- MachineInstr *MI = BuildMI(*MF, Node->getDebugLoc(), II);
-
- // The MachineInstr constructor adds implicit-def operands. Scan through
- // these to determine which are dead.
- if (MI->getNumOperands() != 0 &&
- Node->getValueType(Node->getNumValues()-1) == MVT::Glue) {
- // First, collect all used registers.
- SmallVector<unsigned, 8> UsedRegs;
- for (SDNode *F = Node->getFlaggedUser(); F; F = F->getFlaggedUser())
- if (F->getOpcode() == ISD::CopyFromReg)
- UsedRegs.push_back(cast<RegisterSDNode>(F->getOperand(1))->getReg());
- else {
- // Collect declared implicit uses.
- const TargetInstrDesc &TID = TII->get(F->getMachineOpcode());
- UsedRegs.append(TID.getImplicitUses(),
- TID.getImplicitUses() + TID.getNumImplicitUses());
- // In addition to declared implicit uses, we must also check for
- // direct RegisterSDNode operands.
- for (unsigned i = 0, e = F->getNumOperands(); i != e; ++i)
- if (RegisterSDNode *R = dyn_cast<RegisterSDNode>(F->getOperand(i))) {
- unsigned Reg = R->getReg();
- if (Reg != 0 && TargetRegisterInfo::isPhysicalRegister(Reg))
- UsedRegs.push_back(Reg);
- }
- }
- // Then mark unused registers as dead.
- MI->setPhysRegsDeadExcept(UsedRegs, *TRI);
- }
-