[Aardappel]

The multi-value proposal breaks the ability to turn Wasm into expressions easily, and thus makes it even more of a stack machine than it already is. Dup and swap may still be added in the future.

A defining feature of a register machine is that the actual instruction encoding has direct references to source and destination registers in it. Wasm doesn't have those, it has explicit get_local instructions instead.

That said, if you turn off LLVM's WebAssemblyRegStackify pass, all LLVM IR's values will end up in locals, with little to no stack usage. Still no register machine, but a bit more of a grey area :)