- if (MI->isDebugValue()) {
- // Don't delete the DBG_VALUE itself, but if its Value operand is
- // a vreg and this is the only use, substitute an undef operand;
- // the former operand will then be deleted normally.
- if (MI->getNumOperands()==3 && MI->getOperand(0).isReg()) {
- unsigned Reg = MI->getOperand(0).getReg();
- MachineRegisterInfo::use_iterator I = MRI->use_begin(Reg);
- assert(I != MRI->use_end());
- if (++I == MRI->use_end())
- // only one use, which must be this DBG_VALUE.
- MI->getOperand(0).setReg(0U);
- }
- }
-