Paper detail

Towards Supporting QIR: Steps for Adopting the Quantum Intermediate Representation

Intermediate representations (IRs) play a crucial role in the software stack of a quantum computer to facilitate efficient optimizations for executing an application on hardware. One of those IRs is the Quantum Intermediate Representation (QIR), which builds on the classical LLVM compiler infrastructure. In this article, we outline different approaches to how QIR can be adopted. This exploration culminates in a demonstration of what it takes to turn an existing quantum circuit simulator into a QIR runtime and that such a transition is less daunting than it might seem at first. We further show that switching to QIR does not entail any performance deficits compared to the original simulator. On the contrary, the presented steps effortlessly allow adding support for arbitrary classical control flow to any classical simulator. We conclude with an outlook on future directions using QIR. The implemented QIR runtime is available under https://github.com/munich-quantum-toolkit/core.