[Perf] Windows/x64: 2 Regressions on 5/23/2026 8:24:06 PM +00:00

### Run Information

Name | Value
-- | --
Architecture | x64
OS | Windows 10.0.22631
Queue | ViperWindows
Baseline | [f2c9dc4cbcb05c580b08eed6b9eebe1998795a41](https://github.com/dotnet/runtime/commit/f2c9dc4cbcb05c580b08eed6b9eebe1998795a41)
Compare | [d198593b0563cd5364893144acddd454545df392](https://github.com/dotnet/runtime/commit/d198593b0563cd5364893144acddd454545df392)
Diff | [Diff](https://github.com/dotnet/runtime/compare/f2c9dc4cbcb05c580b08eed6b9eebe1998795a41...d198593b0563cd5364893144acddd454545df392)
Configs | CompilationMode:tiered, RunKind:micro

### Regressions in System.Tests.Perf_Array

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

• [ArrayAssign1D - Duration of single invocation]()
• 📝 - [Benchmark Source]()
• [ADX - Test Multi Config Graph]()

| 387.97 μs | 416.53 μs | 1.07 | 0.07 | False | | |
|

• [ArrayCreate2D - Duration of single invocation]()
• 📝 - [Benchmark Source]()
• [ADX - Test Multi Config Graph]()

| 388.12 ns | 413.05 ns | 1.06 | 0.02 | 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.Tests.Perf_Array*'
```

### System.Tests.Perf_Array.ArrayAssign1D

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Tests.Perf_Array.ArrayCreate2D

#### 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 src/benchmarks/micro/libraries/System.Runtime/Perf.Array.cs at lines 37-64 and the benchmarking workflow linked in the issue. Run the supplied System.Tests.Perf_Array filter on Windows/x64, then compare the baseline and test commits and review the linked benchmark reports. Done means the two regressions are reproduced, their cause is identified, and an appropriate change is validated.

Written by the indexing model from the issue text.