[Perf] Windows/x86: 1 Regression on 8/14/2026 4:30:00 PM +00:00

### Run Information

Name | Value
-- | --
Architecture | x86
OS | Windows 10.0.22631
Queue | ViperWindows
Baseline | [691fd960eb500743b4be71373b11b2263bdbc318](https://github.com/dotnet/runtime/commit/691fd960eb500743b4be71373b11b2263bdbc318)
Compare | [6276bd4a23e9e21597ccccba91f908917bc8e189](https://github.com/dotnet/runtime/commit/6276bd4a23e9e21597ccccba91f908917bc8e189)
Diff | [Diff](https://github.com/dotnet/runtime/compare/691fd960eb500743b4be71373b11b2263bdbc318...6276bd4a23e9e21597ccccba91f908917bc8e189)
Configs | CompilationMode:tiered, RunKind:micro

### Regressions in System.Numerics.Tests.Perf_BigInteger

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

• [Parse - 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.Numerics.Tests.Perf_BigInteger*'
```

### System.Numerics.Tests.Perf_BigInteger.Parse(numberString: 12345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890)

#### 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.Numerics/Perf.BigInteger.cs and run the provided benchmarks_ci.py command with the System.Numerics.Tests.Perf_BigInteger filter. Review the linked commit diff and test report for the Parse benchmark; done means the x86 Windows regression is explained and the benchmark no longer shows the reported slowdown.

Written by the indexing model from the issue text.