[Perf] Windows/x86: 2 Regressions on 7/15/2026 11:45:31 PM +00:00

### Run Information

Name | Value
-- | --
Architecture | x86
OS | Windows 10.0.22631
Queue | ViperWindows
Baseline | [051c1fd3c13fea8c1e60b68d9c7f63c3173e5593](https://github.com/dotnet/runtime/commit/051c1fd3c13fea8c1e60b68d9c7f63c3173e5593)
Compare | [1594ad1e1b5313c3ece119ced82b0a7ed2be7fbb](https://github.com/dotnet/runtime/commit/1594ad1e1b5313c3ece119ced82b0a7ed2be7fbb)
Diff | [Diff](https://github.com/dotnet/runtime/compare/051c1fd3c13fea8c1e60b68d9c7f63c3173e5593...1594ad1e1b5313c3ece119ced82b0a7ed2be7fbb)
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]()

| 1.17 μs | 1.29 μs | 1.10 | 0.00 | False | | |
|

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

| 1.06 μs | 1.12 μs | 1.06 | 0.01 | False | | |

![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

### System.Numerics.Tests.Perf_BigInteger.ToStringD(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 referenced benchmark source, dotnet/performance/src/benchmarks/micro/libraries/System.Runtime.Numerics/Perf.BigInteger.cs, and run the provided benchmarks_ci.py command for Perf_BigInteger. Compare the x86 Windows results with the linked baseline and test commits; done means identifying and addressing the cause of the Parse and ToStringD regressions.

Written by the indexing model from the issue text.