[Perf] Windows/x86: 1 Regression on 8/4/2026 3:42:07 PM +00:00

### Run Information

Name | Value
-- | --
Architecture | x86
OS | Windows 10.0.22631
Queue | ViperWindows
Baseline | [80aa3f8c5a2d33664fbedafd2f2bb18fdeb8002f](https://github.com/dotnet/runtime/commit/80aa3f8c5a2d33664fbedafd2f2bb18fdeb8002f)
Compare | [f107b2325cccfd453f9bf46013159f4704ea56c2](https://github.com/dotnet/runtime/commit/f107b2325cccfd453f9bf46013159f4704ea56c2)
Diff | [Diff](https://github.com/dotnet/runtime/compare/80aa3f8c5a2d33664fbedafd2f2bb18fdeb8002f...f107b2325cccfd453f9bf46013159f4704ea56c2)
Configs | CompilationMode:tiered, RunKind:micro

### Regressions in System.Memory.Span<Int32>

Benchmark | Baseline | Test | Test/Base | Test Quality | Edge Detector | Baseline IR | Compare IR | IR Ratio
-- | -- | -- | -- | -- | -- | -- | -- | --
|

• [Reverse - Duration of single invocation]()
• 📝 - [Benchmark Source]()
• [ADX - Test Multi Config Graph]()

![graph]()
[Test Report]()

### Repro
General Docs link: https://github.com/dotnet/performance/blob/main/docs/benchmarking-workflow-dotnet-runtime.md

```cmd
git clone https://github.com/dotnet/performance.git
py .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Memory.Span*'
```

### System.Memory.Span<Int32>.Reverse(Size: 3000)

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

[Profiling workflow for dotnet/runtime repository](https://github.com/dotnet/performance/blob/master/docs/profiling-workflow-dotnet-runtime.md)
[Benchmarking workflow for dotnet/runtime repository](https://github.com/dotnet/performance/blob/master/docs/benchmarking-workflow-dotnet-runtime.md)

Start with the System.Memory.Span.Reverse benchmark in performance/src/benchmarks/micro/libraries/System.Memory/Span.cs and reproduce it with the provided benchmarks_ci.py command. Compare the baseline and test commits, then inspect the linked benchmark and JIT reports to identify the regression. Done means the cause is addressed and the benchmark no longer regresses on x86 Windows.

Written by the indexing model from the issue text.