[Perf] Windows/x86: 1 Regression on 4/21/2026 4:43:45 AM +00:00

### Run Information

Name | Value
-- | --
Architecture | x86
OS | Windows 10.0.22631
Queue | ViperWindows
Baseline | [976701907bacb8447df45a1dd1fc089ec12e838f](https://github.com/dotnet/runtime/commit/976701907bacb8447df45a1dd1fc089ec12e838f)
Compare | [6f2ad2d6d76430b0f7c5bddabb64d9957092453a](https://github.com/dotnet/runtime/commit/6f2ad2d6d76430b0f7c5bddabb64d9957092453a)
Diff | [Diff](https://github.com/dotnet/runtime/compare/976701907bacb8447df45a1dd1fc089ec12e838f...6f2ad2d6d76430b0f7c5bddabb64d9957092453a)
Configs | CompilationMode:tiered, RunKind:micro

### Regressions in System.Tests.Perf_UInt32

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

• [TryParseHex - 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_UInt32*'
```

### System.Tests.Perf_UInt32.TryParseHex(value: "FFFFFFFF")

#### 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.Runtime/Perf.UInt32.cs lines 55-57 and reproduce System.Tests.Perf_UInt32 with the provided benchmarks_ci.py command. Compare the baseline and regression commits and inspect the TryParseHex result on Windows x86; done means identifying and addressing the cause of the 25% regression and confirming the benchmark returns to baseline.

Written by the indexing model from the issue text.