include/llvm/CodeGen/LiveIntervalAnalysis.h - llvm - Git at Google

 //===-- LiveIntervalAnalysis.h - Live Interval Analysis ---------*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file implements the LiveInterval analysis pass.  Given some numbering of
 // each the machine instructions (in this implemention depth-first order) an
 // interval [i, j) is said to be a live interval for register v if there is no
 // instruction with number j' > j such that v is live at j' and there is no
 // instruction with number i' < i such that v is live at i'. In this
 // implementation intervals can have holes, i.e. an interval might look like
 // [1,20), [50,65), [1000,1001).
 //
 //===----------------------------------------------------------------------===//

 #ifndef LLVM_CODEGEN_LIVEINTERVAL_ANALYSIS_H
 #define LLVM_CODEGEN_LIVEINTERVAL_ANALYSIS_H

 #include "llvm/CodeGen/MachineBasicBlock.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
 #include "llvm/CodeGen/LiveInterval.h"
 #include "llvm/CodeGen/SlotIndexes.h"
 #include "llvm/ADT/BitVector.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/Support/Allocator.h"
 #include <cmath>
 #include <iterator>

 namespace llvm {

   class AliasAnalysis;
   class LiveVariables;
   class MachineLoopInfo;
   class TargetRegisterInfo;
   class MachineRegisterInfo;
   class TargetInstrInfo;
   class TargetRegisterClass;
   class VirtRegMap;

   class LiveIntervals : public MachineFunctionPass {
     MachineFunction* mf_;
     MachineRegisterInfo* mri_;
     const TargetMachine* tm_;
     const TargetRegisterInfo* tri_;
     const TargetInstrInfo* tii_;
     AliasAnalysis *aa_;
     LiveVariables* lv_;
     SlotIndexes* indexes_;

     /// Special pool allocator for VNInfo's (LiveInterval val#).
     ///
     VNInfo::Allocator VNInfoAllocator;

     typedef DenseMap<unsigned, LiveInterval*> Reg2IntervalMap;
     Reg2IntervalMap r2iMap_;

     /// allocatableRegs_ - A bit vector of allocatable registers.
     BitVector allocatableRegs_;

     /// CloneMIs - A list of clones as result of re-materialization.
     std::vector<MachineInstr*> CloneMIs;

   public:
     static char ID; // Pass identification, replacement for typeid
     LiveIntervals() : MachineFunctionPass(ID) {
       initializeLiveIntervalsPass(*PassRegistry::getPassRegistry());
     }

     // Calculate the spill weight to assign to a single instruction.
     static float getSpillWeight(bool isDef, bool isUse, unsigned loopDepth);

     typedef Reg2IntervalMap::iterator iterator;
     typedef Reg2IntervalMap::const_iterator const_iterator;
     const_iterator begin() const { return r2iMap_.begin(); }
     const_iterator end() const { return r2iMap_.end(); }
     iterator begin() { return r2iMap_.begin(); }
     iterator end() { return r2iMap_.end(); }
     unsigned getNumIntervals() const { return (unsigned)r2iMap_.size(); }

     LiveInterval &getInterval(unsigned reg) {
       Reg2IntervalMap::iterator I = r2iMap_.find(reg);
       assert(I != r2iMap_.end() && "Interval does not exist for register");
       return *I->second;
     }

     const LiveInterval &getInterval(unsigned reg) const {
       Reg2IntervalMap::const_iterator I = r2iMap_.find(reg);
       assert(I != r2iMap_.end() && "Interval does not exist for register");
       return *I->second;
     }

     bool hasInterval(unsigned reg) const {
       return r2iMap_.count(reg);
     }

     /// isAllocatable - is the physical register reg allocatable in the current
     /// function?
     bool isAllocatable(unsigned reg) const {
       return allocatableRegs_.test(reg);
     }

     /// getScaledIntervalSize - get the size of an interval in "units,"
     /// where every function is composed of one thousand units.  This
     /// measure scales properly with empty index slots in the function.
     double getScaledIntervalSize(LiveInterval& I) {
       return (1000.0 * I.getSize()) / indexes_->getIndexesLength();
     }

     /// getFuncInstructionCount - Return the number of instructions in the
     /// current function.
     unsigned getFuncInstructionCount() {
       return indexes_->getFunctionSize();
     }

     /// getApproximateInstructionCount - computes an estimate of the number
     /// of instructions in a given LiveInterval.
     unsigned getApproximateInstructionCount(LiveInterval& I) {
       double IntervalPercentage = getScaledIntervalSize(I) / 1000.0;
       return (unsigned)(IntervalPercentage * indexes_->getFunctionSize());
     }

     /// conflictsWithPhysReg - Returns true if the specified register is used or
     /// defined during the duration of the specified interval. Copies to and
     /// from li.reg are allowed. This method is only able to analyze simple
     /// ranges that stay within a single basic block. Anything else is
     /// considered a conflict.
     bool conflictsWithPhysReg(const LiveInterval &li, VirtRegMap &vrm,
                               unsigned reg);

