Index: include/llvm/CodeGen/SlotIndexes.h
===================================================================
--- include/llvm/CodeGen/SlotIndexes.h
+++ include/llvm/CodeGen/SlotIndexes.h
@@ -414,7 +414,12 @@
     SlotIndex getInstructionIndex(const MachineInstr &MI) const {
       // Instructions inside a bundle have the same number as the bundle itself.
       const MachineInstr &BundleStart = *getBundleStart(MI.getIterator());
-      Mi2IndexMap::const_iterator itr = mi2iMap.find(&BundleStart);
+      // Skip debug instructions.
+      const MachineInstr &BundleNonDebug = *skipDebugInstructionsForward(
+                                  BundleStart.getIterator(), MI.getIterator());
+      assert(!BundleNonDebug.isDebugInstr() &&
+             "There is no non-debug instruction in the bundle.");
+      Mi2IndexMap::const_iterator itr = mi2iMap.find(&BundleNonDebug);
       assert(itr != mi2iMap.end() && "Instruction not found in maps.");
       return itr->second;
     }
Index: lib/CodeGen/LiveDebugVariables.cpp
===================================================================
--- lib/CodeGen/LiveDebugVariables.cpp
+++ lib/CodeGen/LiveDebugVariables.cpp
@@ -583,10 +583,16 @@
         continue;
       }
       // DBG_VALUE has no slot index, use the previous instruction instead.
-      SlotIndex Idx =
-          MBBI == MBB->begin()
-              ? LIS->getMBBStartIdx(MBB)
-              : LIS->getInstructionIndex(*std::prev(MBBI)).getRegSlot();
+      SlotIndex Idx;
+      if (MBBI == MBB->begin()) {
+	Idx = LIS->getMBBStartIdx(MBB);
+      } else {
+	const MachineInstr &PrevMI = *std::prev(MBBI);
+	if (PrevMI.isDebugInstr())
+	  Idx = LIS->getMBBStartIdx(MBB);
+	else
+	  Idx = LIS->getInstructionIndex(PrevMI).getRegSlot();
+      }
       // Handle consecutive DBG_VALUE instructions with the same slot index.
       do {
         if (handleDebugValue(*MBBI, Idx)) {