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