Worked on the CodeLinaro/onnxruntime repository to address a specific issue in ONNX Runtime graph optimization, focusing on VitisAI deployment scenarios. Using C++ and compiler development expertise, implemented a targeted bug fix in OrtShapeInferContext to handle optional inputs that lack a defined type. The solution introduced the use of an undefined data type and an empty shape as placeholders, ensuring correct context construction and more reliable shape inference. This approach improved the stability and maintainability of graph optimization pipelines, reducing the risk of inference errors and enhancing compatibility across different execution providers through consistent handling of optional input scenarios.