X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=include%2Fllvm%2FCodeGen%2FLiveInterval.h;h=95760758deca5c67f737f94262e00ad34a4b3419;hb=980bddfb1c26e2e9374d1645f9ae26c44742606f;hp=8e99ee7e29f2e822ae6bcf616cc5921337ba40e3;hpb=a2e6435e483f30e00382a5758f6dcc67e213b57a;p=oota-llvm.git diff --git a/include/llvm/CodeGen/LiveInterval.h b/include/llvm/CodeGen/LiveInterval.h index 8e99ee7e29f..95760758dec 100644 --- a/include/llvm/CodeGen/LiveInterval.h +++ b/include/llvm/CodeGen/LiveInterval.h @@ -21,56 +21,90 @@ #ifndef LLVM_CODEGEN_LIVEINTERVAL_H #define LLVM_CODEGEN_LIVEINTERVAL_H -#include "llvm/ADT/SmallVector.h" +#include "llvm/ADT/IntEqClasses.h" +#include "llvm/CodeGen/SlotIndexes.h" +#include "llvm/Support/AlignOf.h" #include "llvm/Support/Allocator.h" -#include #include +#include namespace llvm { + class CoalescerPair; + class LiveIntervals; class MachineInstr; + class MachineRegisterInfo; class TargetRegisterInfo; - struct LiveInterval; - - /// VNInfo - If the value number definition is undefined (e.g. phi - /// merge point), it contains ~0u,x. If the value number is not in use, it - /// contains ~1u,x to indicate that the value # is not used. - /// def - Instruction # of the definition. - /// - or reg # of the definition if it's a stack slot liveinterval. - /// copy - Copy iff val# is defined by a copy; zero otherwise. - /// hasPHIKill - One or more of the kills are PHI nodes. - /// redefByEC - Re-defined by early clobber somewhere during the live range. - /// kills - Instruction # of the kills. - struct VNInfo { + class raw_ostream; + + /// VNInfo - Value Number Information. + /// This class holds information about a machine level values, including + /// definition and use points. + /// + class VNInfo { + public: + typedef BumpPtrAllocator Allocator; + + /// The ID number of this value. unsigned id; - unsigned def; - MachineInstr *copy; - bool hasPHIKill : 1; - bool redefByEC : 1; - SmallVector kills; - VNInfo() - : id(~1U), def(~1U), copy(0), hasPHIKill(false), redefByEC(false) {} - VNInfo(unsigned i, unsigned d, MachineInstr *c) - : id(i), def(d), copy(c), hasPHIKill(false), redefByEC(false) {} + + /// The index of the defining instruction. + SlotIndex def; + + /// VNInfo constructor. + VNInfo(unsigned i, SlotIndex d) + : id(i), def(d) + { } + + /// VNInfo construtor, copies values from orig, except for the value number. + VNInfo(unsigned i, const VNInfo &orig) + : id(i), def(orig.def) + { } + + /// Copy from the parameter into this VNInfo. + void copyFrom(VNInfo &src) { + def = src.def; + } + + /// Returns true if this value is defined by a PHI instruction (or was, + /// PHI instrucions may have been eliminated). + /// PHI-defs begin at a block boundary, all other defs begin at register or + /// EC slots. + bool isPHIDef() const { return def.isBlock(); } + + /// Returns true if this value is unused. + bool isUnused() const { return !def.isValid(); } + + /// Mark this value as unused. + void markUnused() { def = SlotIndex(); } }; /// LiveRange structure - This represents a simple register range in the /// program, with an inclusive start point and an exclusive end point. /// These ranges are rendered as [start,end). struct LiveRange { - unsigned start; // Start point of the interval (inclusive) - unsigned end; // End point of the interval (exclusive) + SlotIndex start; // Start point of the interval (inclusive) + SlotIndex end; // End point of the interval (exclusive) VNInfo *valno; // identifier for the value contained in this interval. - LiveRange(unsigned S, unsigned E, VNInfo *V) : start(S), end(E), valno(V) { + LiveRange(SlotIndex S, SlotIndex E, VNInfo *V) + : start(S), end(E), valno(V) { + assert(S < E && "Cannot create empty or backwards range"); } /// contains - Return true if the index is covered by this range. /// - bool contains(unsigned I) const { + bool contains(SlotIndex I) const { return