diff --git a/include/llvm/Analysis/PostDominators.h b/include/llvm/Analysis/PostDominators.h
index 381e65539c4..90de6bef42a 100644
--- a/include/llvm/Analysis/PostDominators.h
+++ b/include/llvm/Analysis/PostDominators.h
@@ -26,7 +26,8 @@ class raw_ostream;
 
 /// PostDominatorTree Class - Concrete subclass of DominatorTree that is used to
 /// compute the post-dominator tree.
-struct PostDominatorTree : public PostDomTreeBase<BasicBlock> {
+class PostDominatorTree : public PostDomTreeBase<BasicBlock> {
+public:
   using Base = PostDomTreeBase<BasicBlock>;
 
   /// Handle invalidation explicitly.
diff --git a/include/llvm/Analysis/RegionInfo.h b/include/llvm/Analysis/RegionInfo.h
index 71962235994..4bf64d191e5 100644
--- a/include/llvm/Analysis/RegionInfo.h
+++ b/include/llvm/Analysis/RegionInfo.h
@@ -62,7 +62,7 @@ class DominanceFrontier;
 class DominatorTree;
 class Loop;
 class LoopInfo;
-struct PostDominatorTree;
+class PostDominatorTree;
 class Region;
 template <class RegionTr> class RegionBase;
 class RegionInfo;
diff --git a/include/llvm/Support/GenericDomTree.h b/include/llvm/Support/GenericDomTree.h
index 7b3a1a554c5..84a935f1fb6 100644
--- a/include/llvm/Support/GenericDomTree.h
+++ b/include/llvm/Support/GenericDomTree.h
@@ -52,7 +52,7 @@ struct SemiNCAInfo;
 
 /// \brief Base class for the actual dominator tree node.
 template <class NodeT> class DomTreeNodeBase {
-  friend struct PostDominatorTree;
+  friend class PostDominatorTree;
   friend class DominatorTreeBase<NodeT, false>;
   friend class DominatorTreeBase<NodeT, true>;
   friend struct DomTreeBuilder::SemiNCAInfo<DominatorTreeBase<NodeT, false>>;