1 //===-- llvm/CodeGen/TailDuplicator.h ---------------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines the TailDuplicator class. Used by the
11 // TailDuplication pass, and MachineBlockPlacement.
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_CODEGEN_TAILDUPLICATOR_H
16 #define LLVM_CODEGEN_TAILDUPLICATOR_H
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"
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;
38 // A list of virtual registers for which to update SSA form.
39 SmallVector<unsigned, 16> SSAUpdateVRs;
41 // For each virtual register in SSAUpdateVals keep a list of source virtual
43 typedef std::vector<std::pair<MachineBasicBlock *, unsigned>> AvailableValsTy;
45 DenseMap<unsigned, AvailableValsTy> SSAUpdateVals;
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);
58 typedef TargetInstrInfo::RegSubRegPair RegSubRegPair;
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);
87 void removeDeadBlock(MachineBasicBlock *MBB);
90 } // End llvm namespace