start <= I && I < end; } + /// containsRange - Return true if the given range, [S, E), is covered by + /// this range. + bool containsRange(SlotIndex S, SlotIndex E) const { + assert((S < E) && "Backwards interval?"); + return (start <= S && S < end) && (start < E && E <= end); + } + bool operator<(const LiveRange &LR) const { return start < LR.start || (start == LR.start && end < LR.end); } @@ -79,44 +113,49 @@ namespace llvm { } void dump() const; - void print(std::ostream &os) const; - void print(std::ostream *os) const { if (os) print(*os); } - - private: - LiveRange(); // DO NOT IMPLEMENT + void print(raw_ostream &os) const; }; - std::ostream& operator<<(std::ostream& os, const LiveRange &LR); + template <> struct isPodLike { static const bool value = true; }; + + raw_ostream& operator<<(raw_ostream& os, const LiveRange &LR); - inline bool operator<(unsigned V, const LiveRange &LR) { + inline bool operator<(SlotIndex V, const LiveRange &LR) { return V < LR.start; } - inline bool operator<(const LiveRange &LR, unsigned V) { + inline bool operator<(const LiveRange &LR, SlotIndex V) { return LR.start < V; } /// LiveInterval - This class represents some number of live ranges for a /// register or value. This class also contains a bit of register allocator /// state. - struct LiveInterval { + class LiveInterval { + public: + typedef SmallVector Ranges; typedef SmallVector VNInfoList; - unsigned reg; // the register or stack slot of this interval - // if the top bits is set, it represents a stack slot. + const unsigned reg; // the register or stack slot of this interval. float weight; // weight of this interval - unsigned short preference; // preferred register for this interval Ranges ranges; // the ranges in which this register is live VNInfoList valnos; // value#'s - public: - LiveInterval(unsigned Reg, float Weight, bool IsSS = false) - : reg(Reg), weight(Weight), preference(0) { - if (IsSS) - reg = reg | (1U << (sizeof(unsigned)*8-1)); - } + struct InstrSlots { + enum { + LOAD = 0, + USE = 1, + DEF = 2, + STORE = 3, + NUM = 4 + }; + + }; + + LiveInterval(unsigned Reg, float Weight) + : reg(Reg), weight(Weight) {} typedef Ranges::iterator iterator; iterator begin() { return ranges.begin(); } @@ -137,36 +176,32 @@ namespace llvm { /// advanceTo - Advance the specified iterator to point to the LiveRange /// containing the specified position, or end() if the position is past the /// end of the interval. If no LiveRange contains this position, but the - /// position is in a hole, this method returns an iterator pointing the the + /// position is in a hole, this method returns an iterator pointing to the /// LiveRange immediately after the hole. - iterator advanceTo(iterator I, unsigned Pos) { - if (Pos >= endNumber()) + iterator advanceTo(iterator I, SlotIndex Pos) { + assert(I != end()); + if (Pos >= endIndex()) return end(); while (I->end <= Pos) ++I; return I; } - - void clear() { - while (!valnos.empty()) { - VNInfo *VNI = valnos.back(); - valnos.pop_back(); - VNI->~VNInfo(); - } - - ranges.clear(); - } - /// isStackSlot - Return true if this is a stack slot interval. + /// find - Return an iterator pointing to the first range that ends after + /// Pos, or end(). This is the same as advanceTo(begin(), Pos), but faster + /// when searching large intervals. /// - bool isStackSlot() const { - return reg & (1U << (sizeof(unsigned)*8-1)); + /// If Pos is contained in a LiveRange, that range is returned. + /// If Pos is in a hole, the following LiveRange is returned. + /// If Pos is beyond endIndex, end() is returned. + iterator find(SlotIndex Pos); + + const_iterator find(SlotIndex Pos) const { + return const_cast(this)->find(Pos); } - /// getStackSlotIndex - Return stack slot index if this is a stack slot - /// interval. - int getStackSlotIndex() const { - assert(isStackSlot() && "Interval is not a stack slot