MLIR for Quantum Beyond Gate Cancellation: Quantum Circuit Mapping Reimagined
It provides an MLIR-native blueprint for computationally intensive quantum compilation tasks, benefiting quantum compiler developers seeking integration and performance improvements.
The paper reimplements a state-of-the-art quantum circuit mapping algorithm (A* search for qubit routing) within the MLIR compiler framework, achieving better solution quality and runtime than previous non-MLIR implementations.
The Multi-Level Intermediate Representation (MLIR) framework has become a cornerstone for building extensible, domain-specific compilers, with the quantum computing community already leveraging it to model quantum programs and implement basic optimizations. However, computationally intensive tasks in the quantum compilation pipeline, such as quantum circuit mapping, remain underexplored within the MLIR ecosystem. This paper proposes an MLIR-native blueprint for these non-local, quantum-specific optimization routines by reimplementing a well-established, state-of-the-art mapping A* search algorithm for qubit routing and SWAP insertion. Our evaluation demonstrates that this approach not only integrates seamlessly into an MLIR-based quantum compiler collection but also surpasses previous non-MLIR solutions in both solution quality and runtime. The implementation is open-source and publicly available at https://github.com/munich-quantum-toolkit/core.