allowing target to say which regs are pseudo regs

[Doug Evans]

Would it make sense to allow a target to say which regs are pseudo regs?

i.e. make real_register() and pseudo_register() architecture-provided routines
[well, to be more precise, you'd just have one routine of course]

It seems rather clumsy to force a target to have registers
[0,NUM_REGS) be "real" regs and [NUM_REGS,NUM_REGS+NUM_PSEUDO_REGS)
be "pseudo" regs.  What's the difference other than
targets get to provide their own read/write routines for pseudo regs?

One would want to replace NUM_REGS and NUM_PSEUDO_REGS with
just NUM_REGS [or some such], and there'd be a set of corresponding
changes throughout the sources.