> I'm curious. Have you tried out other approaches before you decided > to go with the virtual registers?
Yes. Getting GCC to understand the "unusual" addressing modes the RL78 uses was too much for the register allocator to handle. Even when the addressing modes are limited to "usual" ones, GCC doesn't have a good way to do regalloc and reload when there are limits on what registers you can use in an address expression, and it's worse when there are dependencies between operands, or limited numbers of address registers.
