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diff --git a/clang-r353983/include/llvm/CodeGen/TailDuplicator.h b/clang-r353983/include/llvm/CodeGen/TailDuplicator.h
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+++ b/clang-r353983/include/llvm/CodeGen/TailDuplicator.h
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+//===- llvm/CodeGen/TailDuplicator.h ----------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines the TailDuplicator class. Used by the
+// TailDuplication pass, and MachineBlockPlacement.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CODEGEN_TAILDUPLICATOR_H
+#define LLVM_CODEGEN_TAILDUPLICATOR_H
+
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/DenseSet.h"
+#include "llvm/ADT/SetVector.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/CodeGen/TargetInstrInfo.h"
+#include <utility>
+#include <vector>
+
+namespace llvm {
+
+class MachineBasicBlock;
+class MachineBranchProbabilityInfo;
+class MachineFunction;
+class MachineInstr;
+class MachineModuleInfo;
+class MachineRegisterInfo;
+class TargetRegisterInfo;
+
+/// Utility class to perform tail duplication.
+class TailDuplicator {
+  const TargetInstrInfo *TII;
+  const TargetRegisterInfo *TRI;
+  const MachineBranchProbabilityInfo *MBPI;
+  const MachineModuleInfo *MMI;
+  MachineRegisterInfo *MRI;
+  MachineFunction *MF;
+  bool PreRegAlloc;
+  bool LayoutMode;
+  unsigned TailDupSize;
+
+  // A list of virtual registers for which to update SSA form.
+  SmallVector<unsigned, 16> SSAUpdateVRs;
+
+  // For each virtual register in SSAUpdateVals keep a list of source virtual
+  // registers.
+  using AvailableValsTy = std::vector<std::pair<MachineBasicBlock *, unsigned>>;
+
+  DenseMap<unsigned, AvailableValsTy> SSAUpdateVals;
+
+public:
+  /// Prepare to run on a specific machine function.
+  /// @param MF - Function that will be processed
+  /// @param PreRegAlloc - true if used before register allocation
+  /// @param MBPI - Branch Probability Info. Used to propagate correct
+  ///     probabilities when modifying the CFG.
+  /// @param LayoutMode - When true, don't use the existing layout to make
+  ///     decisions.
+  /// @param TailDupSize - Maxmimum size of blocks to tail-duplicate. Zero
+  ///     default implies using the command line value TailDupSize.
+  void initMF(MachineFunction &MF, bool PreRegAlloc,
+              const MachineBranchProbabilityInfo *MBPI,
+              bool LayoutMode, unsigned TailDupSize = 0);
+
+  bool tailDuplicateBlocks();
+  static bool isSimpleBB(MachineBasicBlock *TailBB);
+  bool shouldTailDuplicate(bool IsSimple, MachineBasicBlock &TailBB);
+
+  /// Returns true if TailBB can successfully be duplicated into PredBB
+  bool canTailDuplicate(MachineBasicBlock *TailBB, MachineBasicBlock *PredBB);
+
+  /// Tail duplicate a single basic block into its predecessors, and then clean
+  /// up.
+  /// If \p DuplicatePreds is not null, it will be updated to contain the list
+  /// of predecessors that received a copy of \p MBB.
+  /// If \p RemovalCallback is non-null. It will be called before MBB is
+  /// deleted.
+  bool tailDuplicateAndUpdate(
+      bool IsSimple, MachineBasicBlock *MBB,
+      MachineBasicBlock *ForcedLayoutPred,
+      SmallVectorImpl<MachineBasicBlock*> *DuplicatedPreds = nullptr,
+      function_ref<void(MachineBasicBlock *)> *RemovalCallback = nullptr);
+
+private:
+  using RegSubRegPair = TargetInstrInfo::RegSubRegPair;
+
+  void addSSAUpdateEntry(unsigned OrigReg, unsigned NewReg,
+                         MachineBasicBlock *BB);
+  void processPHI(MachineInstr *MI, MachineBasicBlock *TailBB,
+                  MachineBasicBlock *PredBB,
+                  DenseMap<unsigned, RegSubRegPair> &LocalVRMap,
+                  SmallVectorImpl<std::pair<unsigned, RegSubRegPair>> &Copies,
+                  const DenseSet<unsigned> &UsedByPhi, bool Remove);
+  void duplicateInstruction(MachineInstr *MI, MachineBasicBlock *TailBB,
+                            MachineBasicBlock *PredBB,
+                            DenseMap<unsigned, RegSubRegPair> &LocalVRMap,
+                            const DenseSet<unsigned> &UsedByPhi);
+  void updateSuccessorsPHIs(MachineBasicBlock *FromBB, bool isDead,
+                            SmallVectorImpl<MachineBasicBlock *> &TDBBs,
+                            SmallSetVector<MachineBasicBlock *, 8> &Succs);
+  bool canCompletelyDuplicateBB(MachineBasicBlock &BB);
+  bool duplicateSimpleBB(MachineBasicBlock *TailBB,
+                         SmallVectorImpl<MachineBasicBlock *> &TDBBs,
+                         const DenseSet<unsigned> &RegsUsedByPhi,
+                         SmallVectorImpl<MachineInstr *> &Copies);
+  bool tailDuplicate(bool IsSimple,
+                     MachineBasicBlock *TailBB,
+                     MachineBasicBlock *ForcedLayoutPred,
+                     SmallVectorImpl<MachineBasicBlock *> &TDBBs,
+                     SmallVectorImpl<MachineInstr *> &Copies);
+  void appendCopies(MachineBasicBlock *MBB,
+                 SmallVectorImpl<std::pair<unsigned,RegSubRegPair>> &CopyInfos,
+                 SmallVectorImpl<MachineInstr *> &Copies);
+
+  void removeDeadBlock(
+      MachineBasicBlock *MBB,
+      function_ref<void(MachineBasicBlock *)> *RemovalCallback = nullptr);
+};
+
+} // end namespace llvm
+
+#endif // LLVM_CODEGEN_TAILDUPLICATOR_H