One Forth I've seen, FreeForth, compiles subroutine threaded machine code rather than traditional direct/indirect threaded code, and it does register renaming a

One Forth I've seen, FreeForth, compiles subroutine threaded machine code rather than traditional direct/indirect threaded code, and it does register renaming at compile time to hide SWAPs, generating as necessary a real SWAP at the end. You do need a stack though, there are only so many registers. Even C has a stack - it just mixes up data and returns on the same one, which means it needs two extra allocation mechanisms (function return value and malloc) for data that must outlive the function's lexical extent.