interval!"); - return reg & ~(1U << (sizeof(unsigned)*8-1)); + void clear() { + valnos.clear(); + ranges.clear(); } bool hasAtLeastOneValue() const { return !valnos.empty(); } @@ -174,7 +209,7 @@ namespace llvm { bool containsOneValue() const { return valnos.size() == 1; } unsigned getNumValNums() const { return (unsigned)valnos.size(); } - + /// getValNumInfo - Returns pointer to the specified val#. /// inline VNInfo *getValNumInfo(unsigned ValNo) { @@ -183,128 +218,46 @@ namespace llvm { inline const VNInfo *getValNumInfo(unsigned ValNo) const { return valnos[ValNo]; } - - /// copyValNumInfo - Copy the value number info for one value number to - /// another. - void copyValNumInfo(VNInfo *DstValNo, const VNInfo *SrcValNo) { - DstValNo->def = SrcValNo->def; - DstValNo->copy = SrcValNo->copy; - DstValNo->hasPHIKill = SrcValNo->hasPHIKill; - DstValNo->redefByEC = SrcValNo->redefByEC; - DstValNo->kills = SrcValNo->kills; + + /// containsValue - Returns true if VNI belongs to this interval. + bool containsValue(const VNInfo *VNI) const { + return VNI && VNI->id < getNumValNums() && VNI == getValNumInfo(VNI->id); } /// getNextValue - Create a new value number and return it. MIIdx specifies /// the instruction that defines the value number. - VNInfo *getNextValue(unsigned MIIdx, MachineInstr *CopyMI, - BumpPtrAllocator &VNInfoAllocator) { -#ifdef __GNUC__ - unsigned Alignment = (unsigned)__alignof__(VNInfo); -#else - // FIXME: ugly. - unsigned Alignment = 8; -#endif + VNInfo *getNextValue(SlotIndex def, VNInfo::Allocator &VNInfoAllocator) { VNInfo *VNI = - static_cast(VNInfoAllocator.Allocate((unsigned)sizeof(VNInfo), - Alignment)); - new (VNI) VNInfo((unsigned)valnos.size(), MIIdx, CopyMI); + new (VNInfoAllocator) VNInfo((unsigned)valnos.size(), def); valnos.push_back(VNI); return VNI; } - /// getUnknownValNo - Find a value# for unknown values, if there isn't one - /// create a new one. - VNInfo *getUnknownValNo(BumpPtrAllocator &VNInfoAllocator); - - /// addKill - Add a kill instruction index to the specified value - /// number. - static void addKill(VNInfo *VNI, unsigned KillIdx) { - SmallVector &kills = VNI->kills; - if (kills.empty()) { - kills.push_back(KillIdx); - } else { - SmallVector::iterator - I = std::lower_bound(kills.begin(), kills.end(), KillIdx); - kills.insert(I, KillIdx); - } - } + /// createDeadDef - Make sure the interval has a value defined at Def. + /// If one already exists, return it. Otherwise allocate a new value and + /// add liveness for a dead def. + VNInfo *createDeadDef(SlotIndex Def, VNInfo::Allocator &VNInfoAllocator); - /// addKills - Add a number of kills into the VNInfo kill vector. If this - /// interval is live at a kill point, then the kill is not added. - void addKills(VNInfo *VNI, const SmallVector &kills) { - for (unsigned i = 0, e = static_cast(kills.size()); - i != e; ++i) { - unsigned KillIdx = kills[i]; - if (!liveBeforeAndAt(KillIdx)) { - SmallVector::iterator - I = std::lower_bound(VNI->kills.begin(), VNI->kills.end(), KillIdx); - VNI->kills.insert(I, KillIdx); - } - } + /// Create a copy of the given value. The new value will be identical except + /// for the Value number. + VNInfo *createValueCopy(const VNInfo *orig, + VNInfo::Allocator &VNInfoAllocator) { + VNInfo *VNI = + new (VNInfoAllocator) VNInfo((unsigned)valnos.size(), *orig); + valnos.push_back(VNI); + return VNI; } - /// removeKill - Remove the specified kill from the list of kills of - /// the specified val#. - static bool removeKill(VNInfo *VNI, unsigned KillIdx) { - SmallVector &kills = VNI->kills; - SmallVector::iterator - I = std::lower_bound(kills.begin(), kills.end(), KillIdx); - if (I != kills.end() && *I == KillIdx) { - kills.erase(I); - return true; - } - return false; - } - - /// removeKills - Remove all the kills in specified range - /// [Start, End] of the specified val#. - static void removeKills(VNInfo *VNI, unsigned Start, unsigned End) { - SmallVector &kills = VNI->kills; - SmallVector::iterator - I = std::lower_bound(kills.begin(), kills.end(), Start); - SmallVector::iterator - E = std::upper_bound(kills.begin(), kills.end(), End); - kills.erase(I, E); - } - - /// isKill - Return true if the specified index is a kill of the - /// specified val#. - static bool isKill(const VNInfo *VNI, unsigned KillIdx) { - const SmallVector &kills = VNI->kills; - SmallVector::const_iterator - I = std::lower_bound(kills.begin(), kills.end(), KillIdx); - return I != kills.end() && *I == KillIdx; - } - - /// isOnlyLROfValNo - Return true if the specified live range is the only - /// one defined by the its val#. - bool isOnlyLROfValNo( const LiveRange *LR) { - for (const_iterator I = begin(), E = end(); I != E; ++I) { - const LiveRange *Tmp = I; - if (Tmp != LR && Tmp->valno == LR->valno) - return false; - } - return true; - } - + /// RenumberValues - Renumber all values in order of appearance and remove + /// unused values. + void RenumberValues(LiveIntervals &lis); + /// MergeValueNumberInto - This method is called when two value nubmers /// are found to be equivalent. This eliminates V1, replacing all /// LiveRanges with the V1 value number with the V2 value number. This can /// cause merging of V1/V2 values numbers and compaction of the value space. VNInfo* MergeValueNumberInto(VNInfo *V1, VNInfo *V2); - /// MergeInClobberRanges - For any live ranges that are not defined in the - /// current interval, but are defined in the Clobbers interval, mark them - /// used with an unknown definition value. Caller must pass in reference to - /// VNInfoAllocator since it will create a new val#. - void MergeInClobberRanges(const LiveInterval &Clobbers, - BumpPtrAllocator &VNInfoAllocator); - - /// MergeInClobberRange - Same as MergeInClobberRanges except it merge in a - /// single LiveRange only. - void MergeInClobberRange(unsigned Start, unsigned End, - BumpPtrAllocator &VNInfoAllocator); - /// MergeValueInAsValue - Merge all of the live ranges of a specific val# /// in RHS into this live interval as the specified value number. /// The LiveRanges in RHS are allowed to overlap with LiveRanges in the @@ -320,64 +273,98 @@ namespace llvm { void MergeValueInAsValue(const LiveInterval &RHS, const VNInfo *RHSValNo, VNInfo *LHSValNo); - /// Copy - Copy the specified live interval. This copies all the fields - /// except for the register of the interval. - void Copy(const LiveInterval &RHS, BumpPtrAllocator &VNInfoAllocator); - bool empty() const { return ranges.empty(); } - /// beginNumber - Return the lowest numbered slot covered by interval. - unsigned beginNumber() const { - if (empty()) - return 0; + /// beginIndex - Return the lowest numbered slot covered by interval. + SlotIndex beginIndex() const { + assert(!empty() && "Call to beginIndex() on empty interval."); return ranges.front().start; } /// endNumber - return the maximum point of the interval of the whole, /// exclusive. - unsigned endNumber() const { - if (empty()) - return 0; + SlotIndex endIndex() const { + assert(!empty() && "Call to endIndex() on empty interval."); return ranges.back().end; } - bool expiredAt(unsigned index) const { - return index >= endNumber(); + bool expiredAt(SlotIndex index) const { + return index >= endIndex(); } - bool liveAt(unsigned index) const; + bool liveAt(SlotIndex index) const { + const_iterator r = find(index); + return r != end() && r->start <= index; + } - // liveBeforeAndAt - Check if the interval is live at the index and the - // index just before it. If index is liveAt, check if it starts a new live - // range.If it does, then check if the previous live range ends at index-1. - bool liveBeforeAndAt(unsigned index) const; + /// killedAt - Return true if a live range ends at index. Note that the kill + /// point is not contained in the half-open live range. It is usually the + /// getDefIndex() slot following its last use. + bool killedAt(SlotIndex index) const { + const_iterator r = find(index.getRegSlot(true)); + return r != end() && r->end == index; + } /// getLiveRangeContaining - Return the live range that contains the /// specified index, or null if there is none. - const LiveRange *getLiveRangeContaining(unsigned Idx) const { + const LiveRange *getLiveRangeContaining(SlotIndex Idx) const { const_iterator I = FindLiveRangeContaining(Idx); return I == end() ? 