[Perf] Linux/x64: 1 Regression on 8/16/2026 12:17:32 AM +00:00

### Run Information

Name | Value
-- | --
Architecture | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [6276bd4a23e9e21597ccccba91f908917bc8e189](https://github.com/dotnet/runtime/commit/6276bd4a23e9e21597ccccba91f908917bc8e189)
Compare | [86f11fbddc7d604daa7296cd9cc8e82211c55c61](https://github.com/dotnet/runtime/commit/86f11fbddc7d604daa7296cd9cc8e82211c55c61)
Diff | [Diff](https://github.com/dotnet/runtime/compare/6276bd4a23e9e21597ccccba91f908917bc8e189...86f11fbddc7d604daa7296cd9cc8e82211c55c61)
Configs | AOT:true, CompilationMode:wasm, RunKind:micro

### Regressions in System.Collections.CreateAddAndClear<String>

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

• [Span - 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.Collections.CreateAddAndClear*'
```

### System.Collections.CreateAddAndClear<String>.Span(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 benchmark source in performance/src/benchmarks/micro/libraries/System.Collections/CreateAddAndClear.cs and the baseline/compare commit diff. Run the documented benchmarks_ci.py command with the System.Collections.CreateAddAndClear filter, then use the linked test report and profiling workflow to investigate the wasm AOT regression. Done means identifying and addressing the cause of the increase from 799.15 ns to 899.96 ns.

Written by the indexing model from the issue text.