diff --git a/lib/Transforms/Utils/PromoteMemoryToRegister.cpp b/lib/Transforms/Utils/PromoteMemoryToRegister.cpp
index 4b34b193773..54e1733c3f6 100644
--- a/lib/Transforms/Utils/PromoteMemoryToRegister.cpp
+++ b/lib/Transforms/Utils/PromoteMemoryToRegister.cpp
@@ -872,8 +872,10 @@ void PromoteMem2Reg::DetermineInsertionPoint(AllocaInst *AI, unsigned AllocaNum,
   }
 
   SmallVector<std::pair<unsigned, BasicBlock *>, 32> DFBlocks;
-  SmallPtrSet<DomTreeNode *, 32> Visited;
   SmallVector<DomTreeNode *, 32> Worklist;
+  SmallPtrSet<DomTreeNode *, 32> VisitedPQ;
+  SmallPtrSet<DomTreeNode *, 32> VisitedWorklist;
+
   while (!PQ.empty()) {
     DomTreeNodePair RootPair = PQ.top();
     PQ.pop();
@@ -887,6 +889,7 @@ void PromoteMem2Reg::DetermineInsertionPoint(AllocaInst *AI, unsigned AllocaNum,
 
     Worklist.clear();
     Worklist.push_back(Root);
+    VisitedWorklist.insert(Root);
 
     while (!Worklist.empty()) {
       DomTreeNode *Node = Worklist.pop_back_val();
@@ -905,7 +908,7 @@ void PromoteMem2Reg::DetermineInsertionPoint(AllocaInst *AI, unsigned AllocaNum,
         if (SuccLevel > RootLevel)
           continue;
 
-        if (!Visited.insert(SuccNode).second)
+        if (!VisitedPQ.insert(SuccNode).second)
           continue;
 
         BasicBlock *SuccBB = SuccNode->getBlock();
@@ -919,7 +922,7 @@ void PromoteMem2Reg::DetermineInsertionPoint(AllocaInst *AI, unsigned AllocaNum,
 
       for (DomTreeNode::iterator CI = Node->begin(), CE = Node->end(); CI != CE;
            ++CI) {
-        if (!Visited.count(*CI))
+        if (VisitedWorklist.insert(*CI).second)
           Worklist.push_back(*CI);
       }
     }