1 files changed, 1 insertions, 11 deletions
diff --git a/llvm/lib/CodeGen/DeadMachineInstructionElim.cpp b/llvm/lib/CodeGen/DeadMachineInstructionElim.cpp
index bbb4da83305..643efc2a4f9 100644
--- a/llvm/lib/CodeGen/DeadMachineInstructionElim.cpp
+++ b/llvm/lib/CodeGen/DeadMachineInstructionElim.cpp
@@ -127,17 +127,7 @@ bool DeadMachineInstructionElim::runOnMachineFunction(MachineFunction &MF) {
           unsigned Reg = MO.getReg();
           if (!TargetRegisterInfo::isVirtualRegister(Reg))
             continue;
-          MachineRegisterInfo::use_iterator nextI;
-          for (MachineRegisterInfo::use_iterator I = MRI->use_begin(Reg),
-               E = MRI->use_end(); I!=E; I=nextI) {
-            nextI = std::next(I);  // I is invalidated by the setReg
-            MachineOperand& Use = I.getOperand();
-            MachineInstr *UseMI = Use.getParent();
-            if (UseMI==MI)
-              continue;
-            assert(Use.isDebug());
-            UseMI->getOperand(0).setReg(0U);
-          }
+          MRI->markUsesInDebugValueAsUndef(Reg);
         }
         AnyChanges = true;
         MI->eraseFromParent();