Add test for #98294

[nikic]

Add a test to make that the failure condition for this pattern is optimized away.

Fixes#98294.

[rust-highfive]

r? @Mark-Simulacrum

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[Mark-Simulacrum]

@bors r+ rollup=iffy

[bors]

📌 Commit 8a527ee has been approved by Mark-Simulacrum

It is now in the queue for this repository.

[matthiaskrgr]

@bors r- failed in a rollup
#101372 (comment)

[nikic]

Weird, this test does work fine in a local ./x.py test src/test/codegen run (also on x86_64, so there should be not platform difference).

I wasn't able to run x86_64-gnu locally due to #101438.

Anyone know what the relevant difference between x86_64 and a local run might be?

[Mark-Simulacrum]

Beyond sanitizers and profilers being enabled, we also use a downloaded LLVM rather than building from scratch. That should be up to date, but maybe we're missing some conditional? You could try enabling downloaded LLVM locally; that should work the same (and you can compare to CI log for the chosen hash).

[nikic]

It turns out the issue is debug assertion in std. I added an ignore-debug line, which is also used by many other codegen tests for vec/slice functionality.

[nikic]

@bors r=Mark-Simulacrum rollup=iffy

[bors]

📌 Commit cbf3b24 has been approved by Mark-Simulacrum

It is now in the queue for this repository.

[bors]

⌛ Testing commit cbf3b24 with merge 0568b0a...

[bors]

☀️ Test successful - checks-actions
Approved by: Mark-Simulacrum
Pushing 0568b0a to master...

[rust-timer]

Finished benchmarking commit (0568b0a): 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)	0.8%	[0.7%, 0.9%]	6
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-1.1%	[-1.1%, -1.1%]	1
All ❌✅ (primary)	0.8%	[0.7%, 0.9%]	6

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)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-2.4%	[-2.4%, -2.4%]	1
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)	3.4%	[3.4%, 3.4%]	1
Improvements ✅ (primary)	-3.0%	[-3.4%, -2.6%]	2
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-3.0%	[-3.4%, -2.6%]	2

Footnotes

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

2. number of relevant changes↩↩²↩³

[lqd]

this is noise, @rustbot label: +perf-regression-triaged