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Diffstat (limited to 'contrib/llvm/lib/CodeGen/PreAllocSplitting.cpp')
| -rw-r--r-- | contrib/llvm/lib/CodeGen/PreAllocSplitting.cpp | 1430 |
1 files changed, 0 insertions, 1430 deletions
diff --git a/contrib/llvm/lib/CodeGen/PreAllocSplitting.cpp b/contrib/llvm/lib/CodeGen/PreAllocSplitting.cpp deleted file mode 100644 index d6e31da..0000000 --- a/contrib/llvm/lib/CodeGen/PreAllocSplitting.cpp +++ /dev/null @@ -1,1430 +0,0 @@ -//===-- PreAllocSplitting.cpp - Pre-allocation Interval Spltting Pass. ----===// -// -// 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 machine instruction level pre-register allocation -// live interval splitting pass. It finds live interval barriers, i.e. -// instructions which will kill all physical registers in certain register -// classes, and split all live intervals which cross the barrier. -// -//===----------------------------------------------------------------------===// - -#define DEBUG_TYPE "pre-alloc-split" -#include "VirtRegMap.h" -#include "llvm/CodeGen/CalcSpillWeights.h" -#include "llvm/CodeGen/LiveIntervalAnalysis.h" -#include "llvm/CodeGen/LiveStackAnalysis.h" -#include "llvm/CodeGen/MachineDominators.h" -#include "llvm/CodeGen/MachineFrameInfo.h" -#include "llvm/CodeGen/MachineFunctionPass.h" -#include "llvm/CodeGen/MachineLoopInfo.h" -#include "llvm/CodeGen/MachineRegisterInfo.h" -#include "llvm/CodeGen/Passes.h" -#include "llvm/CodeGen/RegisterCoalescer.h" -#include "llvm/Target/TargetInstrInfo.h" -#include "llvm/Target/TargetMachine.h" -#include "llvm/Target/TargetOptions.h" -#include "llvm/Target/TargetRegisterInfo.h" -#include "llvm/Support/CommandLine.h" -#include "llvm/Support/Debug.h" -#include "llvm/Support/ErrorHandling.h" -#include "llvm/ADT/DenseMap.h" -#include "llvm/ADT/DepthFirstIterator.h" -#include "llvm/ADT/SmallPtrSet.h" -#include "llvm/ADT/Statistic.h" -using namespace llvm; - -static cl::opt<int> PreSplitLimit("pre-split-limit", cl::init(-1), cl::Hidden); -static cl::opt<int> DeadSplitLimit("dead-split-limit", cl::init(-1), - cl::Hidden); -static cl::opt<int> RestoreFoldLimit("restore-fold-limit", cl::init(-1), - cl::Hidden); - -STATISTIC(NumSplits, "Number of intervals split"); -STATISTIC(NumRemats, "Number of intervals split by rematerialization"); -STATISTIC(NumFolds, "Number of intervals split with spill folding"); -STATISTIC(NumRestoreFolds, "Number of intervals split with restore folding"); -STATISTIC(NumRenumbers, "Number of intervals renumbered into new registers"); -STATISTIC(NumDeadSpills, "Number of dead spills removed"); - -namespace { - class PreAllocSplitting : public MachineFunctionPass { - MachineFunction *CurrMF; - const TargetMachine *TM; - const TargetInstrInfo *TII; - const TargetRegisterInfo* TRI; - MachineFrameInfo *MFI; - MachineRegisterInfo *MRI; - SlotIndexes *SIs; - LiveIntervals *LIs; - LiveStacks *LSs; - VirtRegMap *VRM; - - // Barrier - Current barrier being processed. - MachineInstr *Barrier; - - // BarrierMBB - Basic block where the barrier resides in. - MachineBasicBlock *BarrierMBB; - - // Barrier - Current barrier index. - SlotIndex BarrierIdx; - - // CurrLI - Current live interval being split. - LiveInterval *CurrLI; - - // CurrSLI - Current stack slot live interval. - LiveInterval *CurrSLI; - - // CurrSValNo - Current val# for the stack slot live interval. - VNInfo *CurrSValNo; - - // IntervalSSMap - A map from live interval to spill slots. - DenseMap<unsigned, int> IntervalSSMap; - - // Def2SpillMap - A map from a def instruction index to spill index. - DenseMap<SlotIndex, SlotIndex> Def2SpillMap; - - public: - static char ID; - PreAllocSplitting() : MachineFunctionPass(ID) { - initializePreAllocSplittingPass(*PassRegistry::getPassRegistry()); - } - - virtual bool runOnMachineFunction(MachineFunction &MF); - - virtual void getAnalysisUsage(AnalysisUsage &AU) const { - AU.setPreservesCFG(); - AU.addRequired<SlotIndexes>(); - AU.addPreserved<SlotIndexes>(); - AU.addRequired<LiveIntervals>(); - AU.addPreserved<LiveIntervals>(); - AU.addRequired<LiveStacks>(); - AU.addPreserved<LiveStacks>(); - AU.addPreserved<RegisterCoalescer>(); - AU.addPreserved<CalculateSpillWeights>(); - AU.addPreservedID(StrongPHIEliminationID); - AU.addPreservedID(PHIEliminationID); - AU.addRequired<MachineDominatorTree>(); - AU.addRequired<MachineLoopInfo>(); - AU.addRequired<VirtRegMap>(); - AU.addPreserved<MachineDominatorTree>(); - AU.addPreserved<MachineLoopInfo>(); - AU.addPreserved<VirtRegMap>(); - MachineFunctionPass::getAnalysisUsage(AU); - } - - virtual void releaseMemory() { - IntervalSSMap.clear(); - Def2SpillMap.clear(); - } - - virtual const char *getPassName() const { - return "Pre-Register Allocaton Live Interval Splitting"; - } - - /// print - Implement the dump method. - virtual void print(raw_ostream &O, const Module* M = 0) const { - LIs->print(O, M); - } - - - private: - - MachineBasicBlock::iterator - findSpillPoint(MachineBasicBlock*, MachineInstr*, MachineInstr*, - SmallPtrSet<MachineInstr*, 4>&); - - MachineBasicBlock::iterator - findRestorePoint(MachineBasicBlock*, MachineInstr*, SlotIndex, - SmallPtrSet<MachineInstr*, 4>&); - - int CreateSpillStackSlot(unsigned, const TargetRegisterClass *); - - bool IsAvailableInStack(MachineBasicBlock*, unsigned, - SlotIndex, SlotIndex, - SlotIndex&, int&) const; - - void