Update LLVM used in x86 CI dist builds to 15.0.0

[Kobzol]

LLVM 15.0.0 has been released, so we can use it in CI builds. We need (at least) LLVM 15 for BOLT, and we regularly update to most recent stable versions. It would also be good to first see the perf. effect of upgrading by itself, to have a better baseline for BOLT.

r? @Mark-Simulacrum

[Kobzol]

@bors try @rust-timer queue

[rust-timer]

Awaiting bors try build completion.

@rustbot label: +S-waiting-on-perf

[bors]

⌛ Trying commit da464dc with merge 66f7e1efcc4555d522bc1413951e659ba3e5bceb...

[bors]

☀️ Try build successful - checks-actions
Build commit: 66f7e1efcc4555d522bc1413951e659ba3e5bceb (66f7e1efcc4555d522bc1413951e659ba3e5bceb)

[rust-timer]

Queued 66f7e1efcc4555d522bc1413951e659ba3e5bceb with parent 0568b0a, future comparison URL.

[rust-timer]

Finished benchmarking commit (66f7e1efcc4555d522bc1413951e659ba3e5bceb): 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-review -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.

	mean1	range	count2
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.6%	[-0.6%, -0.6%]	11
Improvements ✅ (secondary)	-1.5%	[-1.5%, -1.5%]	1
All ❌✅ (primary)	-0.6%	[-0.6%, -0.6%]	11

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.

	mean1	range	count2
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	2.1%	[2.1%, 2.1%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-4.9%	[-6.9%, -1.0%]	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.

	mean1	range	count2
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	5.3%	[5.3%, 5.3%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-3.0%	[-3.0%, -3.0%]	1
All ❌✅ (primary)	-	-	0

Footnotes

1. the arithmetic mean of the percent change ↩ ↩² ↩³

2. number of relevant changes ↩ ↩² ↩³

[Kobzol]

Good news. There are some improvements, but not too many, which means that the BOLT wins were real and not just because of the LLVM upgrade.

[Mark-Simulacrum]

@bors r+

[bors]

📌 Commit da464dc has been approved by Mark-Simulacrum

It is now in the queue for this repository.

[bors]

⌛ Testing commit da464dc with merge 98f3001...

[bors]

☀️ Test successful - checks-actions
Approved by: Mark-Simulacrum
Pushing 98f3001 to master...

[rust-timer]

Finished benchmarking commit (98f3001): comparison URL.

Overall result: ❌✅ regressions and improvements - ACTION NEEDED

Next Steps: If you can justify the regressions found in this perf run, please indicate this with @rustbot label: +perf-regression-triaged along with sufficient written justification. If you cannot justify the regressions please open an issue or create a new PR that fixes the regressions, add a comment linking to the newly created issue or PR, and then add the perf-regression-triaged label to this PR.

@rustbot label: +perf-regression
cc @rust-lang/wg-compiler-performance

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean1	range	count2
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	1.3%	[1.3%, 1.3%]	1
Improvements ✅ (primary)	-0.6%	[-0.8%, -0.5%]	12
Improvements ✅ (secondary)	-0.5%	[-0.6%, -0.3%]	4
All ❌✅ (primary)	-0.6%	[-0.8%, -0.5%]	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.

	mean1	range	count2
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	3.3%	[2.5%, 4.1%]	3
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-1.6%	[-2.3%, -0.9%]	7
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.

	mean1	range	count2
Regressions ❌ (primary)	2.3%	[2.3%, 2.3%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	2.3%	[2.3%, 2.3%]	1

Footnotes

1. the arithmetic mean of the percent change ↩ ↩² ↩³

2. number of relevant changes ↩ ↩² ↩³

[Kobzol]

The improvements outweigh the regressions, and we can't really do anything here anyway.

@rustbot label: +perf-regression-triaged