     /// conflictsWithAliasRef - Similar to conflictsWithPhysRegRef except
     /// it checks for alias uses and defs.
     bool conflictsWithAliasRef(LiveInterval &li, unsigned Reg,
                                    SmallPtrSet<MachineInstr*,32> &JoinedCopies);

     // Interval creation
     LiveInterval &getOrCreateInterval(unsigned reg) {
       Reg2IntervalMap::iterator I = r2iMap_.find(reg);
       if (I == r2iMap_.end())
         I = r2iMap_.insert(std::make_pair(reg, createInterval(reg))).first;
       return *I->second;
     }

     /// dupInterval - Duplicate a live interval. The caller is responsible for
     /// managing the allocated memory.
     LiveInterval *dupInterval(LiveInterval *li);

     /// addLiveRangeToEndOfBlock - Given a register and an instruction,
     /// adds a live range from that instruction to the end of its MBB.
     LiveRange addLiveRangeToEndOfBlock(unsigned reg,
                                        MachineInstr* startInst);

     /// shrinkToUses - After removing some uses of a register, shrink its live
     /// range to just the remaining uses. This method does not compute reaching
     /// defs for new uses, and it doesn't remove dead defs.
     /// Dead PHIDef values are marked as unused.
     /// New dead machine instructions are added to the dead vector.
     /// Return true if the interval may have been separated into multiple
     /// connected components.
     bool shrinkToUses(LiveInterval *li,
                       SmallVectorImpl<MachineInstr*> *dead = 0);

     // Interval removal

     void removeInterval(unsigned Reg) {
       DenseMap<unsigned, LiveInterval*>::iterator I = r2iMap_.find(Reg);
       delete I->second;
       r2iMap_.erase(I);
     }

     SlotIndexes *getSlotIndexes() const {
       return indexes_;
     }

     SlotIndex getZeroIndex() const {
       return indexes_->getZeroIndex();
     }

     SlotIndex getInvalidIndex() const {
       return indexes_->getInvalidIndex();
     }

     /// isNotInMIMap - returns true if the specified machine instr has been
     /// removed or was never entered in the map.
     bool isNotInMIMap(const MachineInstr* Instr) const {
       return !indexes_->hasIndex(Instr);
     }

     /// Returns the base index of the given instruction.
     SlotIndex getInstructionIndex(const MachineInstr *instr) const {
       return indexes_->getInstructionIndex(instr);
     }

     /// Returns the instruction associated with the given index.
     MachineInstr* getInstructionFromIndex(SlotIndex index) const {
       return indexes_->getInstructionFromIndex(index);
     }

     /// Return the first index in the given basic block.
     SlotIndex getMBBStartIdx(const MachineBasicBlock *mbb) const {
       return indexes_->getMBBStartIdx(mbb);
     }

     /// Return the last index in the given basic block.
     SlotIndex getMBBEndIdx(const MachineBasicBlock *mbb) const {
       return indexes_->getMBBEndIdx(mbb);
     }

     bool isLiveInToMBB(const LiveInterval &li,
                        const MachineBasicBlock *mbb) const {
       return li.liveAt(getMBBStartIdx(mbb));
     }

     LiveRange* findEnteringRange(LiveInterval &li,
                                  const MachineBasicBlock *mbb) {
       return li.getLiveRangeContaining(getMBBStartIdx(mbb));
     }

     bool isLiveOutOfMBB(const LiveInterval &li,
                         const MachineBasicBlock *mbb) const {
       return li.liveAt(getMBBEndIdx(mbb).getPrevSlot());
     }

     LiveRange* findExitingRange(LiveInterval &li,
                                 const MachineBasicBlock *mbb) {
       return li.getLiveRangeContaining(getMBBEndIdx(mbb).getPrevSlot());
     }

     MachineBasicBlock* getMBBFromIndex(SlotIndex index) const {
       return indexes_->getMBBFromIndex(index);
     }

     SlotIndex InsertMachineInstrInMaps(MachineInstr *MI) {
       return indexes_->insertMachineInstrInMaps(MI);
     }

     void RemoveMachineInstrFromMaps(MachineInstr *MI) {
       indexes_->removeMachineInstrFromMaps(MI);
     }

     void ReplaceMachineInstrInMaps(MachineInstr *MI, MachineInstr *NewMI) {
       indexes_->replaceMachineInstrInMaps(MI, NewMI);
     }

     void InsertMBBInMaps(MachineBasicBlock *MBB) {
       indexes_->insertMBBInMaps(MBB);
     }

     bool findLiveInMBBs(SlotIndex Start, SlotIndex End,
                         SmallVectorImpl<MachineBasicBlock*> &MBBs) const {
       return indexes_->findLiveInMBBs(Start, End, MBBs);
     }

     void renumber() {
       indexes_->renumberIndexes();
     }

     VNInfo::Allocator& getVNInfoAllocator() { return VNInfoAllocator; }

     virtual void getAnalysisUsage(AnalysisUsage &AU) const;
     virtual void releaseMemory();