UpdateSpillSlotInterval(VNInfo*, SlotIndex, SlotIndex); - - bool SplitRegLiveInterval(LiveInterval*); - - bool SplitRegLiveIntervals(const TargetRegisterClass **, - SmallPtrSet<LiveInterval*, 8>&); - - bool createsNewJoin(LiveRange* LR, MachineBasicBlock* DefMBB, - MachineBasicBlock* BarrierMBB); - bool Rematerialize(unsigned vreg, VNInfo* ValNo, - MachineInstr* DefMI, - MachineBasicBlock::iterator RestorePt, - SmallPtrSet<MachineInstr*, 4>& RefsInMBB); - MachineInstr* FoldSpill(unsigned vreg, const TargetRegisterClass* RC, - MachineInstr* DefMI, - MachineInstr* Barrier, - MachineBasicBlock* MBB, - int& SS, - SmallPtrSet<MachineInstr*, 4>& RefsInMBB); - MachineInstr* FoldRestore(unsigned vreg, - const TargetRegisterClass* RC, - MachineInstr* Barrier, - MachineBasicBlock* MBB, - int SS, - SmallPtrSet<MachineInstr*, 4>& RefsInMBB); - void RenumberValno(VNInfo* VN); - void ReconstructLiveInterval(LiveInterval* LI); - bool removeDeadSpills(SmallPtrSet<LiveInterval*, 8>& split); - unsigned getNumberOfNonSpills(SmallPtrSet<MachineInstr*, 4>& MIs, - unsigned Reg, int FrameIndex, bool& TwoAddr); - VNInfo* PerformPHIConstruction(MachineBasicBlock::iterator Use, - MachineBasicBlock* MBB, LiveInterval* LI, - SmallPtrSet<MachineInstr*, 4>& Visited, - DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 2> >& Defs, - DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 2> >& Uses, - DenseMap<MachineInstr*, VNInfo*>& NewVNs, - DenseMap<MachineBasicBlock*, VNInfo*>& LiveOut, - DenseMap<MachineBasicBlock*, VNInfo*>& Phis, - bool IsTopLevel, bool IsIntraBlock); - VNInfo* PerformPHIConstructionFallBack(MachineBasicBlock::iterator Use, - MachineBasicBlock* MBB, LiveInterval* LI, - SmallPtrSet<MachineInstr*, 4>& Visited, - DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 2> >& Defs, - DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 2> >& Uses, - DenseMap<MachineInstr*, VNInfo*>& NewVNs, - DenseMap<MachineBasicBlock*, VNInfo*>& LiveOut, - DenseMap<MachineBasicBlock*, VNInfo*>& Phis, - bool IsTopLevel, bool IsIntraBlock); -}; -} // end anonymous namespace - -char PreAllocSplitting::ID = 0; - -INITIALIZE_PASS_BEGIN(PreAllocSplitting, "pre-alloc-splitting", - "Pre-Register Allocation Live Interval Splitting", - false, false) -INITIALIZE_PASS_DEPENDENCY(SlotIndexes) -INITIALIZE_PASS_DEPENDENCY(LiveIntervals) -INITIALIZE_PASS_DEPENDENCY(LiveStacks) -INITIALIZE_PASS_DEPENDENCY(MachineDominatorTree) -INITIALIZE_PASS_DEPENDENCY(MachineLoopInfo) -INITIALIZE_PASS_DEPENDENCY(VirtRegMap) -INITIALIZE_PASS_END(PreAllocSplitting, "pre-alloc-splitting", - "Pre-Register Allocation Live Interval Splitting", - false, false) - -char &llvm::PreAllocSplittingID = PreAllocSplitting::ID; - -/// findSpillPoint - Find a gap as far away from the given MI that's suitable -/// for spilling the current live interval. The index must be before any -/// defs and uses of the live interval register in the mbb. Return begin() if -/// none is found. -MachineBasicBlock::iterator -PreAllocSplitting::findSpillPoint(MachineBasicBlock *MBB, MachineInstr *MI, - MachineInstr *DefMI, - SmallPtrSet<MachineInstr*, 4> &RefsInMBB) { - MachineBasicBlock::iterator Pt = MBB->begin(); - - MachineBasicBlock::iterator MII = MI; - MachineBasicBlock::iterator EndPt = DefMI - ? MachineBasicBlock::iterator(DefMI) : MBB->begin(); - - while (MII != EndPt && !RefsInMBB.count(MII) && - MII->getOpcode() != TRI->getCallFrameSetupOpcode()) - --MII; - if (MII == EndPt || RefsInMBB.count(MII)) return Pt; - - while (MII != EndPt && !RefsInMBB.count(MII)) { - // We can't insert the spill between the barrier (a call), and its - // corresponding call frame setup. - if (MII->getOpcode() == TRI->getCallFrameDestroyOpcode()) { - while (MII->getOpcode() != TRI->getCallFrameSetupOpcode()) { - --MII; - if (MII == EndPt) { - return Pt; - } - } - continue; - } else { - Pt = MII; - } - - if (RefsInMBB.count(MII)) - return Pt; - - - --MII; - } - - return Pt; -} - -/// findRestorePoint - Find a gap in the instruction index map that's suitable -/// for restoring the current live interval value. The index must be before any -/// uses of the live interval register in the mbb. Return end() if none is -/// found. -MachineBasicBlock::iterator -PreAllocSplitting::findRestorePoint(MachineBasicBlock *MBB, MachineInstr *MI, - SlotIndex LastIdx, - SmallPtrSet<MachineInstr*, 4> &RefsInMBB) { - // FIXME: Allow spill to be inserted to the beginning of the mbb. Update mbb - // begin index accordingly. - MachineBasicBlock::iterator Pt = MBB->end(); - MachineBasicBlock::iterator EndPt = MBB->getFirstTerminator(); - - // We start at the call, so walk forward until we find the call frame teardown - // since we can't insert restores before that. Bail if we encounter a use - // during this time. - MachineBasicBlock::iterator MII = MI; - if (MII == EndPt) return Pt; - - while (MII != EndPt && !RefsInMBB.count(MII) && - MII->getOpcode() != TRI->getCallFrameDestroyOpcode()) - ++MII; - if (MII == EndPt || RefsInMBB.count(MII)) return Pt; - ++MII; - - // FIXME: Limit the number of instructions to examine to reduce - // compile time? - while (MII != EndPt) { - SlotIndex Index = LIs->getInstructionIndex(MII); - if (Index > LastIdx) - break; - - // We can't insert a restore between the barrier (a call) and its - // corresponding call frame teardown. - if (MII->getOpcode() == TRI->getCallFrameSetupOpcode()) { - do { - if (MII == EndPt || RefsInMBB.count(MII)) return Pt; - ++MII; - } while (MII->getOpcode() != TRI->getCallFrameDestroyOpcode()); - } else { - Pt = MII; - } - - if (RefsInMBB.count(MII)) - return Pt; - - ++MII; - } - - return Pt; -} - -/// CreateSpillStackSlot - Create a stack slot for the live interval being -/// split. If the live interval was previously split, just reuse the same -/// slot. -int PreAllocSplitting::CreateSpillStackSlot(unsigned Reg, - const TargetRegisterClass *RC) { - int SS; - DenseMap<unsigned, int>::iterator I = IntervalSSMap.find(Reg); - if (I != IntervalSSMap.end()) { - SS = I->second; - } else { - SS = MFI->CreateSpillStackObject(RC->getSize(), RC->getAlignment()); - IntervalSSMap[Reg] = SS; - } - - // Create live interval for stack slot. - CurrSLI = &LSs->getOrCreateInterval(SS, RC); - if (CurrSLI->hasAtLeastOneValue()) - CurrSValNo = CurrSLI->getValNumInfo(0); - else - CurrSValNo = CurrSLI->getNextValue(SlotIndex(), 0, - LSs->getVNInfoAllocator()); - return SS; -} - -/// IsAvailableInStack - Return true if register is available in a split stack -/// slot at the specified index. -bool -PreAllocSplitting::IsAvailableInStack(MachineBasicBlock *DefMBB, - unsigned Reg, SlotIndex DefIndex, - SlotIndex RestoreIndex, - SlotIndex &SpillIndex, - int& SS) const { - if (!DefMBB) - return false; - - DenseMap<unsigned, int>::const_iterator I = IntervalSSMap.find(Reg); - if (I == IntervalSSMap.end()) - return false; - DenseMap<SlotIndex, SlotIndex>::const_iterator - II = Def2SpillMap.find(DefIndex); - if (II == Def2SpillMap.end()) - return false; - - // If last spill of def is in the same mbb as barrier mbb (where restore will - // be), make sure it's not below the intended restore index. - // FIXME: Undo the previous spill? - assert(LIs->getMBBFromIndex(II->second) == DefMBB); - if (DefMBB == BarrierMBB && II->second >= RestoreIndex) - return false; - - SS = I->second; - SpillIndex = II->second; - return true; -} - -/// UpdateSpillSlotInterval - Given the specified val# of the register live -/// interval being split, and the spill and restore indicies, update the live -/// interval of the spill stack slot. -void -PreAllocSplitting::UpdateSpillSlotInterval(VNInfo *ValNo, SlotIndex SpillIndex, - SlotIndex RestoreIndex) { - assert(LIs->getMBBFromIndex(RestoreIndex) == BarrierMBB && - "Expect restore in the barrier mbb"); - - MachineBasicBlock *MBB = LIs->getMBBFromIndex(SpillIndex); - if (MBB == BarrierMBB) { - // Intra-block spill + restore. We are done. - LiveRange SLR(SpillIndex, RestoreIndex, CurrSValNo); - CurrSLI->addRange(SLR); - return; - } - - SmallPtrSet<MachineBasicBlock*, 4> Processed; - SlotIndex EndIdx = LIs->getMBBEndIdx(MBB); - LiveRange SLR(SpillIndex, EndIdx, CurrSValNo); - CurrSLI->addRange(SLR); - Processed.insert(MBB); - - // Start from the spill mbb, figure out the extend of the spill slot's - // live interval. - SmallVector<MachineBasicBlock*, 4> WorkList; - const LiveRange *LR = CurrLI->getLiveRangeContaining(SpillIndex); - if (LR->end > EndIdx) - // If live range extend beyond end of mbb, add successors to work list. - for (MachineBasicBlock::succ_iterator SI = MBB->succ_begin(), - SE = MBB->succ_end(); SI != SE; ++SI) - WorkList.push_back(*SI); - - while (!WorkList.empty()) { - MachineBasicBlock *MBB = WorkList.back(); - WorkList.pop_back(); - if (Processed.count(MBB)) - continue; - SlotIndex Idx = LIs->getMBBStartIdx(MBB); - LR = CurrLI->getLiveRangeContaining(Idx); - if (LR && LR->valno == ValNo) { - EndIdx = LIs->getMBBEndIdx(MBB); - if (Idx <= RestoreIndex && RestoreIndex < EndIdx) { - // Spill slot live interval stops at the restore. - LiveRange SLR(Idx, RestoreIndex, CurrSValNo); - CurrSLI->addRange(SLR); - } else if (LR->end > EndIdx) { - // Live range extends beyond end of mbb, process successors. - LiveRange SLR(Idx, EndIdx.getNextIndex(), CurrSValNo); - CurrSLI->addRange(SLR); - for (MachineBasicBlock::succ_iterator SI = MBB->succ_begin(), - SE = MBB->succ_end(); SI != SE; ++SI) - WorkList.push_back(*SI); - } else { - LiveRange SLR(Idx, LR->end, CurrSValNo); - CurrSLI->addRange(SLR); - } - Processed.insert(MBB); - } - } -} - -/// PerformPHIConstruction - From properly set up use and def lists, use a PHI -/// construction algorithm to compute the ranges and valnos for an interval. -VNInfo* -PreAllocSplitting::PerformPHIConstruction(MachineBasicBlock::iterator UseI, - MachineBasicBlock* MBB, LiveInterval* LI, - SmallPtrSet<MachineInstr*, 4>& Visited, - DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 2> >& Defs, - DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 2> >& Uses, - DenseMap<MachineInstr*, VNInfo*>& NewVNs, - DenseMap<MachineBasicBlock*, VNInfo*>& LiveOut, - DenseMap<MachineBasicBlock*, VNInfo*>& Phis, - bool IsTopLevel, bool IsIntraBlock) { - // Return memoized result if it's available. - if (IsTopLevel && Visited.count(UseI) && NewVNs.count(UseI)) - return NewVNs[UseI]; - else if (!IsTopLevel && IsIntraBlock && NewVNs.count(UseI)) - return NewVNs[UseI]; - else if (!IsIntraBlock && LiveOut.count(MBB)) - return LiveOut[MBB]; - - // Check if our block contains any uses or defs. - bool ContainsDefs = Defs.count(MBB); - bool ContainsUses = Uses.count(MBB); - - VNInfo* RetVNI = 0; - - // Enumerate the cases of use/def contaning blocks. - if (!ContainsDefs && !ContainsUses) { - return