diff --git a/llvm/lib/Transforms/Vectorize/VPlan.cpp b/llvm/lib/Transforms/Vectorize/VPlan.cpp
--- a/llvm/lib/Transforms/Vectorize/VPlan.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlan.cpp
@@ -1225,26 +1225,6 @@
   Slots[V] = NextSlot++;
 }
 
-void VPSlotTracker::assignSlots(const VPBlockBase *VPBB) {
-  if (auto *Region = dyn_cast<VPRegionBlock>(VPBB))
-    assignSlots(Region);
-  else
-    assignSlots(cast<VPBasicBlock>(VPBB));
-}
-
-void VPSlotTracker::assignSlots(const VPRegionBlock *Region) {
-  ReversePostOrderTraversal<const VPBlockBase *> RPOT(Region->getEntry());
-  for (const VPBlockBase *Block : RPOT)
-    assignSlots(Block);
-}
-
-void VPSlotTracker::assignSlots(const VPBasicBlock *VPBB) {
-  for (const VPRecipeBase &Recipe : *VPBB) {
-    for (VPValue *Def : Recipe.definedValues())
-      assignSlot(Def);
-  }
-}
-
 void VPSlotTracker::assignSlots(const VPlan &Plan) {
 
   for (const VPValue *V : Plan.VPExternalDefs)
@@ -1253,7 +1233,17 @@
   if (Plan.BackedgeTakenCount)
     assignSlot(Plan.BackedgeTakenCount);
 
-  ReversePostOrderTraversal<const VPBlockBase *> RPOT(Plan.getEntry());
-  for (const VPBlockBase *Block : RPOT)
-    assignSlots(Block);
+  ReversePostOrderTraversal<
+      VPBlockRecursiveTraversalWrapper<const VPBlockBase *>>
+      RPOT(VPBlockRecursiveTraversalWrapper<const VPBlockBase *>(
+          Plan.getEntry()));
+  for (const VPBlockBase *Block : RPOT) {
+    auto *VPBB = dyn_cast<VPBasicBlock>(Block);
+    if (!VPBB)
+      continue;
+    for (const VPRecipeBase &Recipe : *VPBB) {
+      for (VPValue *Def : Recipe.definedValues())
+        assignSlot(Def);
+    }
+  }
 }
diff --git a/llvm/lib/Transforms/Vectorize/VPlanValue.h b/llvm/lib/Transforms/Vectorize/VPlanValue.h
--- a/llvm/lib/Transforms/Vectorize/VPlanValue.h
+++ b/llvm/lib/Transforms/Vectorize/VPlanValue.h
@@ -372,11 +372,7 @@
   DenseMap<const VPValue *, unsigned> Slots;
   unsigned NextSlot = 0;
 
-  void assignSlots(const VPBlockBase *VPBB);
-  void assignSlots(const VPRegionBlock *Region);
-  void assignSlots(const VPBasicBlock *VPBB);
   void assignSlot(const VPValue *V);
-
   void assignSlots(const VPlan &Plan);
 
 public:
diff --git a/llvm/unittests/Transforms/Vectorize/VPlanTest.cpp b/llvm/unittests/Transforms/Vectorize/VPlanTest.cpp
--- a/llvm/unittests/Transforms/Vectorize/VPlanTest.cpp
+++ b/llvm/unittests/Transforms/Vectorize/VPlanTest.cpp
@@ -419,6 +419,21 @@
     EXPECT_EQ(R1BB1, FromIterator[6]);
     EXPECT_EQ(R1, FromIterator[7]);
 
+    ReversePostOrderTraversal<VPBlockRecursiveTraversalWrapper<VPBlockBase *>>
+        RPOT(Start);
+    FromIterator.clear();
+    for (VPBlockBase *VPBB : RPOT)
+      FromIterator.push_back(VPBB);
+    EXPECT_EQ(8u, FromIterator.size());
+    EXPECT_EQ(R1, FromIterator[0]);
+    EXPECT_EQ(R1BB1, FromIterator[1]);
+    EXPECT_EQ(R1BB3, FromIterator[2]);
+    EXPECT_EQ(R1BB2, FromIterator[3]);
+    EXPECT_EQ(R1BB4, FromIterator[4]);
+    EXPECT_EQ(R2, FromIterator[5]);
+    EXPECT_EQ(R2BB1, FromIterator[6]);
+    EXPECT_EQ(R2BB2, FromIterator[7]);
+
     // Use Plan to properly clean up created blocks.
     VPlan Plan;
     Plan.setEntry(R1);
@@ -479,6 +494,23 @@
     EXPECT_EQ(VPBB2, FromIterator[7]);
     EXPECT_EQ(R1BB2, FromIterator[8]);
 
+    VPBlockRecursiveTraversalWrapper<VPBlockBase *> Start(VPBB1);
+    ReversePostOrderTraversal<VPBlockRecursiveTraversalWrapper<VPBlockBase *>>
+        RPOT(Start);
+    FromIterator.clear();
+    for (VPBlockBase *VPBB : RPOT)
+      FromIterator.push_back(VPBB);
+    EXPECT_EQ(9u, FromIterator.size());
+    EXPECT_EQ(VPBB1, FromIterator[0]);
+    EXPECT_EQ(R1, FromIterator[1]);
+    EXPECT_EQ(R1BB1, FromIterator[2]);
+    EXPECT_EQ(R1BB2, FromIterator[3]);
+    EXPECT_EQ(R2, FromIterator[4]);
+    EXPECT_EQ(R2BB1, FromIterator[5]);
+    EXPECT_EQ(R2BB2, FromIterator[6]);
+    EXPECT_EQ(R1BB3, FromIterator[7]);
+    EXPECT_EQ(VPBB2, FromIterator[8]);
+
     // Use Plan to properly clean up created blocks.
     VPlan Plan;
     Plan.setEntry(VPBB1);