has been approved by Amanieu

It is now in the queue for this repository.

[bors]

⌛ Testing commit 3ff1e44 with merge 0ad927c...

[bors]

☀️ Test successful - checks-actions
Approved by: Amanieu
Pushing 0ad927c to master...

[rust-timer]

Finished benchmarking commit (0ad927c): 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)	-0.6%	[-1.5%, -0.3%]	10
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-0.6%	[-1.5%, -0.3%]	10

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)	5.3%	[5.2%, 5.5%]	2
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-4.3%	[-8.0%, -0.1%]	4
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-1.1%	[-8.0%, 5.5%]	6

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)	-1.0%	[-1.6%, -0.7%]	4
Improvements ✅ (secondary)	-3.0%	[-3.0%, -3.0%]	1
All ❌✅ (primary)	-1.0%	[-1.6%, -0.7%]	4

Binary size

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)	0.1%	[0.1%, 0.1%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.7%	[-1.8%, -0.0%]	30
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-0.7%	[-1.8%, 0.1%]	31

Bootstrap: 670.84s -> 668.681s (-0.32%)
Artifact size: 314.97 MiB -> 315.01 MiB (0.01%)