+
+ // Is the register live before? Otherwise we may have to add a read-undef
+ // flag for subregister defs.
+ if (MRI->tracksSubRegLiveness()) {
+ if ((I == LI.begin() || std::prev(I)->end < Def) && !VNI->isPHIDef()) {
+ MachineInstr *MI = getInstructionFromIndex(Def);
+ MI->addRegisterDefReadUndef(LI.reg);
+ }
+ }
+
+ if (I->end != Def.getDeadSlot())