contrib/llvm/include/llvm/CodeGen/TailDuplicator.h

   1 //===-- llvm/CodeGen/TailDuplicator.h ---------------------------*- C++ -*-===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file defines the TailDuplicator class. Used by the
  11 // TailDuplication pass, and MachineBlockPlacement.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #ifndef LLVM_CODEGEN_TAILDUPLICATOR_H
  16 #define LLVM_CODEGEN_TAILDUPLICATOR_H
  17
  18 #include "llvm/CodeGen/MachineBranchProbabilityInfo.h"
  19 #include "llvm/CodeGen/MachineModuleInfo.h"
  20 #include "llvm/CodeGen/MachineRegisterInfo.h"
  21 #include "llvm/CodeGen/MachineSSAUpdater.h"
  22 #include "llvm/CodeGen/RegisterScavenging.h"
  23 #include "llvm/Target/TargetInstrInfo.h"
  24 #include "llvm/Target/TargetRegisterInfo.h"
  25 #include "llvm/Target/TargetSubtargetInfo.h"
  26
  27 namespace llvm {
  28
  29 /// Utility class to perform tail duplication.
  30 class TailDuplicator {
  31   const TargetInstrInfo *TII;
  32   const TargetRegisterInfo *TRI;
  33   const MachineBranchProbabilityInfo *MBPI;
  34   const MachineModuleInfo *MMI;
  35   MachineRegisterInfo *MRI;
  36   bool PreRegAlloc;
  37
  38   // A list of virtual registers for which to update SSA form.
  39   SmallVector<unsigned, 16> SSAUpdateVRs;
  40
  41   // For each virtual register in SSAUpdateVals keep a list of source virtual
  42   // registers.
  43   typedef std::vector<std::pair<MachineBasicBlock *, unsigned>> AvailableValsTy;
  44
  45   DenseMap<unsigned, AvailableValsTy> SSAUpdateVals;
  46
  47 public:
  48   void initMF(MachineFunction &MF, const MachineModuleInfo *MMI,
  49               const MachineBranchProbabilityInfo *MBPI);
  50   bool tailDuplicateBlocks(MachineFunction &MF);
  51   static bool isSimpleBB(MachineBasicBlock *TailBB);
  52   bool shouldTailDuplicate(const MachineFunction &MF, bool IsSimple,
  53                            MachineBasicBlock &TailBB);
  54   bool tailDuplicateAndUpdate(MachineFunction &MF, bool IsSimple,
  55                               MachineBasicBlock *MBB);
  56
  57 private:
  58   typedef TargetInstrInfo::RegSubRegPair RegSubRegPair;
  59
  60   void addSSAUpdateEntry(unsigned OrigReg, unsigned NewReg,
  61                          MachineBasicBlock *BB);
  62   void processPHI(MachineInstr *MI, MachineBasicBlock *TailBB,
  63                   MachineBasicBlock *PredBB,
  64                   DenseMap<unsigned, RegSubRegPair> &LocalVRMap,
  65                   SmallVectorImpl<std::pair<unsigned, RegSubRegPair>> &Copies,
  66                   const DenseSet<unsigned> &UsedByPhi, bool Remove);
  67   void duplicateInstruction(MachineInstr *MI, MachineBasicBlock *TailBB,
  68                             MachineBasicBlock *PredBB, MachineFunction &MF,
  69                             DenseMap<unsigned, RegSubRegPair> &LocalVRMap,
  70                             const DenseSet<unsigned> &UsedByPhi);
  71   void updateSuccessorsPHIs(MachineBasicBlock *FromBB, bool isDead,
  72                             SmallVectorImpl<MachineBasicBlock *> &TDBBs,
  73                             SmallSetVector<MachineBasicBlock *, 8> &Succs);
  74   bool canCompletelyDuplicateBB(MachineBasicBlock &BB);
  75   bool duplicateSimpleBB(MachineBasicBlock *TailBB,
  76                          SmallVectorImpl<MachineBasicBlock *> &TDBBs,
  77                          const DenseSet<unsigned> &RegsUsedByPhi,
  78                          SmallVectorImpl<MachineInstr *> &Copies);
  79   bool tailDuplicate(MachineFunction &MF, bool IsSimple,
  80                      MachineBasicBlock *TailBB,
  81                      SmallVectorImpl<MachineBasicBlock *> &TDBBs,
  82                      SmallVectorImpl<MachineInstr *> &Copies);
  83   void appendCopies(MachineBasicBlock *MBB,
  84                  SmallVectorImpl<std::pair<unsigned,RegSubRegPair>> &CopyInfos,
  85                  SmallVectorImpl<MachineInstr *> &Copies);
  86
  87   void removeDeadBlock(MachineBasicBlock *MBB);
  88 };
  89
  90 } // End llvm namespace
  91
  92 #endif