Index: include/llvm/CodeGen/SelectionDAG.h
===================================================================
--- include/llvm/CodeGen/SelectionDAG.h
+++ include/llvm/CodeGen/SelectionDAG.h
@@ -120,13 +120,7 @@
 public:
   SDDbgInfo() {}
 
-  void add(SDDbgValue *V, const SDNode *Node, bool isParameter) {
-    if (isParameter) {
-      ByvalParmDbgValues.push_back(V);
-    } else     DbgValues.push_back(V);
-    if (Node)
-      DbgValMap[Node].push_back(V);
-  }
+  void add(SDDbgValue *V, const SDNode *Node, bool isParameter);
 
   void clear() {
     DbgValMap.clear();
Index: lib/CodeGen/SelectionDAG/SDNodeDbgValue.h
===================================================================
--- lib/CodeGen/SelectionDAG/SDNodeDbgValue.h
+++ lib/CodeGen/SelectionDAG/SDNodeDbgValue.h
@@ -80,43 +80,63 @@
   }
 
   // Returns the kind.
-  DbgValueKind getKind() { return kind; }
+  DbgValueKind getKind() const { return kind; }
 
   // Returns the MDNode pointer.
-  MDNode *getMDPtr() { return mdPtr; }
+  MDNode *getMDPtr() const { return mdPtr; }
 
   // Returns the SDNode* for a register ref
-  SDNode *getSDNode() { assert (kind==SDNODE); return u.s.Node; }
+  SDNode *getSDNode() const { assert (kind==SDNODE); return u.s.Node; }
 
   // Returns the ResNo for a register ref
-  unsigned getResNo() { assert (kind==SDNODE); return u.s.ResNo; }
+  unsigned getResNo() const { assert (kind==SDNODE); return u.s.ResNo; }
 
   // Returns the Value* for a constant
-  const Value *getConst() { assert (kind==CONST); return u.Const; }
+  const Value *getConst() const { assert (kind==CONST); return u.Const; }
 
   // Returns the FrameIx for a stack object
-  unsigned getFrameIx() { assert (kind==FRAMEIX); return u.FrameIx; }
+  unsigned getFrameIx() const { assert (kind==FRAMEIX); return u.FrameIx; }
 
   // Returns whether this is an indirect value.
-  bool isIndirect() { return IsIndirect; }
+  bool isIndirect() const { return IsIndirect; }
 
   // Returns the offset.
-  uint64_t getOffset() { return Offset; }
+  uint64_t getOffset() const { return Offset; }
 
   // Returns the DebugLoc.
-  DebugLoc getDebugLoc() { return DL; }
+  DebugLoc getDebugLoc() const { return DL; }
 
   // Returns the SDNodeOrder.  This is the order of the preceding node in the
   // input.
-  unsigned getOrder() { return Order; }
+  unsigned getOrder() const { return Order; }
 
   // setIsInvalidated / isInvalidated - Setter / getter of the "Invalidated"
   // property. A SDDbgValue is invalid if the SDNode that produces the value is
   // deleted.
   void setIsInvalidated() { Invalid = true; }
-  bool isInvalidated() { return Invalid; }
+  bool isInvalidated() const { return Invalid; }
 };
 
+inline bool operator==(const SDDbgValue &a, const SDDbgValue &b) {
+  if (a.getKind() == b.getKind() &&
+      a.getMDPtr() == b.getMDPtr() &&
+      a.isIndirect() == b.isIndirect() &&
+      a.getOffset() == b.getOffset() &&
+      a.getDebugLoc() == b.getDebugLoc() &&
+      a.getOrder() == b.getOrder() &&
+      a.isInvalidated() == b.isInvalidated())
+    switch (a.getKind()) {
+    case SDDbgValue::SDNODE:
+      return a.getSDNode() == b.getSDNode() && a.getResNo() == b.getResNo();
+    case SDDbgValue::CONST:
+      return a.getConst() == b.getConst();
+    case SDDbgValue::FRAMEIX:
+      return a.getFrameIx() == b.getFrameIx();
+    }
+  return false;
+}
+
+  
 } // end llvm namespace
 
 #endif
Index: lib/CodeGen/SelectionDAG/SelectionDAG.cpp
===================================================================
--- lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -6169,6 +6169,18 @@
   return DAGSize;
 }
 
+void SDDbgInfo::add(SDDbgValue *V, const SDNode *Node, bool isParameter) {
+  if (isParameter) {
+    ByvalParmDbgValues.push_back(V);
+  } else     DbgValues.push_back(V);
+  if (Node) {
+    auto &Vals = DbgValMap[Node];
+    for (auto *Val : Vals)
+      if (*Val == *V) return;
+    Vals.push_back(V);
+  }
+}
+
 /// AddDbgValue - Add a dbg_value SDNode. If SD is non-null that means the
 /// value is produced by SD.
 void SelectionDAG::AddDbgValue(SDDbgValue *DB, SDNode *SD, bool isParameter) {