Fix for PR4121. If TwoAddressInstructionPass removes a dead def, and the regB

operand was killed, the kill needs to be removed from regB's VarInfo.

llvm-svn: 71635

lib/CodeGen/TwoAddressInstructionPass.cpp

@@ -858,6 +858,12 @@ bool TwoAddressInstructionPass::runOnMachineFunction(MachineFunction &MF) {
                     }
                   }
                 }
+
+                // We're really going to nuke the old inst. If regB was marked
+                // as a kill we need to update its Kills list.
+                if (mi->getOperand(si).isKill())
+                  LV->removeVirtualRegisterKilled(regB, mi);
+
                 mbbi->erase(mi); // Nuke the old inst.
                 mi = nmi;
                 ++NumDeletes;