     /// runOnMachineFunction - pass entry point
     virtual bool runOnMachineFunction(MachineFunction&);

     /// print - Implement the dump method.
     virtual void print(raw_ostream &O, const Module* = 0) const;

     /// addIntervalsForSpills - Create new intervals for spilled defs / uses of
     /// the given interval. FIXME: It also returns the weight of the spill slot
     /// (if any is created) by reference. This is temporary.
     std::vector<LiveInterval*>
     addIntervalsForSpills(const LiveInterval& i,
                           const SmallVectorImpl<LiveInterval*> *SpillIs,
                           const MachineLoopInfo *loopInfo, VirtRegMap& vrm);

     /// spillPhysRegAroundRegDefsUses - Spill the specified physical register
     /// around all defs and uses of the specified interval. Return true if it
     /// was able to cut its interval.
     bool spillPhysRegAroundRegDefsUses(const LiveInterval &li,
                                        unsigned PhysReg, VirtRegMap &vrm);

     /// isReMaterializable - Returns true if every definition of MI of every
     /// val# of the specified interval is re-materializable. Also returns true
     /// by reference if all of the defs are load instructions.
     bool isReMaterializable(const LiveInterval &li,
                             const SmallVectorImpl<LiveInterval*> *SpillIs,
                             bool &isLoad);

     /// isReMaterializable - Returns true if the definition MI of the specified
     /// val# of the specified interval is re-materializable.
     bool isReMaterializable(const LiveInterval &li, const VNInfo *ValNo,
                             MachineInstr *MI);

     /// getRepresentativeReg - Find the largest super register of the specified
     /// physical register.
     unsigned getRepresentativeReg(unsigned Reg) const;

     /// getNumConflictsWithPhysReg - Return the number of uses and defs of the
     /// specified interval that conflicts with the specified physical register.
     unsigned getNumConflictsWithPhysReg(const LiveInterval &li,
                                         unsigned PhysReg) const;

     /// intervalIsInOneMBB - Returns true if the specified interval is entirely
     /// within a single basic block.
     bool intervalIsInOneMBB(const LiveInterval &li) const;

     /// getLastSplitPoint - Return the last possible insertion point in mbb for
     /// spilling and splitting code. This is the first terminator, or the call
     /// instruction if li is live into a landing pad successor.
     MachineBasicBlock::iterator getLastSplitPoint(const LiveInterval &li,
                                                   MachineBasicBlock *mbb) const;

     /// addKillFlags - Add kill flags to any instruction that kills a virtual
     /// register.
     void addKillFlags();

   private:
     /// computeIntervals - Compute live intervals.
     void computeIntervals();

     /// handleRegisterDef - update intervals for a register def
     /// (calls handlePhysicalRegisterDef and
     /// handleVirtualRegisterDef)
     void handleRegisterDef(MachineBasicBlock *MBB,
                            MachineBasicBlock::iterator MI,
                            SlotIndex MIIdx,
                            MachineOperand& MO, unsigned MOIdx);

     /// isPartialRedef - Return true if the specified def at the specific index
     /// is partially re-defining the specified live interval. A common case of
     /// this is a definition of the sub-register.
     bool isPartialRedef(SlotIndex MIIdx, MachineOperand &MO,
                         LiveInterval &interval);

     /// handleVirtualRegisterDef - update intervals for a virtual
     /// register def
     void handleVirtualRegisterDef(MachineBasicBlock *MBB,
                                   MachineBasicBlock::iterator MI,
                                   SlotIndex MIIdx, MachineOperand& MO,
                                   unsigned MOIdx,
                                   LiveInterval& interval);

     /// handlePhysicalRegisterDef - update intervals for a physical register
     /// def.
     void handlePhysicalRegisterDef(MachineBasicBlock* mbb,
                                    MachineBasicBlock::iterator mi,
                                    SlotIndex MIIdx, MachineOperand& MO,
                                    LiveInterval &interval,
                                    MachineInstr *CopyMI);

     /// handleLiveInRegister - Create interval for a livein register.
     void handleLiveInRegister(MachineBasicBlock* mbb,
                               SlotIndex MIIdx,
                               LiveInterval &interval, bool isAlias = false);

     /// getReMatImplicitUse - If the remat definition MI has one (for now, we
     /// only allow one) virtual register operand, then its uses are implicitly
     /// using the register. Returns the virtual register.
     unsigned getReMatImplicitUse(const LiveInterval &li,
                                  MachineInstr *MI) const;

     /// isValNoAvailableAt - Return true if the val# of the specified interval
     /// which reaches the given instruction also reaches the specified use
     /// index.
     bool isValNoAvailableAt(const LiveInterval &li, MachineInstr *MI,
                             SlotIndex UseIdx) const;

