fb8dbd1fb6
7dc20ab introduced an extra COPY when spilling and filling a PNR register, which can't be elided as the input (PNR predicate) and output (PPR predicate) register classes differ. The patch adds a new register class that covers both PPR and PNR so that STR_PXI and LDR_PXI can take either of them, removing the need for the copy.