[Perf] Linux/x64: 2 Regressions on 6/20/2026 10:42:33 AM +00:00

### Run Information

Name | Value
-- | --
Architecture | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [8a395fa3d63a95b22b1e60dfeb3263668ef9b086](https://github.com/dotnet/runtime/commit/8a395fa3d63a95b22b1e60dfeb3263668ef9b086)
Compare | [b4ca93f1d026919b29a1000cf520db442cabf61b](https://github.com/dotnet/runtime/commit/b4ca93f1d026919b29a1000cf520db442cabf61b)
Diff | [Diff](https://github.com/dotnet/runtime/compare/8a395fa3d63a95b22b1e60dfeb3263668ef9b086...b4ca93f1d026919b29a1000cf520db442cabf61b)
Configs | AOT:true, CompilationMode:wasm, RunKind:micro

### Regressions in PerfLabTests.CastingPerf2.CastingPerf

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

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

| 431.75 μs | 490.67 μs | 1.14 | 0.06 | False | | |
|

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

| 145.13 μs | 157.38 μs | 1.08 | 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
python3 .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'PerfLabTests.CastingPerf2.CastingPerf*'
```

### PerfLabTests.CastingPerf2.CastingPerf.ScalarValueTypeObj

#### ETL Files

#### Histogram

#### JIT Disasms

### PerfLabTests.CastingPerf2.CastingPerf.IFooObjIsIFoo

#### 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/runtime/perflab/CastingPerf2.cs lines 148-154 and 203-208, then read the benchmarking workflow linked in the issue. Run the provided benchmarks_ci.py command and compare the baseline and test commits, using the regression report and graphs to investigate both casting benchmarks. Done means the regressions are explained and the issue is resolved or appropriately triaged.

Written by the indexing model from the issue text.