     /// isReMaterializable - Returns true if the definition MI of the specified
     /// val# of the specified interval is re-materializable. Also returns true
     /// by reference if the def is a load.
     bool isReMaterializable(const LiveInterval &li, const VNInfo *ValNo,
                             MachineInstr *MI,
                             const SmallVectorImpl<LiveInterval*> *SpillIs,
                             bool &isLoad);

     /// tryFoldMemoryOperand - Attempts to fold either a spill / restore from
     /// slot / to reg or any rematerialized load into ith operand of specified
     /// MI. If it is successul, MI is updated with the newly created MI and
     /// returns true.
     bool tryFoldMemoryOperand(MachineInstr* &MI, VirtRegMap &vrm,
                               MachineInstr *DefMI, SlotIndex InstrIdx,
                               SmallVector<unsigned, 2> &Ops,
                               bool isSS, int FrameIndex, unsigned Reg);

     /// canFoldMemoryOperand - Return true if the specified load / store
     /// folding is possible.
     bool canFoldMemoryOperand(MachineInstr *MI,
                               SmallVector<unsigned, 2> &Ops,
                               bool ReMatLoadSS) const;

     /// anyKillInMBBAfterIdx - Returns true if there is a kill of the specified
     /// VNInfo that's after the specified index but is within the basic block.
     bool anyKillInMBBAfterIdx(const LiveInterval &li, const VNInfo *VNI,
                               MachineBasicBlock *MBB,
                               SlotIndex Idx) const;

     /// hasAllocatableSuperReg - Return true if the specified physical register
     /// has any super register that's allocatable.
     bool hasAllocatableSuperReg(unsigned Reg) const;

     /// SRInfo - Spill / restore info.
     struct SRInfo {
       SlotIndex index;
       unsigned vreg;
       bool canFold;
       SRInfo(SlotIndex i, unsigned vr, bool f)
         : index(i), vreg(vr), canFold(f) {}
     };

     bool alsoFoldARestore(int Id, SlotIndex index, unsigned vr,
                           BitVector &RestoreMBBs,
                           DenseMap<unsigned,std::vector<SRInfo> >&RestoreIdxes);
     void eraseRestoreInfo(int Id, SlotIndex index, unsigned vr,
                           BitVector &RestoreMBBs,
                           DenseMap<unsigned,std::vector<SRInfo> >&RestoreIdxes);

     /// handleSpilledImpDefs - Remove IMPLICIT_DEF instructions which are being
     /// spilled and create empty intervals for their uses.
     void handleSpilledImpDefs(const LiveInterval &li, VirtRegMap &vrm,
                               const TargetRegisterClass* rc,
                               std::vector<LiveInterval*> &NewLIs);

     /// rewriteImplicitOps - Rewrite implicit use operands of MI (i.e. uses of
     /// interval on to-be re-materialized operands of MI) with new register.
     void rewriteImplicitOps(const LiveInterval &li,
                            MachineInstr *MI, unsigned NewVReg, VirtRegMap &vrm);

     /// rewriteInstructionForSpills, rewriteInstructionsForSpills - Helper
     /// functions for addIntervalsForSpills to rewrite uses / defs for the given
     /// live range.
     bool rewriteInstructionForSpills(const LiveInterval &li, const VNInfo *VNI,
         bool TrySplit, SlotIndex index, SlotIndex end,
         MachineInstr *MI, MachineInstr *OrigDefMI, MachineInstr *DefMI,
         unsigned Slot, int LdSlot,
         bool isLoad, bool isLoadSS, bool DefIsReMat, bool CanDelete,
         VirtRegMap &vrm, const TargetRegisterClass* rc,
         SmallVector<int, 4> &ReMatIds, const MachineLoopInfo *loopInfo,
         unsigned &NewVReg, unsigned ImpUse, bool &HasDef, bool &HasUse,
         DenseMap<unsigned,unsigned> &MBBVRegsMap,
         std::vector<LiveInterval*> &NewLIs);
     void rewriteInstructionsForSpills(const LiveInterval &li, bool TrySplit,
         LiveInterval::Ranges::const_iterator &I,
         MachineInstr *OrigDefMI, MachineInstr *DefMI, unsigned Slot, int LdSlot,
         bool isLoad, bool isLoadSS, bool DefIsReMat, bool CanDelete,
         VirtRegMap &vrm, const TargetRegisterClass* rc,
         SmallVector<int, 4> &ReMatIds, const MachineLoopInfo *loopInfo,
         BitVector &SpillMBBs,
         DenseMap<unsigned,std::vector<SRInfo> > &SpillIdxes,
         BitVector &RestoreMBBs,
         DenseMap<unsigned,std::vector<SRInfo> > &RestoreIdxes,
         DenseMap<unsigned,unsigned> &MBBVRegsMap,
         std::vector<LiveInterval*> &NewLIs);

     static LiveInterval* createInterval(unsigned Reg);

     void printInstrs(raw_ostream &O) const;
     void dumpInstrs() const;
   };
 } // End llvm namespace

