[Perf] Windows/x64: 1 Improvement on 8/8/2026 9:56:52 PM +00:00

### Run Information

Name | Value
-- | --
Architecture | x64
OS | Windows 10.0.22631
Queue | ViperWindows
Baseline | [f5f5f83dd8676416636eda75d8c091c6c4f8d506](https://github.com/dotnet/runtime/commit/f5f5f83dd8676416636eda75d8c091c6c4f8d506)
Compare | [c668fd41fd95a3b52c783bfdc761604712010ba3](https://github.com/dotnet/runtime/commit/c668fd41fd95a3b52c783bfdc761604712010ba3)
Diff | [Diff](https://github.com/dotnet/runtime/compare/f5f5f83dd8676416636eda75d8c091c6c4f8d506...c668fd41fd95a3b52c783bfdc761604712010ba3)
Configs | CompilationMode:tiered, RunKind:micro

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

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

• [Fill - 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>.Fill(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 benchmark source at src/benchmarks/micro/libraries/System.Memory/Span.cs#L53-L54, then run the provided benchmarks_ci.py command filtered to System.Memory.Span.Fill. Compare the reported baseline and test results with the linked report; done requires determining and addressing the reported performance improvement.

Written by the indexing model from the issue text.