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//===-- BranchFolding.h - Fold machine code branch instructions --*- C++ -*===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CODEGEN_BRANCHFOLDING_HPP
#define LLVM_CODEGEN_BRANCHFOLDING_HPP
#include "llvm/CodeGen/MachineBasicBlock.h"
#include <vector>
namespace llvm {
class MachineFunction;
class MachineModuleInfo;
class RegScavenger;
class TargetInstrInfo;
class TargetRegisterInfo;
template<typename T> class SmallVectorImpl;
class BranchFolder {
public:
explicit BranchFolder(bool defaultEnableTailMerge);
bool OptimizeFunction(MachineFunction &MF,
const TargetInstrInfo *tii,
const TargetRegisterInfo *tri,
MachineModuleInfo *mmi);
private:
class MergePotentialsElt {
unsigned Hash;
MachineBasicBlock *Block;
public:
MergePotentialsElt(unsigned h, MachineBasicBlock *b)
: Hash(h), Block(b) {}
unsigned getHash() const { return Hash; }
MachineBasicBlock *getBlock() const { return Block; }
void setBlock(MachineBasicBlock *MBB) {
Block = MBB;
}
bool operator<(const MergePotentialsElt &) const;
};
typedef std::vector<MergePotentialsElt>::iterator MPIterator;
std::vector<MergePotentialsElt> MergePotentials;
class SameTailElt {
MPIterator MPIter;
MachineBasicBlock::iterator TailStartPos;
public:
SameTailElt(MPIterator mp, MachineBasicBlock::iterator tsp)
: MPIter(mp), TailStartPos(tsp) {}
MPIterator getMPIter() const {
return MPIter;
}
MergePotentialsElt &getMergePotentialsElt() const {
return *getMPIter();
}
MachineBasicBlock::iterator getTailStartPos() const {
return TailStartPos;
}
unsigned getHash() const {
return getMergePotentialsElt().getHash();
}
MachineBasicBlock *getBlock() const {
return getMergePotentialsElt().getBlock();
}
bool tailIsWholeBlock() const {
return TailStartPos == getBlock()->begin();
}
void setBlock(MachineBasicBlock *MBB) {
getMergePotentialsElt().setBlock(MBB);
}
void setTailStartPos(MachineBasicBlock::iterator Pos) {
TailStartPos = Pos;
}
};
std::vector<SameTailElt> SameTails;
bool EnableTailMerge;
const TargetInstrInfo *TII;
const TargetRegisterInfo *TRI;
MachineModuleInfo *MMI;
RegScavenger *RS;
bool TailMergeBlocks(MachineFunction &MF);
bool TryTailMergeBlocks(MachineBasicBlock* SuccBB,
MachineBasicBlock* PredBB);
void ReplaceTailWithBranchTo(MachineBasicBlock::iterator OldInst,
MachineBasicBlock *NewDest);
MachineBasicBlock *SplitMBBAt(MachineBasicBlock &CurMBB,
MachineBasicBlock::iterator BBI1);
unsigned ComputeSameTails(unsigned CurHash, unsigned minCommonTailLength,
MachineBasicBlock *SuccBB,
MachineBasicBlock *PredBB);
void RemoveBlocksWithHash(unsigned CurHash, MachineBasicBlock* SuccBB,
MachineBasicBlock* PredBB);
unsigned CreateCommonTailOnlyBlock(MachineBasicBlock *&PredBB,
unsigned maxCommonTailLength);
bool OptimizeBranches(MachineFunction &MF);
bool OptimizeBlock(MachineBasicBlock *MBB);
void RemoveDeadBlock(MachineBasicBlock *MBB);
bool OptimizeImpDefsBlock(MachineBasicBlock *MBB);
};
}
#endif /* LLVM_CODEGEN_BRANCHFOLDING_HPP */
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