 #endif
	//===-- LiveIntervalAnalysis.h - Live Interval Analysis ---------- C++ --===//
	//
	// The LLVM Compiler Infrastructure
	//
	// This file is distributed under the University of Illinois Open Source
	// License. See LICENSE.TXT for details.
	//
	//===----------------------------------------------------------------------===//
	//
	// This file implements the LiveInterval analysis pass. Given some numbering of
	// each the machine instructions (in this implemention depth-first order) an
	// interval [i, j) is said to be a live interval for register v if there is no
	// instruction with number j' > j such that v is live at j' and there is no
	// instruction with number i' < i such that v is live at i'. In this
	// implementation intervals can have holes, i.e. an interval might look like
	// [1,20), [50,65), [1000,1001).
	//
	//===----------------------------------------------------------------------===//

	#ifndef LLVM_CODEGEN_LIVEINTERVAL_ANALYSIS_H
	#define LLVM_CODEGEN_LIVEINTERVAL_ANALYSIS_H

	#include "llvm/CodeGen/MachineBasicBlock.h"
	#include "llvm/CodeGen/MachineFunctionPass.h"
	#include "llvm/CodeGen/LiveInterval.h"
	#include "llvm/CodeGen/SlotIndexes.h"
	#include "llvm/ADT/BitVector.h"
	#include "llvm/ADT/DenseMap.h"
	#include "llvm/ADT/SmallPtrSet.h"
	#include "llvm/ADT/SmallVector.h"
	#include "llvm/Support/Allocator.h"
	#include <cmath>
	#include <iterator>

	namespace llvm {

	class AliasAnalysis;
	class LiveVariables;
	class MachineLoopInfo;
	class TargetRegisterInfo;
	class MachineRegisterInfo;
	class TargetInstrInfo;
	class TargetRegisterClass;
	class VirtRegMap;

	class LiveIntervals : public MachineFunctionPass {
	MachineFunction* mf_;
	MachineRegisterInfo* mri_;
	const TargetMachine* tm_;
	const TargetRegisterInfo* tri_;
	const TargetInstrInfo* tii_;
	AliasAnalysis *aa_;
	LiveVariables* lv_;
	SlotIndexes* indexes_;

	/// Special pool allocator for VNInfo's (LiveInterval val#).
	///
	VNInfo::Allocator VNInfoAllocator;

	typedef DenseMap<unsigned, LiveInterval*> Reg2IntervalMap;
	Reg2IntervalMap r2iMap_;

	/// allocatableRegs_ - A bit vector of allocatable registers.
	BitVector allocatableRegs_;

	/// CloneMIs - A list of clones as result of re-materialization.
	std::vector<MachineInstr*> CloneMIs;

	public:
	static char ID; // Pass identification, replacement for typeid
	LiveIntervals() : MachineFunctionPass(ID) {
	initializeLiveIntervalsPass(*PassRegistry::getPassRegistry());
	}

	// Calculate the spill weight to assign to a single instruction.
	static float getSpillWeight(bool isDef, bool isUse, unsigned loopDepth);

	typedef Reg2IntervalMap::iterator iterator;
	typedef Reg2IntervalMap::const_iterator const_iterator;
	const_iterator begin() const { return r2iMap_.begin(); }
	const_iterator end() const { return r2iMap_.end(); }
	iterator begin() { return r2iMap_.begin(); }
	iterator end() { return r2iMap_.end(); }
	unsigned getNumIntervals() const { return (unsigned)r2iMap_.size(); }

	LiveInterval &getInterval(unsigned reg) {
	Reg2IntervalMap::iterator I = r2iMap_.find(reg);
	assert(I != r2iMap_.end() && "Interval does not exist for register");
	return *I->second;
	}

	const LiveInterval &getInterval(unsigned reg) const {
	Reg2IntervalMap::const_iterator I = r2iMap_.find(reg);
	assert(I != r2iMap_.end() && "Interval does not exist for register");
	return *I->second;
	}

	bool hasInterval(unsigned reg) const {
	return r2iMap_.count(reg);
	}

	/// isAllocatable - is the physical register reg allocatable in the current
	/// function?
	bool isAllocatable(unsigned reg) const {
	return allocatableRegs_.test(reg);
	}

	/// getScaledIntervalSize - get the size of an interval in "units,"
	/// where every function is composed of one thousand units. This
	/// measure scales properly with empty index slots in the function.
	double getScaledIntervalSize(LiveInterval& I) {
	return (1000.0 * I.getSize()) / indexes_->getIndexesLength();
	}

	/// getFuncInstructionCount - Return the number of instructions in the
	/// current function.
	unsigned getFuncInstructionCount() {
	return indexes_->getFunctionSize();
	}

	/// getApproximateInstructionCount - computes an estimate of the number
	/// of instructions in a given LiveInterval.
	unsigned getApproximateInstructionCount(LiveInterval& I) {
	double IntervalPercentage = getScaledIntervalSize(I) / 1000.0;
	return (unsigned)(IntervalPercentage * indexes_->getFunctionSize());
	}

