Implement wide load program memory pseudo instructions

[dylanmckay]

Currently no logic exists in AVRExpandPseudoInsts.cpp to lower the lpmw Rd, Z or lpmw Rd, Z+ instructions.

They are defined as pseudo instructions, but they are not lowered. Because of this, using them will cause an error in LLVM.

LLVM ERROR: Not supported instr: <MCInst 102 <MCOperand Reg:52> <MCOperandReg:52>>

[dylanmckay]

I believe we shouldn't even have wide program memory load instructions.

The instruction selector will never need it (lpm instructions will only be needed in hand-crafted assembly).

I will go ahead and remove the wide variants.

[agnat]

The instruction selector will never need it (lpm instructions will only be needed in hand-crafted assembly).

I'm not sure that is true. This code looks like it is trying to select a wide flash load.

That said I'm okay with removing it since I don't believe in wide pseudo instructions anyway... :P

[dylanmckay]

I'm not sure that is true. This code looks like it is trying to select a wide flash load.

I stand corrected.

That said I'm okay with removing it since I don't believe in wide pseudo instructions anyway... :P

I think we should hold off until we get the backend sorted out so we don't actually need them ;)