Index: include/llvm/Analysis/PostDominators.h
===================================================================
--- include/llvm/Analysis/PostDominators.h
+++ include/llvm/Analysis/PostDominators.h
@@ -29,7 +29,8 @@
 class PostDominatorTree : public PostDomTreeBase<BasicBlock> {
 public:
   using Base = PostDomTreeBase<BasicBlock>;
-
+  PostDominatorTree() = default;
+  explicit PostDominatorTree(Function &F) { recalculate(F); }
   /// Handle invalidation explicitly.
   bool invalidate(Function &F, const PreservedAnalyses &PA,
                   FunctionAnalysisManager::Invalidator &);
Index: unittests/IR/DominatorTreeBatchUpdatesTest.cpp
===================================================================
--- unittests/IR/DominatorTreeBatchUpdatesTest.cpp
+++ unittests/IR/DominatorTreeBatchUpdatesTest.cpp
@@ -22,9 +22,7 @@
 const auto CFGInsert = CFGBuilder::ActionKind::Insert;
 const auto CFGDelete = CFGBuilder::ActionKind::Delete;
 
-struct PostDomTree : PostDomTreeBase<BasicBlock> {
-  PostDomTree(Function &F) { recalculate(F); }
-};
+using PostDomTree = PostDominatorTree;
 
 using DomUpdate = DominatorTree::UpdateType;
 static_assert(
Index: unittests/IR/DominatorTreeTest.cpp
===================================================================
--- unittests/IR/DominatorTreeTest.cpp
+++ unittests/IR/DominatorTreeTest.cpp
@@ -21,9 +21,7 @@
 
 using namespace llvm;
 
-struct PostDomTree : PostDomTreeBase<BasicBlock> {
-  PostDomTree(Function &F) { recalculate(F); }
-};
+using PostDomTree = PostDominatorTree;
 
 /// Build the dominator tree for the function and run the Test.
 static void runWithDomTree(