diff --git a/llvm/lib/VMCore/Dominators.cpp b/llvm/lib/VMCore/Dominators.cpp
index 71eb3460e6c9..9ed4c44fa5ea 100644
--- a/llvm/lib/VMCore/Dominators.cpp
+++ b/llvm/lib/VMCore/Dominators.cpp
@@ -285,6 +285,7 @@ void DominatorTreeBase::reset() {
   Nodes.clear();
   IDoms.clear();
   Roots.clear();
+  Vertex.clear();
   RootNode = 0;
 }