There are pros and cons to both approaches. I moved from stack to register because I was writing the code gen backend from scratch in any case and preferred to

There are pros and cons to both approaches. I moved from stack to register because I was writing the code gen backend from scratch in any case and preferred to have a register representation instead of converting from stack to register (which has to happen one way or another). Also mildly helpful with control flow analysis during bytecode generation and verification phases.