Update clang to r339409.

Change-Id: I800772d2d838223be1f6b40d490c4591b937fca2
diff --git a/linux-x64/clang/include/llvm/Analysis/PostDominators.h b/linux-x64/clang/include/llvm/Analysis/PostDominators.h
index 9a8c4d7..f2dc8d1 100644
--- a/linux-x64/clang/include/llvm/Analysis/PostDominators.h
+++ b/linux-x64/clang/include/llvm/Analysis/PostDominators.h
@@ -30,12 +30,14 @@
 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 &);
 };
 
-/// \brief Analysis pass which computes a \c PostDominatorTree.
+/// Analysis pass which computes a \c PostDominatorTree.
 class PostDominatorTreeAnalysis
     : public AnalysisInfoMixin<PostDominatorTreeAnalysis> {
   friend AnalysisInfoMixin<PostDominatorTreeAnalysis>;
@@ -43,15 +45,15 @@
   static AnalysisKey Key;
 
 public:
-  /// \brief Provide the result type for this analysis pass.
+  /// Provide the result type for this analysis pass.
   using Result = PostDominatorTree;
 
-  /// \brief Run the analysis pass over a function and produce a post dominator
+  /// Run the analysis pass over a function and produce a post dominator
   ///        tree.
   PostDominatorTree run(Function &F, FunctionAnalysisManager &);
 };
 
-/// \brief Printer pass for the \c PostDominatorTree.
+/// Printer pass for the \c PostDominatorTree.
 class PostDominatorTreePrinterPass
     : public PassInfoMixin<PostDominatorTreePrinterPass> {
   raw_ostream &OS;