Index: lib/CodeGen/SelectionDAG/SelectionDAG.cpp
===================================================================
--- lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -87,6 +87,15 @@
 void SelectionDAG::DAGUpdateListener::NodeDeleted(SDNode*, SDNode*) {}
 void SelectionDAG::DAGUpdateListener::NodeUpdated(SDNode*) {}
 
+#define DEBUG_TYPE "SelectionDAG"
+
+static void NewSDValueDbgMsg(SDValue V, StringRef Msg) {
+  DEBUG(
+    dbgs() << Msg;
+    V.dump();
+  );
+}
+
 //===----------------------------------------------------------------------===//
 //                              ConstantFPSDNode Class
 //===----------------------------------------------------------------------===//
@@ -1155,7 +1164,10 @@
     SmallVector<SDValue, 8> Ops;
     for (unsigned i = 0, e = VT.getVectorNumElements(); i != e; ++i)
       Ops.insert(Ops.end(), EltParts.begin(), EltParts.end());
-    return getNode(ISD::BITCAST, DL, VT, getBuildVector(ViaVecVT, DL, Ops));
+
+    SDValue V = getNode(ISD::BITCAST, DL, VT, getBuildVector(ViaVecVT, DL, Ops));
+    NewSDValueDbgMsg(V, "Creating constant: ");
+    return V;
   }
 
   assert(Elt->getBitWidth() == EltVT.getSizeInBits() &&
@@ -1180,6 +1192,8 @@
   SDValue Result(N, 0);
   if (VT.isVector())
     Result = getSplatBuildVector(VT, DL, Result);
+
+  NewSDValueDbgMsg(Result, "Creating constant: ");
   return Result;
 }
 
@@ -1208,9 +1222,13 @@
   ID.AddPointer(&V);
   void *IP = nullptr;
   SDNode *N = nullptr;
-  if ((N = FindNodeOrInsertPos(ID, DL, IP)))
-    if (!VT.isVector())
-      return SDValue(N, 0);
+  if ((N = FindNodeOrInsertPos(ID, DL, IP))) {
+    if (!VT.isVector()) {
+      SDValue V = SDValue(N, 0);
+      NewSDValueDbgMsg(V, "Creating fp constant: ");
+      return V;
+    }
+  }
 
   if (!N) {
     N = newSDNode<ConstantFPSDNode>(isTarget, &V, DL.getDebugLoc(), EltVT);
@@ -1221,6 +1239,7 @@
   SDValue Result(N, 0);
   if (VT.isVector())
     Result = getSplatBuildVector(VT, DL, Result);
+  NewSDValueDbgMsg(Result, "Creating fp constant: ");
   return Result;
 }
 
@@ -3453,7 +3472,9 @@
                ? DAG.getZExtOrTrunc(Op, DL, SVT)
                : DAG.getSExtOrTrunc(Op, DL, SVT);
 
-  return DAG.getBuildVector(VT, DL, Elts);
+  SDValue V = DAG.getBuildVector(VT, DL, Elts);
+  NewSDValueDbgMsg(V, "New node fold concat vectors: ");
+  return V;
 }
 
 /// Gets or creates the specified node.
@@ -3469,7 +3490,9 @@
   CSEMap.InsertNode(N, IP);
 
   InsertNode(N);
-  return SDValue(N, 0);
+  SDValue V = SDValue(N, 0);
+  NewSDValueDbgMsg(V, "Creating new node: ");
+  return V;
 }
 
 SDValue SelectionDAG::getNode(unsigned Opcode, const SDLoc &DL, EVT VT,
@@ -3830,7 +3853,9 @@
   }
 
   InsertNode(N);
-  return SDValue(N, 0);
+  SDValue V = SDValue(N, 0);
+  NewSDValueDbgMsg(V, "Creating new node: ");
+  return V;
 }
 
 static std::pair<APInt, bool> FoldValue(unsigned Opcode, const APInt &C1,
@@ -4103,7 +4128,9 @@
     ScalarResults.push_back(ScalarResult);
   }
 
-  return getBuildVector(VT, DL, ScalarResults);
+  SDValue V = getBuildVector(VT, DL, ScalarResults);
+  NewSDValueDbgMsg(V, "New node fold constant vector: ");
+  return V;
 }
 
 SDValue SelectionDAG::getNode(unsigned Opcode, const SDLoc &DL, EVT VT,
@@ -4603,7 +4630,9 @@
   }
 
   InsertNode(N);
-  return SDValue(N, 0);
+  SDValue V = SDValue(N, 0);
+  NewSDValueDbgMsg(V, "Creating new node: ");
+  return V;
 }
 
 SDValue SelectionDAG::getNode(unsigned Opcode, const SDLoc &DL, EVT VT,
@@ -4638,8 +4667,10 @@
       return V;
     // Vector constant folding.
     SDValue Ops[] = {N1, N2, N3};
-    if (SDValue V = FoldConstantVectorArithmetic(Opcode, DL, VT, Ops))
+    if (SDValue V = FoldConstantVectorArithmetic(Opcode, DL, VT, Ops)) {
+      NewSDValueDbgMsg(V, "New node vector constant folding: ");
       return V;
+    }
     break;
   }
   case ISD::SELECT:
@@ -4699,8 +4730,11 @@
     FoldingSetNodeID ID;
     AddNodeIDNode(ID, Opcode, VTs, Ops);
     void *IP = nullptr;
-    if (SDNode *E = FindNodeOrInsertPos(ID, DL, IP))
-      return SDValue(E, 0);
+    if (SDNode *E = FindNodeOrInsertPos(ID, DL, IP)) {
+      SDValue V = SDValue(E, 0);
+      NewSDValueDbgMsg(V, "Creating new node: ");
+      return V;
+    }
 
     N = newSDNode<SDNode>(Opcode, DL.getIROrder(), DL.getDebugLoc(), VTs);
     createOperands(N, Ops);
@@ -4711,7 +4745,9 @@
   }
 
   InsertNode(N);
-  return SDValue(N, 0);
+  SDValue V = SDValue(N, 0);
+  NewSDValueDbgMsg(V, "Creating new node: ");
+  return V;
 }
 
 SDValue SelectionDAG::getNode(unsigned Opcode, const SDLoc &DL, EVT VT,