[Perf] Linux/x64: 2 Regressions on 12/4/2025 5:00:38 AM +00:00

### Run Information

Name | Value
-- | --
Architecture | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [b54c5d53ca8208e9bb5c95a2fbbd27f30df09b9d](https://github.com/dotnet/runtime/commit/b54c5d53ca8208e9bb5c95a2fbbd27f30df09b9d)
Compare | [32a02c7039aed473abc499c59916adccc2e1acde](https://github.com/dotnet/runtime/commit/32a02c7039aed473abc499c59916adccc2e1acde)
Diff | [Diff](https://github.com/dotnet/runtime/compare/b54c5d53ca8208e9bb5c95a2fbbd27f30df09b9d...32a02c7039aed473abc499c59916adccc2e1acde)
Configs | AOT:true, CompilationMode:wasm, RunKind:micro

### Regressions in System.Tests.Perf_Char

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

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

| 8.18 ns | 17.30 ns | 2.11 | 0.37 | False | | |
|

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

| 8.90 ns | 17.31 ns | 1.94 | 0.40 | 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 'System.Tests.Perf_Char*'
```

### System.Tests.Perf_Char.Char_ToLower(c: 'A', cultureName: en-US)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Tests.Perf_Char.Char_ToLower(c: 'a', cultureName: en-US)

#### 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)