PerformPHIConstructionFallBack(UseI, MBB, LI, Visited, Defs, Uses, - NewVNs, LiveOut, Phis, - IsTopLevel, IsIntraBlock); - } else if (ContainsDefs && !ContainsUses) { - SmallPtrSet<MachineInstr*, 2>& BlockDefs = Defs[MBB]; - - // Search for the def in this block. If we don't find it before the - // instruction we care about, go to the fallback case. Note that that - // should never happen: this cannot be intrablock, so use should - // always be an end() iterator. - assert(UseI == MBB->end() && "No use marked in intrablock"); - - MachineBasicBlock::iterator Walker = UseI; - --Walker; - while (Walker != MBB->begin()) { - if (BlockDefs.count(Walker)) - break; - --Walker; - } - - // Once we've found it, extend its VNInfo to our instruction. - SlotIndex DefIndex = LIs->getInstructionIndex(Walker); - DefIndex = DefIndex.getDefIndex(); - SlotIndex EndIndex = LIs->getMBBEndIdx(MBB); - - RetVNI = NewVNs[Walker]; - LI->addRange(LiveRange(DefIndex, EndIndex, RetVNI)); - } else if (!ContainsDefs && ContainsUses) { - SmallPtrSet<MachineInstr*, 2>& BlockUses = Uses[MBB]; - - // Search for the use in this block that precedes the instruction we care - // about, going to the fallback case if we don't find it. - MachineBasicBlock::iterator Walker = UseI; - bool found = false; - while (Walker != MBB->begin()) { - --Walker; - if (BlockUses.count(Walker)) { - found = true; - break; - } - } - - if (!found) - return PerformPHIConstructionFallBack(UseI, MBB, LI, Visited, Defs, - Uses, NewVNs, LiveOut, Phis, - IsTopLevel, IsIntraBlock); - - SlotIndex UseIndex = LIs->getInstructionIndex(Walker); - UseIndex = UseIndex.getUseIndex(); - SlotIndex EndIndex; - if (IsIntraBlock) { - EndIndex = LIs->getInstructionIndex(UseI).getDefIndex(); - } else - EndIndex = LIs->getMBBEndIdx(MBB); - - // Now, recursively phi construct the VNInfo for the use we found, - // and then extend it to include the instruction we care about - RetVNI = PerformPHIConstruction(Walker, MBB, LI, Visited, Defs, Uses, - NewVNs, LiveOut, Phis, false, true); - - LI->addRange(LiveRange(UseIndex, EndIndex, RetVNI)); - - // FIXME: Need to set kills properly for inter-block stuff. - } else if (ContainsDefs && ContainsUses) { - SmallPtrSet<MachineInstr*, 2>& BlockDefs = Defs[MBB]; - SmallPtrSet<MachineInstr*, 2>& BlockUses = Uses[MBB]; - - // This case is basically a merging of the two preceding case, with the - // special note that checking for defs must take precedence over checking - // for uses, because of two-address instructions. - MachineBasicBlock::iterator Walker = UseI; - bool foundDef = false; - bool foundUse = false; - while (Walker != MBB->begin()) { - --Walker; - if (BlockDefs.count(Walker)) { - foundDef = true; - break; - } else if (BlockUses.count(Walker)) { - foundUse = true; - break; - } - } - - if (!foundDef && !foundUse) - return PerformPHIConstructionFallBack(UseI, MBB, LI, Visited, Defs, - Uses, NewVNs, LiveOut, Phis, - IsTopLevel, IsIntraBlock); - - SlotIndex StartIndex = LIs->getInstructionIndex(Walker); - StartIndex = foundDef ? StartIndex.getDefIndex() : StartIndex.getUseIndex(); - SlotIndex EndIndex; - if (IsIntraBlock) { - EndIndex = LIs->getInstructionIndex(UseI).getDefIndex(); - } else - EndIndex = LIs->getMBBEndIdx(MBB); - - if (foundDef) - RetVNI = NewVNs[Walker]; - else - RetVNI = PerformPHIConstruction(Walker, MBB, LI, Visited, Defs, Uses, - NewVNs, LiveOut, Phis, false, true); - - LI->addRange(LiveRange(StartIndex, EndIndex, RetVNI)); - } - - // Memoize results so we don't have to recompute them. - if (!IsIntraBlock) LiveOut[MBB] = RetVNI; - else { - if (!NewVNs.count(UseI)) - NewVNs[UseI] = RetVNI; - Visited.insert(UseI); - } - - return RetVNI; -} - -/// PerformPHIConstructionFallBack - PerformPHIConstruction fall back path. -/// -VNInfo* -PreAllocSplitting::PerformPHIConstructionFallBack(MachineBasicBlock::iterator UseI, - MachineBasicBlock* MBB, LiveInterval* LI, - SmallPtrSet<MachineInstr*, 4>& Visited, - DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 2> >& Defs, - DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 2> >& Uses, - DenseMap<MachineInstr*, VNInfo*>& NewVNs, - DenseMap<MachineBasicBlock*, VNInfo*>& LiveOut, - DenseMap<MachineBasicBlock*, VNInfo*>& Phis, - bool IsTopLevel, bool IsIntraBlock) { - // NOTE: Because this is the fallback case from other cases, we do NOT - // assume that we are not intrablock here. - if (Phis.count(MBB)) return Phis[MBB]; - - SlotIndex StartIndex = LIs->getMBBStartIdx(MBB); - VNInfo *RetVNI = Phis[MBB] = - LI->getNextValue(SlotIndex(), /*FIXME*/ 0, - LIs->getVNInfoAllocator()); - - if (!IsIntraBlock) LiveOut[MBB] = RetVNI; - - // If there are no uses or defs between our starting point and the - // beginning of the block, then recursive perform phi construction - // on our predecessors. - DenseMap<MachineBasicBlock*, VNInfo*> IncomingVNs; - for (MachineBasicBlock::pred_iterator PI = MBB->pred_begin(), - PE = MBB->pred_end(); PI != PE; ++PI) { - VNInfo* Incoming = PerformPHIConstruction((*PI)->end(), *PI, LI, - Visited, Defs, Uses, NewVNs, - LiveOut, Phis, false, false); - if (Incoming != 0) - IncomingVNs[*PI] = Incoming; - } - - if (MBB->pred_size() == 1 && !RetVNI->hasPHIKill()) { - VNInfo* OldVN = RetVNI; - VNInfo* NewVN = IncomingVNs.begin()->second; - VNInfo* MergedVN = LI->MergeValueNumberInto(OldVN, NewVN); - if (MergedVN == OldVN) std::swap(OldVN, NewVN); - - for (DenseMap<MachineBasicBlock*, VNInfo*>::iterator LOI = LiveOut.begin(), - LOE = LiveOut.end(); LOI != LOE; ++LOI) - if (LOI->second == OldVN) - LOI->second = MergedVN; - for (DenseMap<MachineInstr*, VNInfo*>::iterator NVI = NewVNs.begin(), - NVE = NewVNs.end(); NVI != NVE; ++NVI) - if (NVI->second == OldVN) - NVI->second = MergedVN; - for (DenseMap<MachineBasicBlock*, VNInfo*>::iterator PI = Phis.begin(), - PE = Phis.end(); PI != PE; ++PI) - if (PI->second == OldVN) - PI->second = MergedVN; - RetVNI = MergedVN; - } else { - // Otherwise, merge the incoming VNInfos with a phi join. Create a new - // VNInfo to represent the joined value. - for (DenseMap<MachineBasicBlock*, VNInfo*>::iterator I = - IncomingVNs.begin(), E = IncomingVNs.end(); I != E; ++I) { - I->second->setHasPHIKill(true); - } - } - - SlotIndex EndIndex; - if (IsIntraBlock) { - EndIndex = LIs->getInstructionIndex(UseI).getDefIndex(); - } else - EndIndex = LIs->getMBBEndIdx(MBB); - LI->addRange(LiveRange(StartIndex, EndIndex, RetVNI)); - - // Memoize results so we don't have to recompute them. - if (!IsIntraBlock) - LiveOut[MBB] = RetVNI; - else { - if (!NewVNs.count(UseI)) - NewVNs[UseI] = RetVNI; - Visited.insert(UseI); - } - - return RetVNI; -} - -/// ReconstructLiveInterval - Recompute a live interval from scratch. -void PreAllocSplitting::ReconstructLiveInterval(LiveInterval* LI) { - VNInfo::Allocator& Alloc = LIs->getVNInfoAllocator(); - - // Clear the old ranges and valnos; - LI->clear(); - - // Cache the uses and defs of the register - typedef DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 2> > RegMap; - RegMap Defs, Uses; - - // Keep track of the new VNs we're creating. - DenseMap<MachineInstr*, VNInfo*> NewVNs; - SmallPtrSet<VNInfo*, 2> PhiVNs; - - // Cache defs, and create a new VNInfo for each def. - for (MachineRegisterInfo::def_iterator DI = MRI->def_begin(LI->reg), - DE = MRI->def_end(); DI != DE; ++DI) { - Defs[(*DI).getParent()].insert(&*DI); - - SlotIndex DefIdx = LIs->getInstructionIndex(&*DI); - DefIdx = DefIdx.getDefIndex(); - - assert(!DI->isPHI() && "PHI instr in code during pre-alloc splitting."); - VNInfo* NewVN = LI->getNextValue(DefIdx, 0, Alloc); - - // If the def is a move, set the copy field. - if (DI->isCopyLike() && DI->getOperand(0).getReg() == LI->reg) - NewVN->setCopy(&*DI); - - NewVNs[&*DI] = NewVN; - } - - // Cache uses as a separate pass from actually processing them. - for (MachineRegisterInfo::use_iterator UI = MRI->use_begin(LI->reg), - UE = MRI->use_end(); UI != UE; ++UI) - Uses[(*UI).getParent()].insert(&*UI); - - // Now, actually process every use and use a phi construction algorithm - // to walk from it to its reaching definitions, building VNInfos along - // the way. - DenseMap<MachineBasicBlock*, VNInfo*> LiveOut; - DenseMap<MachineBasicBlock*, VNInfo*> Phis; - SmallPtrSet<MachineInstr*, 4> Visited; - for (MachineRegisterInfo::use_iterator UI = MRI->use_begin(LI->reg), - UE = MRI->use_end(); UI != UE; ++UI) { - PerformPHIConstruction(&*UI, UI->getParent(), LI, Visited, Defs, - Uses, NewVNs, LiveOut, Phis, true, true); - } - - // Add ranges for dead defs - for (MachineRegisterInfo::def_iterator DI = MRI->def_begin(LI->reg), - DE = MRI->def_end(); DI != DE; ++DI) { - SlotIndex DefIdx = LIs->getInstructionIndex(&*DI); - DefIdx = DefIdx.getDefIndex(); - - if (LI->liveAt(DefIdx)) continue; - - VNInfo* DeadVN = NewVNs[&*DI]; - LI->addRange(LiveRange(DefIdx, DefIdx.getNextSlot(), DeadVN)); - } -} - -/// RenumberValno - Split the given valno out into a new vreg, allowing it to -/// be allocated to a different register. This function creates a new vreg, -/// copies the valno and its live ranges over to the new vreg's interval, -/// removes them from the old interval, and rewrites all uses and defs of -/// the original reg to the new vreg within those ranges. -void PreAllocSplitting::RenumberValno(VNInfo* VN) { - SmallVector<VNInfo*, 4> Stack; - SmallVector<VNInfo*, 4> VNsToCopy; - Stack.push_back(VN); - - // Walk through and copy the valno we care about, and any other valnos - // that are two-address redefinitions of the one we care about. These - // will need to be rewritten as well. We also check for safety of the - // renumbering here, by making sure that none of the valno involved has - // phi kills. - while (!Stack.empty()) { - VNInfo* OldVN = Stack.back(); - Stack.pop_back(); - - // Bail out if we ever encounter a valno that has a PHI kill. We can't - // renumber these. - if (OldVN->hasPHIKill()) return; - - VNsToCopy.push_back(OldVN); - - // Locate two-address redefinitions - for (MachineRegisterInfo::def_iterator DI = MRI->def_begin(CurrLI->reg), - DE = MRI->def_end(); DI != DE; ++DI) { - if (!DI->isRegTiedToUseOperand(DI.getOperandNo())) continue; - SlotIndex DefIdx = LIs->getInstructionIndex(&*DI).getDefIndex(); - VNInfo* NextVN = CurrLI->findDefinedVNInfoForRegInt(DefIdx); - if (std::find(VNsToCopy.begin(), VNsToCopy.end(), NextVN) != - VNsToCopy.end()) - Stack.push_back(NextVN); - } - } - - // Create the new vreg - unsigned NewVReg = MRI->createVirtualRegister(MRI->getRegClass(CurrLI->reg)); - - // Create the new live interval - LiveInterval& NewLI = LIs->getOrCreateInterval(NewVReg); - - for (SmallVector<VNInfo*, 4>::iterator OI = VNsToCopy.begin(), OE = - VNsToCopy.end(); OI != OE; ++OI) { - VNInfo* OldVN = *OI; - - // Copy