	/// conflictsWithPhysReg - Returns true if the specified register is used or
	/// defined during the duration of the specified interval. Copies to and
	/// from li.reg are allowed. This method is only able to analyze simple
	/// ranges that stay within a single basic block. Anything else is
	/// considered a conflict.
	bool conflictsWithPhysReg(const LiveInterval &li, VirtRegMap &vrm,
	unsigned reg);

	/// conflictsWithAliasRef - Similar to conflictsWithPhysRegRef except
	/// it checks for alias uses and defs.
	bool conflictsWithAliasRef(LiveInterval &li, unsigned Reg,
	SmallPtrSet<MachineInstr*,32> &JoinedCopies);

	// Interval creation
	LiveInterval &getOrCreateInterval(unsigned reg) {
	Reg2IntervalMap::iterator I = r2iMap_.find(reg);
	if (I == r2iMap_.end())
	I = r2iMap_.insert(std::make_pair(reg, createInterval(reg))).first;
	return *I->second;
	}

	/// dupInterval - Duplicate a live interval. The caller is responsible for
	/// managing the allocated memory.
	LiveInterval dupInterval(LiveInterval li);

	/// addLiveRangeToEndOfBlock - Given a register and an instruction,
	/// adds a live range from that instruction to the end of its MBB.
	LiveRange addLiveRangeToEndOfBlock(unsigned reg,
	MachineInstr* startInst);

	/// shrinkToUses - After removing some uses of a register, shrink its live
	/// range to just the remaining uses. This method does not compute reaching
	/// defs for new uses, and it doesn't remove dead defs.
	/// Dead PHIDef values are marked as unused.
	/// New dead machine instructions are added to the dead vector.
	/// Return true if the interval may have been separated into multiple
	/// connected components.
	bool shrinkToUses(LiveInterval *li,
	SmallVectorImpl<MachineInstr> dead = 0);

	// Interval removal

	void removeInterval(unsigned Reg) {
	DenseMap<unsigned, LiveInterval*>::iterator I = r2iMap_.find(Reg);
	delete I->second;
	r2iMap_.erase(I);
	}

	SlotIndexes *getSlotIndexes() const {
	return indexes_;
	}

	SlotIndex getZeroIndex() const {
	return indexes_->getZeroIndex();
	}

	SlotIndex getInvalidIndex() const {
	return indexes_->getInvalidIndex();
	}

	/// isNotInMIMap - returns true if the specified machine instr has been
	/// removed or was never entered in the map.
	bool isNotInMIMap(const MachineInstr* Instr) const {
	return !indexes_->hasIndex(Instr);
	}

	/// Returns the base index of the given instruction.
	SlotIndex getInstructionIndex(const MachineInstr *instr) const {
	return indexes_->getInstructionIndex(instr);
	}

	/// Returns the instruction associated with the given index.
	MachineInstr* getInstructionFromIndex(SlotIndex index) const {
	return indexes_->getInstructionFromIndex(index);
	}

	/// Return the first index in the given basic block.
	SlotIndex getMBBStartIdx(const MachineBasicBlock *mbb) const {
	return indexes_->getMBBStartIdx(mbb);
	}

	/// Return the last index in the given basic block.
	SlotIndex getMBBEndIdx(const MachineBasicBlock *mbb) const {
	return indexes_->getMBBEndIdx(mbb);
	}

	bool isLiveInToMBB(const LiveInterval &li,
	const MachineBasicBlock *mbb) const {
	return li.liveAt(getMBBStartIdx(mbb));
	}

	LiveRange* findEnteringRange(LiveInterval &li,
	const MachineBasicBlock *mbb) {
	return li.getLiveRangeContaining(getMBBStartIdx(mbb));
	}

	bool isLiveOutOfMBB(const LiveInterval &li,
	const MachineBasicBlock *mbb) const {
	return li.liveAt(getMBBEndIdx(mbb).getPrevSlot());
	}

	LiveRange* findExitingRange(LiveInterval &li,
	const MachineBasicBlock *mbb) {
	return li.getLiveRangeContaining(getMBBEndIdx(mbb).getPrevSlot());
	}

	MachineBasicBlock* getMBBFromIndex(SlotIndex index) const {
	return indexes_->getMBBFromIndex(index);
	}

	SlotIndex InsertMachineInstrInMaps(MachineInstr *MI) {
	return indexes_->insertMachineInstrInMaps(MI);
	}

	void RemoveMachineInstrFromMaps(MachineInstr *MI) {
	indexes_->removeMachineInstrFromMaps(MI);
	}

	void ReplaceMachineInstrInMaps(MachineInstr MI, MachineInstr NewMI) {
	indexes_->replaceMachineInstrInMaps(MI, NewMI);
	}

	void InsertMBBInMaps(MachineBasicBlock *MBB) {
	indexes_->insertMBBInMaps(MBB);
	}

	bool findLiveInMBBs(SlotIndex Start, SlotIndex End,
	SmallVectorImpl<MachineBasicBlock*> &MBBs) const {
	return indexes_->findLiveInMBBs(Start, End, MBBs);
	}

	void renumber() {
	indexes_->renumberIndexes();
	}

	VNInfo::Allocator& getVNInfoAllocator() { return VNInfoAllocator; }

	virtual void getAnalysisUsage(AnalysisUsage &AU) const;
	virtual void releaseMemory();

