DescriptionQuantum computing is on the cusp of a revolution as prototypes with 100 quantum bits will soon appear and larger machines are on the horizon. The challenge will be to develop vertically-integrated systems in which programming languages, compilers, and runtime systems effectively map quantum algorithms to physical machines. In particular, I will discuss the opportunities and challenges for irregular applications on quantum machines. Quantum machines face challenges of communication and control which will be affected by irregularity. Physical connectivity faces scaling challenges and hierarchical structures may be needed. Yet, underneath these similarities with classical machines, quantum computers involve non-local interactions that make them uniquely different.