the valno over - VNInfo* NewVN = NewLI.createValueCopy(OldVN, LIs->getVNInfoAllocator()); - NewLI.MergeValueInAsValue(*CurrLI, OldVN, NewVN); - - // Remove the valno from the old interval - CurrLI->removeValNo(OldVN); - } - - // Rewrite defs and uses. This is done in two stages to avoid invalidating - // the reg_iterator. - SmallVector<std::pair<MachineInstr*, unsigned>, 8> OpsToChange; - - for (MachineRegisterInfo::reg_iterator I = MRI->reg_begin(CurrLI->reg), - E = MRI->reg_end(); I != E; ++I) { - MachineOperand& MO = I.getOperand(); - SlotIndex InstrIdx = LIs->getInstructionIndex(&*I); - - if ((MO.isUse() && NewLI.liveAt(InstrIdx.getUseIndex())) || - (MO.isDef() && NewLI.liveAt(InstrIdx.getDefIndex()))) - OpsToChange.push_back(std::make_pair(&*I, I.getOperandNo())); - } - - for (SmallVector<std::pair<MachineInstr*, unsigned>, 8>::iterator I = - OpsToChange.begin(), E = OpsToChange.end(); I != E; ++I) { - MachineInstr* Inst = I->first; - unsigned OpIdx = I->second; - MachineOperand& MO = Inst->getOperand(OpIdx); - MO.setReg(NewVReg); - } - - // Grow the VirtRegMap, since we've created a new vreg. - VRM->grow(); - - // The renumbered vreg shares a stack slot with the old register. - if (IntervalSSMap.count(CurrLI->reg)) - IntervalSSMap[NewVReg] = IntervalSSMap[CurrLI->reg]; - - ++NumRenumbers; -} - -bool PreAllocSplitting::Rematerialize(unsigned VReg, VNInfo* ValNo, - MachineInstr* DefMI, - MachineBasicBlock::iterator RestorePt, - SmallPtrSet<MachineInstr*, 4>& RefsInMBB) { - MachineBasicBlock& MBB = *RestorePt->getParent(); - - MachineBasicBlock::iterator KillPt = BarrierMBB->end(); - if (!DefMI || DefMI->getParent() == BarrierMBB) - KillPt = findSpillPoint(BarrierMBB, Barrier, NULL, RefsInMBB); - else - KillPt = llvm::next(MachineBasicBlock::iterator(DefMI)); - - if (KillPt == DefMI->getParent()->end()) - return false; - - TII->reMaterialize(MBB, RestorePt, VReg, 0, DefMI, *TRI); - SlotIndex RematIdx = LIs->InsertMachineInstrInMaps(prior(RestorePt)); - - ReconstructLiveInterval(CurrLI); - RematIdx = RematIdx.getDefIndex(); - RenumberValno(CurrLI->findDefinedVNInfoForRegInt(RematIdx)); - - ++NumSplits; - ++NumRemats; - return true; -} - -MachineInstr* PreAllocSplitting::FoldSpill(unsigned vreg, - const TargetRegisterClass* RC, - MachineInstr* DefMI, - MachineInstr* Barrier, - MachineBasicBlock* MBB, - int& SS, - SmallPtrSet<MachineInstr*, 4>& RefsInMBB) { - // Go top down if RefsInMBB is empty. - if (RefsInMBB.empty()) - return 0; - - MachineBasicBlock::iterator FoldPt = Barrier; - while (&*FoldPt != DefMI && FoldPt != MBB->begin() && - !RefsInMBB.count(FoldPt)) - --FoldPt; - - int OpIdx = FoldPt->findRegisterDefOperandIdx(vreg); - if (OpIdx == -1) - return 0; - - SmallVector<unsigned, 1> Ops; - Ops.push_back(OpIdx); - - if (!TII->canFoldMemoryOperand(FoldPt, Ops)) - return 0; - - DenseMap<unsigned, int>::iterator I = IntervalSSMap.find(vreg); - if (I != IntervalSSMap.end()) { - SS = I->second; - } else { - SS = MFI->CreateSpillStackObject(RC->getSize(), RC->getAlignment()); - } - - MachineInstr* FMI = TII->foldMemoryOperand(FoldPt, Ops, SS); - - if (FMI) { - LIs->ReplaceMachineInstrInMaps(FoldPt, FMI); - FoldPt->eraseFromParent(); - ++NumFolds; - - IntervalSSMap[vreg] = SS; - CurrSLI = &LSs->getOrCreateInterval(SS, RC); - if (CurrSLI->hasAtLeastOneValue()) - CurrSValNo = CurrSLI->getValNumInfo(0); - else - CurrSValNo = CurrSLI->getNextValue(SlotIndex(), 0, - LSs->getVNInfoAllocator()); - } - - return FMI; -} - -MachineInstr* PreAllocSplitting::FoldRestore(unsigned vreg, - const TargetRegisterClass* RC, - MachineInstr* Barrier, - MachineBasicBlock* MBB, - int SS, - SmallPtrSet<MachineInstr*, 4>& RefsInMBB) { - if ((int)RestoreFoldLimit != -1 && RestoreFoldLimit == (int)NumRestoreFolds) - return 0; - - // Go top down if RefsInMBB is empty. - if (RefsInMBB.empty()) - return 0; - - // Can't fold a restore between a call stack setup and teardown. - MachineBasicBlock::iterator FoldPt = Barrier; - - // Advance from barrier to call frame teardown. - while (FoldPt != MBB->getFirstTerminator() && - FoldPt->getOpcode() != TRI->getCallFrameDestroyOpcode()) { - if (RefsInMBB.count(FoldPt)) - return 0; - - ++FoldPt; - } - - if (FoldPt == MBB->getFirstTerminator()) - return 0; - else - ++FoldPt; - - // Now find the restore point. - while (FoldPt != MBB->getFirstTerminator() && !RefsInMBB.count(FoldPt)) { - if (FoldPt->getOpcode() == TRI->getCallFrameSetupOpcode()) { - while (FoldPt != MBB->getFirstTerminator() && - FoldPt->getOpcode() != TRI->getCallFrameDestroyOpcode()) { - if (RefsInMBB.count(FoldPt)) - return 0; - - ++FoldPt; - } - - if (FoldPt == MBB->getFirstTerminator()) - return 0; - } - - ++FoldPt; - } - - if (FoldPt == MBB->getFirstTerminator()) - return 0; - - int OpIdx = FoldPt->findRegisterUseOperandIdx(vreg, true); - if (OpIdx == -1) - return 0; - - SmallVector<unsigned, 1> Ops; - Ops.push_back(OpIdx); - - if (!TII->canFoldMemoryOperand(FoldPt, Ops)) - return 0; - - MachineInstr* FMI = TII->foldMemoryOperand(FoldPt, Ops, SS); - - if (FMI) { - LIs->ReplaceMachineInstrInMaps(FoldPt, FMI); - FoldPt->eraseFromParent(); - ++NumRestoreFolds; - } - - return FMI; -} - -/// SplitRegLiveInterval - Split (spill and restore) the given live interval -/// so it would not cross the barrier that's being processed. Shrink wrap -/// (minimize) the live interval to the last uses. -bool PreAllocSplitting::SplitRegLiveInterval(LiveInterval *LI) { - DEBUG(dbgs() << "Pre-alloc splitting " << LI->reg << " for " << *Barrier - << " result: "); - - CurrLI = LI; - - // Find live range where current interval cross the barrier. - LiveInterval::iterator LR = - CurrLI->FindLiveRangeContaining(BarrierIdx.getUseIndex()); - VNInfo *ValNo = LR->valno; - - assert(!ValNo->isUnused() && "Val# is defined by a dead def?"); - - MachineInstr *DefMI = LIs->getInstructionFromIndex(ValNo->def); - - // If this would create a new join point, do not split. - if (DefMI && createsNewJoin(LR, DefMI->getParent(), Barrier->getParent())) { - DEBUG(dbgs() << "FAILED (would create a new join point).