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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 "llvm/CodeGen/MachineFunctionPass.h"
#include <vector>
namespace llvm {
class MachineFunction;
class MachineModuleInfo;
class RegScavenger;
class TargetInstrInfo;
class TargetRegisterInfo;
class BranchFolder {
public:
explicit BranchFolder(bool defaultEnableTailMerge);
bool OptimizeFunction(MachineFunction &MF,
const TargetInstrInfo *tii,
const TargetRegisterInfo *tri,
MachineModuleInfo *mmi);
private:
typedef std::pair<unsigned,MachineBasicBlock*> MergePotentialsElt;
typedef std::vector<MergePotentialsElt>::iterator MPIterator;
std::vector<MergePotentialsElt> MergePotentials;
typedef std::pair<MPIterator, MachineBasicBlock::iterator> SameTailElt;
std::vector<SameTailElt> SameTails;
bool EnableTailMerge;
const TargetInstrInfo *TII;
const TargetRegisterInfo *TRI;
MachineModuleInfo *MMI;
RegScavenger *RS;
bool TailMergeBlocks(MachineFunction &MF);
bool TryMergeBlocks(MachineBasicBlock* SuccBB,
MachineBasicBlock* PredBB);
void ReplaceTailWithBranchTo(MachineBasicBlock::iterator OldInst,
MachineBasicBlock *NewDest);
MachineBasicBlock *SplitMBBAt(MachineBasicBlock &CurMBB,
MachineBasicBlock::iterator BBI1);
unsigned ComputeSameTails(unsigned CurHash, unsigned minCommonTailLength);
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);
bool CanFallThrough(MachineBasicBlock *CurBB);
bool CanFallThrough(MachineBasicBlock *CurBB, bool BranchUnAnalyzable,
MachineBasicBlock *TBB, MachineBasicBlock *FBB,
const SmallVectorImpl<MachineOperand> &Cond);
};
/// BranchFolderPass - Wrap branch folder in a machine function pass.
class BranchFolderPass : public MachineFunctionPass,
public BranchFolder {
public:
static char ID;
explicit BranchFolderPass(bool defaultEnableTailMerge)
: MachineFunctionPass(&ID), BranchFolder(defaultEnableTailMerge) {}
virtual bool runOnMachineFunction(MachineFunction &MF);
virtual const char *getPassName() const { return "Control Flow Optimizer"; }
};
}
#endif /* LLVM_CODEGEN_BRANCHFOLDING_HPP */
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