4 files changed, 38 insertions, 6 deletions
diff --git a/include/llvm/Support/CommandLine.h b/include/llvm/Support/CommandLine.h
index 204672f88dd9f..8d4ac81d29429 100644
--- a/include/llvm/Support/CommandLine.h
+++ b/include/llvm/Support/CommandLine.h
@@ -201,7 +201,7 @@ public:
 
   void reset();
 
-  operator bool() const;
+  explicit operator bool() const;
 
   StringRef getName() const { return Name; }
   StringRef getDescription() const { return Description; }
diff --git a/include/llvm/Support/Dwarf.h b/include/llvm/Support/Dwarf.h
index 1a984037da090..8336b9df9df0d 100644
--- a/include/llvm/Support/Dwarf.h
+++ b/include/llvm/Support/Dwarf.h
@@ -207,7 +207,7 @@ enum DiscriminantList {
 };
 
 /// Line Number Standard Opcode Encodings.
-enum LineNumberOps {
+enum LineNumberOps : uint8_t {
 #define HANDLE_DW_LNS(ID, NAME) DW_LNS_##NAME = ID,
 #include "llvm/Support/Dwarf.def"
 };
diff --git a/include/llvm/Support/FileOutputBuffer.h b/include/llvm/Support/FileOutputBuffer.h
index 3bcf64a8a08bd..2c054c75374be 100644
--- a/include/llvm/Support/FileOutputBuffer.h
+++ b/include/llvm/Support/FileOutputBuffer.h
@@ -78,11 +78,12 @@ private:
   FileOutputBuffer &operator=(const FileOutputBuffer &) = delete;
 
   FileOutputBuffer(std::unique_ptr<llvm::sys::fs::mapped_file_region> R,
-                   StringRef Path, StringRef TempPath);
+                   StringRef Path, StringRef TempPath, bool IsRegular);
 
   std::unique_ptr<llvm::sys::fs::mapped_file_region> Region;
   SmallString<128>    FinalPath;
   SmallString<128>    TempPath;
+  bool IsRegular;
 };
 } // end namespace llvm
 
diff --git a/include/llvm/Support/GenericDomTree.h b/include/llvm/Support/GenericDomTree.h
index 07a53438085a0..6e6ee40016440 100644
--- a/include/llvm/Support/GenericDomTree.h
+++ b/include/llvm/Support/GenericDomTree.h
@@ -571,9 +571,15 @@ public:
   // API to update (Post)DominatorTree information based on modifications to
   // the CFG...
 
-  /// addNewBlock - Add a new node to the dominator tree information.  This
-  /// creates a new node as a child of DomBB dominator node,linking it into
-  /// the children list of the immediate dominator.
+  /// Add a new node to the dominator tree information.
+  ///
+  /// This creates a new node as a child of DomBB dominator node, linking it
+  /// into the children list of the immediate dominator.
+  ///
+  /// \param BB New node in CFG.
+  /// \param DomBB CFG node that is dominator for BB.
+  /// \returns New dominator tree node that represents new CFG node.
+  ///
   DomTreeNodeBase<NodeT> *addNewBlock(NodeT *BB, NodeT *DomBB) {
     assert(getNode(BB) == nullptr && "Block already in dominator tree!");
     DomTreeNodeBase<NodeT> *IDomNode = getNode(DomBB);
@@ -583,6 +589,31 @@ public:
                 llvm::make_unique<DomTreeNodeBase<NodeT>>(BB, IDomNode))).get();
   }
 
+  /// Add a new node to the forward dominator tree and make it a new root.
+  ///
+  /// \param BB New node in CFG.
+  /// \returns New dominator tree node that represents new CFG node.
+  ///
+  DomTreeNodeBase<NodeT> *setNewRoot(NodeT *BB) {
+    assert(getNode(BB) == nullptr && "Block already in dominator tree!");
+    assert(!this->isPostDominator() &&
+           "Cannot change root of post-dominator tree");
+    DFSInfoValid = false;
+    auto &Roots = DominatorBase<NodeT>::Roots;
+    DomTreeNodeBase<NodeT> *NewNode = (DomTreeNodes[BB] =
+      llvm::make_unique<DomTreeNodeBase<NodeT>>(BB, nullptr)).get();
+    if (Roots.empty()) {
+      addRoot(BB);
+    } else {
+      assert(Roots.size() == 1);
+      NodeT *OldRoot = Roots.front();
+      DomTreeNodes[OldRoot] =
+        NewNode->addChild(std::move(DomTreeNodes[OldRoot]));
+      Roots[0] = BB;
+    }
+    return RootNode = NewNode;
+  }
+
   /// changeImmediateDominator - This method is used to update the dominator
   /// tree information when a node's immediate dominator changes.
   ///