[Perf] Windows/x86: 1 Improvement on 9/14/2026 6:37:21 AM +00:00

### Run Information

Name | Value
-- | --
Architecture | x86
OS | Windows 10.0.22631
Queue | ViperWindows
Baseline | [edd70ca597f37a95a3ccc04c127fb8e883cc4139](https://github.com/dotnet/runtime/commit/edd70ca597f37a95a3ccc04c127fb8e883cc4139)
Compare | [a652cdfed564e5b96265a52d8d9d9d001efaeb7e](https://github.com/dotnet/runtime/commit/a652cdfed564e5b96265a52d8d9d9d001efaeb7e)
Diff | [Diff](https://github.com/dotnet/runtime/compare/edd70ca597f37a95a3ccc04c127fb8e883cc4139...a652cdfed564e5b96265a52d8d9d9d001efaeb7e)
Configs | CompilationMode:tiered, RunKind:micro

### Improvements in System.Collections.Tests.Perf_BitArray

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

• [BitArrayOr - 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.Collections.Tests.Perf_BitArray*'
```

### System.Collections.Tests.Perf_BitArray.BitArrayOr(Size: 512)

#### 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 benchmark source, src/benchmarks/micro/libraries/System.Collections/Perf.BitArray.cs lines 102-103, and run the provided benchmarks_ci.py command for Perf_BitArray. Compare the BitArrayOr result with the linked baseline and comparison reports; the payload does not define a code change or acceptance criteria beyond investigating the reported performance improvement.

Written by the indexing model from the issue text.