Index: lib/CodeGen/LiveDebugVariables.cpp
===================================================================
--- lib/CodeGen/LiveDebugVariables.cpp
+++ lib/CodeGen/LiveDebugVariables.cpp
@@ -675,13 +675,6 @@
     // Don't track copies from physregs, it is too expensive.
     extendDef(Idx, LocNo, LR, VNI, nullptr, LIS, MDT, UVS);
   }
-
-  // Finally, erase all the undefs.
-  for (LocMap::iterator I = locInts.begin(); I.valid();)
-    if (I.value() == ~0u)
-      I.erase();
-    else
-      ++I;
 }
 
 void LDVImpl::computeIntervals() {
@@ -928,15 +921,18 @@
                                  LiveIntervals &LIS,
                                  const TargetInstrInfo &TII) {
   MachineBasicBlock::iterator I = findInsertLocation(MBB, Idx, LIS);
-  MachineOperand &Loc = locations[LocNo];
+  MachineOperand *Loc = LocNo == ~0u ? nullptr : &locations[LocNo];
   ++NumInsertedDebugValues;
 
-  if (Loc.isReg())
+  if (!Loc)
+    BuildMI(*MBB, I, findDebugLoc(), TII.get(TargetOpcode::DBG_VALUE),
+            IsIndirect, 0, offset, variable);
+  else if (Loc->isReg())
     BuildMI(*MBB, I, findDebugLoc(), TII.get(TargetOpcode::DBG_VALUE),
-            IsIndirect, Loc.getReg(), offset, variable);
+            IsIndirect, Loc->getReg(), offset, variable);
   else
     BuildMI(*MBB, I, findDebugLoc(), TII.get(TargetOpcode::DBG_VALUE))
-      .addOperand(Loc).addImm(offset).addMetadata(variable);
+      .addOperand(*Loc).addImm(offset).addMetadata(variable);
 }
 
 void UserValue::emitDebugValues(VirtRegMap *VRM, LiveIntervals &LIS,
Index: lib/Transforms/Scalar/SROA.cpp
===================================================================
--- lib/Transforms/Scalar/SROA.cpp
+++ lib/Transforms/Scalar/SROA.cpp
@@ -874,24 +874,9 @@
     for (SmallVectorImpl<DbgValueInst *>::const_iterator I = DVIs.begin(),
            E = DVIs.end(); I != E; ++I) {
       DbgValueInst *DVI = *I;
-      Value *Arg = nullptr;
-      if (StoreInst *SI = dyn_cast<StoreInst>(Inst)) {
-        // If an argument is zero extended then use argument directly. The ZExt
-        // may be zapped by an optimization pass in future.
-        if (ZExtInst *ZExt = dyn_cast<ZExtInst>(SI->getOperand(0)))
-          Arg = dyn_cast<Argument>(ZExt->getOperand(0));
-        else if (SExtInst *SExt = dyn_cast<SExtInst>(SI->getOperand(0)))
-          Arg = dyn_cast<Argument>(SExt->getOperand(0));
-        if (!Arg)
-          Arg = SI->getValueOperand();
-      } else if (LoadInst *LI = dyn_cast<LoadInst>(Inst)) {
-        Arg = LI->getPointerOperand();
-      } else {
-        continue;
-      }
-      Instruction *DbgVal =
-        DIB.insertDbgValueIntrinsic(Arg, 0, DIVariable(DVI->getVariable()),
-                                     Inst);
+      Value *Arg = UndefValue::get(DVI->getValue()->getType());
+      Instruction *DbgVal = DIB.insertDbgValueIntrinsic(
+          Arg, 0, DIVariable(DVI->getVariable()), Inst);
       DbgVal->setDebugLoc(DVI->getDebugLoc());
     }
   }