[Perf] Linux/x64: 1 Regression on 9/6/2026 6:55:28 PM +00:00

### Run Information

Name | Value
-- | --
Architecture | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [134de00ac5934568c582a35322ae16a228db430d](https://github.com/dotnet/runtime/commit/134de00ac5934568c582a35322ae16a228db430d)
Compare | [570fcdab16c5b674bb59007f4faa705671d69cc2](https://github.com/dotnet/runtime/commit/570fcdab16c5b674bb59007f4faa705671d69cc2)
Diff | [Diff](https://github.com/dotnet/runtime/compare/134de00ac5934568c582a35322ae16a228db430d...570fcdab16c5b674bb59007f4faa705671d69cc2)
Configs | CompilationMode:wasm, RunKind:micro

### Regressions in System.Numerics.Tests.Constructor

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

• [ConstructorBenchmark_UInt16 - 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
python3 .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Numerics.Tests.Constructor*'
```

### System.Numerics.Tests.Constructor.ConstructorBenchmark_UInt16

#### 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 linked GenericVectorFromSpanConstructorTests.cs benchmark and compare the listed baseline and compare commits. Run the provided benchmarks_ci.py command for System.Numerics.Tests.Constructor and inspect the linked regression report and graph. Done means identifying and correcting the source of the ConstructorBenchmark_UInt16 regression, with the benchmark no longer showing the reported slowdown.

Vom Indexierungsmodell aus dem Issue-Text verfasst.