The LPM instruction has three forms:
form | feature |
---|---|
LPM | hasLPM |
LPM Rd, Z | hasLPMX |
LPM Rd, Z+ | hasLPMX |
The second form is always selected in ISelDAGToDAG, even on devices
without FeatureLPMX. This patch emits "LPM + MOV" on devices with
only FeatureLPM.