Add a codegen test for slice::from_ptr_range

[scottmcm]

I noticed back in #95579 that this didn't optimize as well as it should.

It's better now, after #95837 changed the code in from_ptr_range and llvm/llvm-project#54824 was fixed in LLVM 15.

So here's a test to keep it generating the good version.

[rust-highfive]

r? @Mark-Simulacrum

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[Mark-Simulacrum]

@bors r+

[bors]

📌 Commit 3356902 has been approved by Mark-Simulacrum

It is now in the queue for this repository.

[bors]

⌛ Testing commit 3356902 with merge a29f341...

[bors]

☀️ Test successful - checks-actions
Approved by: Mark-Simulacrum
Pushing a29f341 to master...

[rust-timer]

Finished benchmarking commit (a29f341): comparison URL.

Overall result: no relevant changes - no action needed

@rustbot label: -perf-regression

Instruction count

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

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)	2.6%	[2.6%, 2.6%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-4.7%	[-6.2%, -3.1%]	2
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)	5.1%	[5.1%, 5.1%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-3.5%	[-4.1%, -2.3%]	3
All ❌✅ (primary)	5.1%	[5.1%, 5.1%]	1

Footnotes

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

2. number of relevant changes ↩ ↩²