	/// runOnMachineFunction - pass entry point
	virtual bool runOnMachineFunction(MachineFunction&);

	/// print - Implement the dump method.
	virtual void print(raw_ostream &O, const Module* = 0) const;

	/// addIntervalsForSpills - Create new intervals for spilled defs / uses of
	/// the given interval. FIXME: It also returns the weight of the spill slot
	/// (if any is created) by reference. This is temporary.
	std::vector<LiveInterval*>
	addIntervalsForSpills(const LiveInterval& i,
	const SmallVectorImpl<LiveInterval> SpillIs,
	const MachineLoopInfo *loopInfo, VirtRegMap& vrm);

	/// spillPhysRegAroundRegDefsUses - Spill the specified physical register
	/// around all defs and uses of the specified interval. Return true if it
	/// was able to cut its interval.
	bool spillPhysRegAroundRegDefsUses(const LiveInterval &li,
	unsigned PhysReg, VirtRegMap &vrm);

	/// isReMaterializable - Returns true if every definition of MI of every
	/// val# of the specified interval is re-materializable. Also returns true
	/// by reference if all of the defs are load instructions.
	bool isReMaterializable(const LiveInterval &li,
	const SmallVectorImpl<LiveInterval> SpillIs,
	bool &isLoad);

	/// isReMaterializable - Returns true if the definition MI of the specified
	/// val# of the specified interval is re-materializable.
	bool isReMaterializable(const LiveInterval &li, const VNInfo *ValNo,
	MachineInstr *MI);

	/// getRepresentativeReg - Find the largest super register of the specified
	/// physical register.
	unsigned getRepresentativeReg(unsigned Reg) const;

	/// getNumConflictsWithPhysReg - Return the number of uses and defs of the
	/// specified interval that conflicts with the specified physical register.
	unsigned getNumConflictsWithPhysReg(const LiveInterval &li,
	unsigned PhysReg) const;

	/// intervalIsInOneMBB - Returns true if the specified interval is entirely
	/// within a single basic block.
	bool intervalIsInOneMBB(const LiveInterval &li) const;

	/// getLastSplitPoint - Return the last possible insertion point in mbb for
	/// spilling and splitting code. This is the first terminator, or the call
	/// instruction if li is live into a landing pad successor.
	MachineBasicBlock::iterator getLastSplitPoint(const LiveInterval &li,
	MachineBasicBlock *mbb) const;

	/// addKillFlags - Add kill flags to any instruction that kills a virtual
	/// register.
	void addKillFlags();

	private:
	/// computeIntervals - Compute live intervals.
	void computeIntervals();

	/// handleRegisterDef - update intervals for a register def
	/// (calls handlePhysicalRegisterDef and
	/// handleVirtualRegisterDef)
	void handleRegisterDef(MachineBasicBlock *MBB,
	MachineBasicBlock::iterator MI,
	SlotIndex MIIdx,
	MachineOperand& MO, unsigned MOIdx);

	/// isPartialRedef - Return true if the specified def at the specific index
	/// is partially re-defining the specified live interval. A common case of
	/// this is a definition of the sub-register.
	bool isPartialRedef(SlotIndex MIIdx, MachineOperand &MO,
	LiveInterval &interval);

	/// handleVirtualRegisterDef - update intervals for a virtual
	/// register def
	void handleVirtualRegisterDef(MachineBasicBlock *MBB,
	MachineBasicBlock::iterator MI,
	SlotIndex MIIdx, MachineOperand& MO,
	unsigned MOIdx,
	LiveInterval& interval);

	/// handlePhysicalRegisterDef - update intervals for a physical register
	/// def.
	void handlePhysicalRegisterDef(MachineBasicBlock* mbb,
	MachineBasicBlock::iterator mi,
	SlotIndex MIIdx, MachineOperand& MO,
	LiveInterval &interval,
	MachineInstr *CopyMI);

	/// handleLiveInRegister - Create interval for a livein register.
	void handleLiveInRegister(MachineBasicBlock* mbb,
	SlotIndex MIIdx,
	LiveInterval &interval, bool isAlias = false);

	/// getReMatImplicitUse - If the remat definition MI has one (for now, we
	/// only allow one) virtual register operand, then its uses are implicitly
	/// using the register. Returns the virtual register.
	unsigned getReMatImplicitUse(const LiveInterval &li,
	MachineInstr *MI) const;

	/// isValNoAvailableAt - Return true if the val# of the specified interval
	/// which reaches the given instruction also reaches the specified use
	/// index.
	bool isValNoAvailableAt(const LiveInterval &li, MachineInstr *MI,
	SlotIndex UseIdx) const;

