Update stdarch

[ehuss]

5 commits in 815d55c..cfba59f
2021-11-08 00:58:47 +0000 to 2021-11-19 01:29:04 +0000

• Work-around buggy Intel chips erroneously reporting BMI1/BMI2 support (Work-around buggy Intel chips erroneously reporting BMI1/BMI2 support stdarch#1249)
• complete armv8 instructions (complete armv8 instructions stdarch#1256)
• Fix i8mm feature with bootstrap compiler. (Fix i8mm feature with bootstrap compiler. stdarch#1252)
• Fix unused link_name attribute. (Fix unused link_name attribute. stdarch#1251)
• Add remaining insturctions (Add remaining insturctions stdarch#1250)

[rust-highfive]

⚠️ Warning ⚠️

• These commits modify submodules.

[ehuss]

I mistakenly thought #90382 updated stdarch to the latest master, but it was behind by several commits that I need.

[Amanieu]

@bors r+ rollup=never

[bors]

📌 Commit 458ed5a has been approved by Amanieu

[bors]

⌛ Testing commit 458ed5a with merge 6d48ee9...

[bors]

☀️ Test successful - checks-actions
Approved by: Amanieu
Pushing 6d48ee9 to master...

[rust-timer]

Finished benchmarking commit (6d48ee9): comparison url.

Summary: This change led to very large relevant mixed results 🤷 in compiler performance.

• Very large improvement in instruction counts (up to -5.8% on incr-unchanged builds of inflate)
• Small regression in instruction counts (up to 0.3% on incr-patched: println builds of html5ever)

If you disagree with this performance assessment, please file an issue in rust-lang/rustc-perf.

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

[pnkfelix]

Visited for weekly performance triage.

The only benchmark that regressed is "html5ever debug" ("incr-patched: println" and "incr-unchanged"), and only by a relatively small amount. This seems acceptable to me, compared to the effort involved in figuring out how this change could be related to that effect.

@rustbot label: +perf-regression-triaged