\n"); - return false; - } - - // Find all references in the barrier mbb. - SmallPtrSet<MachineInstr*, 4> RefsInMBB; - for (MachineRegisterInfo::reg_iterator I = MRI->reg_begin(CurrLI->reg), - E = MRI->reg_end(); I != E; ++I) { - MachineInstr *RefMI = &*I; - if (RefMI->getParent() == BarrierMBB) - RefsInMBB.insert(RefMI); - } - - // Find a point to restore the value after the barrier. - MachineBasicBlock::iterator RestorePt = - findRestorePoint(BarrierMBB, Barrier, LR->end, RefsInMBB); - if (RestorePt == BarrierMBB->end()) { - DEBUG(dbgs() << "FAILED (could not find a suitable restore point).\n"); - return false; - } - - if (DefMI && LIs->isReMaterializable(*LI, ValNo, DefMI)) - if (Rematerialize(LI->reg, ValNo, DefMI, RestorePt, RefsInMBB)) { - DEBUG(dbgs() << "success (remat).\n"); - return true; - } - - // Add a spill either before the barrier or after the definition. - MachineBasicBlock *DefMBB = DefMI ? DefMI->getParent() : NULL; - const TargetRegisterClass *RC = MRI->getRegClass(CurrLI->reg); - SlotIndex SpillIndex; - MachineInstr *SpillMI = NULL; - int SS = -1; - if (!DefMI) { - // If we don't know where the def is we must split just before the barrier. - if ((SpillMI = FoldSpill(LI->reg, RC, 0, Barrier, - BarrierMBB, SS, RefsInMBB))) { - SpillIndex = LIs->getInstructionIndex(SpillMI); - } else { - MachineBasicBlock::iterator SpillPt = - findSpillPoint(BarrierMBB, Barrier, NULL, RefsInMBB); - if (SpillPt == BarrierMBB->begin()) { - DEBUG(dbgs() << "FAILED (could not find a suitable spill point).\n"); - return false; // No gap to insert spill. - } - // Add spill. - - SS = CreateSpillStackSlot(CurrLI->reg, RC); - TII->storeRegToStackSlot(*BarrierMBB, SpillPt, CurrLI->reg, true, SS, RC, - TRI); - SpillMI = prior(SpillPt); - SpillIndex = LIs->InsertMachineInstrInMaps(SpillMI); - } - } else if (!IsAvailableInStack(DefMBB, CurrLI->reg, ValNo->def, - LIs->getZeroIndex(), SpillIndex, SS)) { - // If it's already split, just restore the value. There is no need to spill - // the def again. - if (!DefMI) { - DEBUG(dbgs() << "FAILED (def is dead).\n"); - return false; // Def is dead. Do nothing. - } - - if ((SpillMI = FoldSpill(LI->reg, RC, DefMI, Barrier, - BarrierMBB, SS, RefsInMBB))) { - SpillIndex = LIs->getInstructionIndex(SpillMI); - } else { - // Check if it's possible to insert a spill after the def MI. - MachineBasicBlock::iterator SpillPt; - if (DefMBB == BarrierMBB) { - // Add spill after the def and the last use before the barrier. - SpillPt = findSpillPoint(BarrierMBB, Barrier, DefMI, - RefsInMBB); - if (SpillPt == DefMBB->begin()) { - DEBUG(dbgs() << "FAILED (could not find a suitable spill point).\n"); - return false; // No gap to insert spill. - } - } else { - SpillPt = llvm::next(MachineBasicBlock::iterator(DefMI)); - if (SpillPt == DefMBB->end()) { - DEBUG(dbgs() << "FAILED (could not find a suitable spill point).\n"); - return false; // No gap to insert spill. - } - } - // Add spill. - SS = CreateSpillStackSlot(CurrLI->reg, RC); - TII->storeRegToStackSlot(*DefMBB, SpillPt, CurrLI->reg, false, SS, RC, - TRI); - SpillMI = prior(SpillPt); - SpillIndex = LIs->InsertMachineInstrInMaps(SpillMI); - } - } - - // Remember def instruction index to spill index mapping. - if (DefMI && SpillMI) - Def2SpillMap[ValNo->def] = SpillIndex; - - // Add restore. - bool FoldedRestore = false; - SlotIndex RestoreIndex; - if (MachineInstr* LMI = FoldRestore(CurrLI->reg, RC, Barrier, - BarrierMBB, SS, RefsInMBB)) { - RestorePt = LMI; - RestoreIndex = LIs->getInstructionIndex(RestorePt); - FoldedRestore = true; - } else { - TII->loadRegFromStackSlot(*BarrierMBB, RestorePt, CurrLI->reg, SS, RC, TRI); - MachineInstr *LoadMI = prior(RestorePt); - RestoreIndex = LIs->InsertMachineInstrInMaps(LoadMI); - } - - // Update spill stack slot live interval. - UpdateSpillSlotInterval(ValNo, SpillIndex.getUseIndex().getNextSlot(), - RestoreIndex.getDefIndex()); - - ReconstructLiveInterval(CurrLI); - - if (!FoldedRestore) { - SlotIndex RestoreIdx = LIs->getInstructionIndex(prior(RestorePt)); - RestoreIdx = RestoreIdx.getDefIndex(); - RenumberValno(CurrLI->findDefinedVNInfoForRegInt(RestoreIdx)); - } - - ++NumSplits; - DEBUG(dbgs() << "success.