	/// isReMaterializable - Returns true if the definition MI of the specified
	/// val# of the specified interval is re-materializable. Also returns true
	/// by reference if the def is a load.
	bool isReMaterializable(const LiveInterval &li, const VNInfo *ValNo,
	MachineInstr *MI,
	const SmallVectorImpl<LiveInterval> SpillIs,
	bool &isLoad);

	/// tryFoldMemoryOperand - Attempts to fold either a spill / restore from
	/// slot / to reg or any rematerialized load into ith operand of specified
	/// MI. If it is successul, MI is updated with the newly created MI and
	/// returns true.
	bool tryFoldMemoryOperand(MachineInstr* &MI, VirtRegMap &vrm,
	MachineInstr *DefMI, SlotIndex InstrIdx,
	SmallVector<unsigned, 2> &Ops,
	bool isSS, int FrameIndex, unsigned Reg);

	/// canFoldMemoryOperand - Return true if the specified load / store
	/// folding is possible.
	bool canFoldMemoryOperand(MachineInstr *MI,
	SmallVector<unsigned, 2> &Ops,
	bool ReMatLoadSS) const;

	/// anyKillInMBBAfterIdx - Returns true if there is a kill of the specified
	/// VNInfo that's after the specified index but is within the basic block.
	bool anyKillInMBBAfterIdx(const LiveInterval &li, const VNInfo *VNI,
	MachineBasicBlock *MBB,
	SlotIndex Idx) const;

	/// hasAllocatableSuperReg - Return true if the specified physical register
	/// has any super register that's allocatable.
	bool hasAllocatableSuperReg(unsigned Reg) const;

	/// SRInfo - Spill / restore info.
	struct SRInfo {
	SlotIndex index;
	unsigned vreg;
	bool canFold;
	SRInfo(SlotIndex i, unsigned vr, bool f)
	: index(i), vreg(vr), canFold(f) {}
	};

	bool alsoFoldARestore(int Id, SlotIndex index, unsigned vr,
	BitVector &RestoreMBBs,
	DenseMap<unsigned,std::vector<SRInfo> >&RestoreIdxes);
	void eraseRestoreInfo(int Id, SlotIndex index, unsigned vr,
	BitVector &RestoreMBBs,
	DenseMap<unsigned,std::vector<SRInfo> >&RestoreIdxes);

	/// handleSpilledImpDefs - Remove IMPLICIT_DEF instructions which are being
	/// spilled and create empty intervals for their uses.
	void handleSpilledImpDefs(const LiveInterval &li, VirtRegMap &vrm,
	const TargetRegisterClass* rc,
	std::vector<LiveInterval*> &NewLIs);

	/// rewriteImplicitOps - Rewrite implicit use operands of MI (i.e. uses of
	/// interval on to-be re-materialized operands of MI) with new register.
	void rewriteImplicitOps(const LiveInterval &li,
	MachineInstr *MI, unsigned NewVReg, VirtRegMap &vrm);

	/// rewriteInstructionForSpills, rewriteInstructionsForSpills - Helper
	/// functions for addIntervalsForSpills to rewrite uses / defs for the given
	/// live range.
	bool rewriteInstructionForSpills(const LiveInterval &li, const VNInfo *VNI,
	bool TrySplit, SlotIndex index, SlotIndex end,
	MachineInstr MI, MachineInstr OrigDefMI, MachineInstr *DefMI,
	unsigned Slot, int LdSlot,
	bool isLoad, bool isLoadSS, bool DefIsReMat, bool CanDelete,
	VirtRegMap &vrm, const TargetRegisterClass* rc,
	SmallVector<int, 4> &ReMatIds, const MachineLoopInfo *loopInfo,
	unsigned &NewVReg, unsigned ImpUse, bool &HasDef, bool &HasUse,
	DenseMap<unsigned,unsigned> &MBBVRegsMap,
	std::vector<LiveInterval*> &NewLIs);
	void rewriteInstructionsForSpills(const LiveInterval &li, bool TrySplit,
	LiveInterval::Ranges::const_iterator &I,
	MachineInstr OrigDefMI, MachineInstr DefMI, unsigned Slot, int LdSlot,
	bool isLoad, bool isLoadSS, bool DefIsReMat, bool CanDelete,
	VirtRegMap &vrm, const TargetRegisterClass* rc,
	SmallVector<int, 4> &ReMatIds, const MachineLoopInfo *loopInfo,
	BitVector &SpillMBBs,
	DenseMap<unsigned,std::vector<SRInfo> > &SpillIdxes,
	BitVector &RestoreMBBs,
	DenseMap<unsigned,std::vector<SRInfo> > &RestoreIdxes,
	DenseMap<unsigned,unsigned> &MBBVRegsMap,
	std::vector<LiveInterval*> &NewLIs);

	static LiveInterval* createInterval(unsigned Reg);

	void printInstrs(raw_ostream &O) const;
	void dumpInstrs() const;
	};
	} // End llvm namespace

	#endif