[Perf] Windows/x86: 1 Regression on 7/24/2026 12:29:24 AM +00:00

### Run Information

Name | Value
-- | --
Architecture | x86
OS | Windows 10.0.22631
Queue | ViperWindows
Baseline | [7ffec088158c895276b85cf176e37904f7d53a56](https://github.com/dotnet/runtime/commit/7ffec088158c895276b85cf176e37904f7d53a56)
Compare | [b96436e0baf6f641176187cd79a562ee68979d00](https://github.com/dotnet/runtime/commit/b96436e0baf6f641176187cd79a562ee68979d00)
Diff | [Diff](https://github.com/dotnet/runtime/compare/7ffec088158c895276b85cf176e37904f7d53a56...b96436e0baf6f641176187cd79a562ee68979d00)
Configs | CompilationMode:tiered, RunKind:micro

### Regressions in System.Tests.Perf_Enum

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

• [ToString_Format_NonFlags - 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.Tests.Perf_Enum*'
```

### System.Tests.Perf_Enum.ToString_Format_NonFlags(value: Friday, format: "X")

#### 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 src/benchmarks/micro/libraries/System.Runtime/Perf.Enum.cs#L57-L68 and compare the listed baseline and compare commits. Run the provided benchmarks_ci.py command for System.Tests.Perf_Enum*, then use the linked test report and history to confirm the ToString_Format_NonFlags regression. Done means the regression is explained and an appropriate fix or follow-up is identified.

Written by the indexing model from the issue text.