Hi,
I am convinced that what I am about to ask is not possible but I would like
someone to confirm this.
Can I define in an insn a register constraint that depends on another register
value?
So, for
(set (match_operand:SI 0 "register_operand" "r")
(match_operand:SI 1 "register_operand" "r"))
What I would like to represent is the fact that 0 and 1 are register pairs, so
op0 is even and op1 is op0 + 1.
I noticed that avr defines register pair constraints but only for specific
registers. If you have 64 registers that will give you 22 pairs. I could, of
course, create all of these by hand by defining 23 classes and define a single
constraint that matches these classes but I would like to know if there's
another way.
Cheers,
Paulo Matos