0 : &*I; } - /// FindLiveRangeContaining - Return an iterator to the live range that - /// contains the specified index, or end() if there is none. - const_iterator FindLiveRangeContaining(unsigned Idx) const; + /// getLiveRangeContaining - Return the live range that contains the + /// specified index, or null if there is none. + LiveRange *getLiveRangeContaining(SlotIndex Idx) { + iterator I = FindLiveRangeContaining(Idx); + return I == end() ? 0 : &*I; + } + + /// getVNInfoAt - Return the VNInfo that is live at Idx, or NULL. + VNInfo *getVNInfoAt(SlotIndex Idx) const { + const_iterator I = FindLiveRangeContaining(Idx); + return I == end() ? 0 : I->valno; + } + + /// getVNInfoBefore - Return the VNInfo that is live up to but not + /// necessarilly including Idx, or NULL. Use this to find the reaching def + /// used by an instruction at this SlotIndex position. + VNInfo *getVNInfoBefore(SlotIndex Idx) const { + const_iterator I = FindLiveRangeContaining(Idx.getPrevSlot()); + return I == end() ? 0 : I->valno; + } /// FindLiveRangeContaining - Return an iterator to the live range that /// contains the specified index, or end() if there is none. - iterator FindLiveRangeContaining(unsigned Idx); + iterator FindLiveRangeContaining(SlotIndex Idx) { + iterator I = find(Idx); + return I != end() && I->start <= Idx ? I : end(); + } + + const_iterator FindLiveRangeContaining(SlotIndex Idx) const { + const_iterator I = find(Idx); + return I != end() && I->start <= Idx ? I : end(); + } - /// findDefinedVNInfo - Find the VNInfo that's defined at the specified - /// index (register interval) or defined by the specified register (stack - /// inteval). - VNInfo *findDefinedVNInfo(unsigned DefIdxOrReg) const; - /// overlaps - Return true if the intersection of the two live intervals is /// not empty. bool overlaps(const LiveInterval& other) const { + if (other.empty()) + return false; return overlapsFrom(other, other.begin()); } + /// overlaps - Return true if the two intervals have overlapping segments + /// that are not coalescable according to CP. + /// + /// Overlapping segments where one interval is defined by a coalescable + /// copy are allowed. + bool overlaps(const LiveInterval &Other, const CoalescerPair &CP, + const SlotIndexes&) const; + + /// overlaps - Return true if the live interval overlaps a range specified + /// by [Start, End). + bool overlaps(SlotIndex Start, SlotIndex End) const; + /// overlapsFrom - Return true if the intersection of the two live intervals /// is not empty. The specified iterator is a hint that we can begin /// scanning the Other interval starting at I. @@ -390,20 +377,31 @@ namespace llvm { addRangeFrom(LR, ranges.begin()); } + /// extendInBlock - If this interval is live before Kill in the basic block + /// that starts at StartIdx, extend it to be live up to Kill, and return + /// the value. If there is no live range before Kill, return NULL. + VNInfo *extendInBlock(SlotIndex StartIdx, SlotIndex Kill); + /// join - Join two live intervals (this, and other) together. This applies /// mappings to the value numbers in the LHS/RHS intervals as specified. If /// the intervals are not joinable, this aborts. - void join(LiveInterval &Other, const int *ValNoAssignments, + void join(LiveInterval &Other, + const int *ValNoAssignments, const int *RHSValNoAssignments, - SmallVector &NewVNInfo); + SmallVector &NewVNInfo, + MachineRegisterInfo *MRI); /// isInOneLiveRange - Return true if the range specified is entirely in the /// a single LiveRange of the live interval. - bool isInOneLiveRange(unsigned Start, unsigned End); + bool isInOneLiveRange(SlotIndex Start, SlotIndex End) const { + const_iterator r = find(Start); + return r != end() && r->containsRange(Start, End); + } /// removeRange - Remove the specified range from this interval. Note that /// the range must be a single LiveRange in its entirety. - void removeRange(unsigned Start, unsigned End, bool RemoveDeadValNo = false); + void removeRange(SlotIndex Start, SlotIndex End, + bool RemoveDeadValNo = false); void removeRange(LiveRange LR, bool RemoveDeadValNo = false) { removeRange(LR.start, LR.end, RemoveDeadValNo); @@ -417,27 +415,197 @@ namespace llvm { /// unsigned getSize() const; - bool operator<(const LiveInterval& other) const { - return beginNumber() < other.beginNumber(); + /// Returns true if the live interval is zero length, i.e. no live ranges + /// span instructions. It doesn't pay to spill such an interval. + bool isZeroLength(SlotIndexes *Indexes) const { + for (const_iterator i = begin(), e = end(); i != e; ++i) + if (Indexes->getNextNonNullIndex(i->start).getBaseIndex() < + i->end.getBaseIndex()) + return false; + return true; + } + + /// isSpillable - Can this interval be spilled? + bool isSpillable() const { + return weight != HUGE_VALF; } - void print(std::ostream &OS, const TargetRegisterInfo *TRI = 0) const; - void print(std::ostream *OS, const TargetRegisterInfo *TRI = 0) const { - if (OS) print(*OS, TRI); + /// markNotSpillable - Mark interval as not spillable + void markNotSpillable() { + weight = HUGE_VALF; } + + bool operator<(const LiveInterval& other) const { + const SlotIndex &thisIndex = beginIndex(); + const SlotIndex &otherIndex = other.beginIndex(); + return (thisIndex < otherIndex || + (thisIndex == otherIndex && reg < other.reg)); + } + + void print(raw_ostream &OS) const; void dump() const; + /// \brief Walk the interval and assert if any invariants fail to hold. + /// + /// Note that this is a no-op when asserts are disabled. +#ifdef NDEBUG + void verify() const {} +#else + void verify() const; +#endif + private: + Ranges::iterator addRangeFrom(LiveRange LR, Ranges::iterator From); - void extendIntervalEndTo(Ranges::iterator I, unsigned NewEnd); - Ranges::iterator extendIntervalStartTo(Ranges::iterator I, unsigned NewStr); - LiveInterval& operator=(const LiveInterval& rhs); // DO NOT IMPLEMENT + void extendIntervalEndTo(Ranges::iterator I, SlotIndex NewEnd); + Ranges::iterator extendIntervalStartTo(Ranges::iterator I, SlotIndex NewStr); + void markValNoForDeletion(VNInfo *V); + void mergeIntervalRanges(const LiveInterval &RHS, + VNInfo *LHSValNo = 0, + const VNInfo *RHSValNo = 0); + + LiveInterval& operator=(const LiveInterval& rhs) LLVM_DELETED_FUNCTION; + }; - inline std::ostream &operator<<(std::ostream &OS, const LiveInterval &LI) { + inline raw_ostream &operator<<(raw_ostream &OS, const LiveInterval &LI) { LI.print(OS); return OS; } -} + /// LiveRangeQuery - Query information about a live range around a given + /// instruction. This class hides the implementation details of live ranges, + /// and it should be used as the primary interface for examining live ranges + /// around instructions. + /// + class LiveRangeQuery { + VNInfo *EarlyVal; + VNInfo *LateVal; + SlotIndex EndPoint; + bool Kill; + + public: + /// Create a LiveRangeQuery for the given live range and instruction index. + /// The sub-instruction slot of Idx doesn't matter, only the instruction it + /// refers to is considered. + LiveRangeQuery(const LiveInterval &LI, SlotIndex Idx) + : EarlyVal(0), LateVal(0), Kill(false) { + // Find the segment that enters the instruction. + LiveInterval::const_iterator I = LI.find(Idx.getBaseIndex()); + LiveInterval::const_iterator E = LI.end(); + if (I == E) + return; + // Is this an instruction live-in segment? + // If Idx is the start index of a basic block, include live-in segments + // that start at Idx.getBaseIndex(). + if (I->start <= Idx.getBaseIndex()) { + EarlyVal = I->valno; + EndPoint = I->end; + // Move to the potentially live-out segment. + if (SlotIndex::isSameInstr(Idx, I->end)) { + Kill = true; + if (++I == E) + return; + } + // Special case: A PHIDef value can have its def in the middle of a + // segment if the value happens to be live out of the layout + // predecessor. + // Such a value is not live-in. + if (EarlyVal->def == Idx.getBaseIndex()) + EarlyVal = 0; + } + // I now points to the segment that may be live-through, or defined by + // this instr. Ignore segments starting after the current instr. + if (SlotIndex::isEarlierInstr(Idx, I->start)) + return; + LateVal = I->valno; + EndPoint = I->end; + } + + /// Return the value that is live-in to the instruction. This is the value + /// that will be read by the instruction's use operands. Return NULL if no + /// value is live-in. + VNInfo *valueIn() const { + return EarlyVal; + } + + /// Return true if the live-in value is killed by this instruction. This + /// means that either the live range ends at the instruction, or it changes + /// value. + bool isKill() const { + return Kill; + } + + /// Return true if this instruction has a dead def. + bool isDeadDef() const { + return EndPoint.isDead(); + } + + /// Return the value leaving the instruction, if any. This can be a + /// live-through value, or a live def. A dead def returns NULL. + VNInfo *valueOut() const { + return isDeadDef() ? 0 : LateVal; + } + + /// Return the value defined by this instruction, if any. This includes + /// dead defs, it is the value created by the instruction's def operands. + VNInfo *valueDefined() const { + return EarlyVal == LateVal ? 0 : LateVal; + } + + /// Return the end point of the last live range segment to interact with + /// the instruction, if any. + /// + /// The end point is an invalid SlotIndex only if the live range doesn't + /// intersect the instruction at all. + /// + /// The end point may be at or past the end of the instruction's basic + /// block. That means the value was live out of the block. + SlotIndex endPoint() const { + return EndPoint; + } + }; + + /// ConnectedVNInfoEqClasses - Helper class that can divide VNInfos in a + /// LiveInterval into equivalence clases of connected components. A + /// LiveInterval that has multiple connected components can be broken into + /// multiple LiveIntervals. + /// + /// Given a LiveInterval that may have multiple connected components, run: + /// + /// unsigned numComps = ConEQ.Classify(LI); + /// if (numComps > 1) { + /// // allocate numComps-1 new LiveIntervals into LIS[1..] + /// ConEQ.Distribute(LIS); + /// } + + class ConnectedVNInfoEqClasses { + LiveIntervals &LIS; + IntEqClasses EqClass; + + // Note that values a and b are connected. + void Connect(unsigned a, unsigned b); + + unsigned Renumber(); + + public: + explicit ConnectedVNInfoEqClasses(LiveIntervals &lis) : LIS(lis) {} + + /// Classify - Classify the values in LI into connected components. + /// Return the number of connected components. + unsigned Classify(const LiveInterval *LI); + + /// getEqClass - Classify creates equivalence classes numbered 0..N. Return + /// the equivalence class assigned the VNI. + unsigned getEqClass(const VNInfo *VNI) const { return EqClass[VNI->id]; } + + /// Distribute - Distribute values in LIV[0] into a separate LiveInterval + /// for each connected component. LIV must have a LiveInterval for each + /// connected component. The LiveIntervals in Liv[1..] must be empty. + /// Instructions using LIV[0] are rewritten. + void Distribute(LiveInterval *LIV[], MachineRegisterInfo &MRI); + + }; + +} #endif