Another consideration that's just as important is in terms of physical design. By dividing one large register file into two smaller ones with fewer ports you s

Another consideration that's just as important is in terms of physical design. By dividing one large register file into two smaller ones with fewer ports you should be able to substantially decrease the overall size and power usage of the register files. Probably the bypass network too. I've never worked on compiler design, does it really make it that much more difficult? I'd imagine that the compiler would have a clear idea of whether a value is a memory address or not and could simply put addresses in the address registers and data in the data registers but it's likely I'm missing something.