\n"); - return true; -} - -/// SplitRegLiveIntervals - Split all register live intervals that cross the -/// barrier that's being processed. -bool -PreAllocSplitting::SplitRegLiveIntervals(const TargetRegisterClass **RCs, - SmallPtrSet<LiveInterval*, 8>& Split) { - // First find all the virtual registers whose live intervals are intercepted - // by the current barrier. - SmallVector<LiveInterval*, 8> Intervals; - for (const TargetRegisterClass **RC = RCs; *RC; ++RC) { - // FIXME: If it's not safe to move any instruction that defines the barrier - // register class, then it means there are some special dependencies which - // codegen is not modelling. Ignore these barriers for now. - if (!TII->isSafeToMoveRegClassDefs(*RC)) - continue; - const std::vector<unsigned> &VRs = MRI->getRegClassVirtRegs(*RC); - for (unsigned i = 0, e = VRs.size(); i != e; ++i) { - unsigned Reg = VRs[i]; - if (!LIs->hasInterval(Reg)) - continue; - LiveInterval *LI = &LIs->getInterval(Reg); - if (LI->liveAt(BarrierIdx) && !Barrier->readsRegister(Reg)) - // Virtual register live interval is intercepted by the barrier. We - // should split and shrink wrap its interval if possible. - Intervals.push_back(LI); - } - } - - // Process the affected live intervals. - bool Change = false; - while (!Intervals.empty()) { - if (PreSplitLimit != -1 && (int)NumSplits == PreSplitLimit) - break; - LiveInterval *LI = Intervals.back(); - Intervals.pop_back(); - bool result = SplitRegLiveInterval(LI); - if (result) Split.insert(LI); - Change |= result; - } - - return Change; -} - -unsigned PreAllocSplitting::getNumberOfNonSpills( - SmallPtrSet<MachineInstr*, 4>& MIs, - unsigned Reg, int FrameIndex, - bool& FeedsTwoAddr) { - unsigned NonSpills = 0; - for (SmallPtrSet<MachineInstr*, 4>::iterator UI = MIs.begin(), UE = MIs.end(); - UI != UE; ++UI) { - int StoreFrameIndex; - unsigned StoreVReg = TII->isStoreToStackSlot(*UI, StoreFrameIndex); - if (StoreVReg != Reg || StoreFrameIndex != FrameIndex) - ++NonSpills; - - int DefIdx = (*UI)->findRegisterDefOperandIdx(Reg); - if (DefIdx != -1 && (*UI)->isRegTiedToUseOperand(DefIdx)) - FeedsTwoAddr = true; - } - - return NonSpills; -} - -/// removeDeadSpills - After doing splitting, filter through all intervals we've -/// split, and see if any of the spills are unnecessary. If so, remove them. -bool PreAllocSplitting::removeDeadSpills(SmallPtrSet<LiveInterval*, 8>& split) { - bool changed = false; - - // Walk over all of the live intervals that were touched by the splitter, - // and see if we can do any DCE and/or folding. - for (SmallPtrSet<LiveInterval*, 8>::iterator LI = split.begin(), - LE = split.end(); LI != LE; ++LI) { - DenseMap<VNInfo*, SmallPtrSet<MachineInstr*, 4> > VNUseCount; - - // First, collect all the uses of the vreg, and sort them by their - // reaching definition (VNInfo). - for (MachineRegisterInfo::use_iterator UI = MRI->use_begin((*LI)->reg), - UE = MRI->use_end(); UI != UE; ++UI) { - SlotIndex index = LIs->getInstructionIndex(&*UI); - index = index.getUseIndex(); - - const LiveRange* LR = (*LI)->getLiveRangeContaining(index); - VNUseCount[LR->valno].insert(&*UI); - } - - // Now, take the definitions (VNInfo's) one at a time and try to DCE - // and/or fold them away. - for (LiveInterval::vni_iterator VI = (*LI)->vni_begin(), - VE = (*LI)->vni_end(); VI != VE; ++VI) { - - if (DeadSplitLimit != -1 && (int)NumDeadSpills == DeadSplitLimit) - return changed; - - VNInfo* CurrVN = *VI; - - // We don't currently try to handle definitions with PHI kills, because - // it would involve processing more than one VNInfo at once. - if (CurrVN->hasPHIKill()) continue; - - // We also don't try to handle the results of PHI joins, since there's - // no defining instruction to analyze. - MachineInstr* DefMI = LIs->getInstructionFromIndex(CurrVN->def); - if (!DefMI || CurrVN->isUnused()) continue; - - // We're only interested in eliminating cruft introduced by the splitter, - // is of the form load-use or load-use-store. First, check that the - // definition is a load, and remember what stack slot we loaded it from. - int FrameIndex; - if (!TII->isLoadFromStackSlot(DefMI, FrameIndex)) continue; - - // If the definition has no uses at all, just DCE it. - if (VNUseCount[CurrVN].size() == 0) { - LIs->RemoveMachineInstrFromMaps(DefMI); - (*LI)->removeValNo(CurrVN); - DefMI->eraseFromParent(); - VNUseCount.erase(CurrVN); - ++NumDeadSpills; - changed = true; - continue; - } - - // Second, get the number of non-store uses of the definition, as well as - // a flag indicating whether it feeds into a later two-address definition. - bool FeedsTwoAddr = false; - unsigned NonSpillCount = getNumberOfNonSpills(VNUseCount[CurrVN], - (*LI)->reg, FrameIndex, - FeedsTwoAddr); - - // If there's one non-store use and it doesn't feed a two-addr, then - // this is a load-use-store case that we can try to fold. - if (NonSpillCount == 1 && !FeedsTwoAddr) { - // Start by finding the non-store use MachineInstr. - SmallPtrSet<MachineInstr*, 4>::iterator UI = VNUseCount[CurrVN].begin(); - int StoreFrameIndex; - unsigned StoreVReg = TII->isStoreToStackSlot(*UI, StoreFrameIndex); - while (UI != VNUseCount[CurrVN].end() && - (StoreVReg == (*LI)->reg && StoreFrameIndex == FrameIndex)) { - ++UI; - if (UI != VNUseCount[CurrVN].end()) - StoreVReg = TII->isStoreToStackSlot(*UI, StoreFrameIndex); - } - if (UI == VNUseCount[CurrVN].end()) continue; - - MachineInstr* use = *UI; - - // Attempt to fold it away! - int OpIdx = use->findRegisterUseOperandIdx((*LI)->reg, false); - if (OpIdx == -1) continue; - SmallVector<unsigned, 1> Ops; - Ops.push_back(OpIdx); - if (!TII->canFoldMemoryOperand(use, Ops)) continue; - - MachineInstr* NewMI = TII->foldMemoryOperand(use, Ops, FrameIndex); - - if (!NewMI) continue; - - // Update relevant analyses. - LIs->RemoveMachineInstrFromMaps(DefMI); - LIs->ReplaceMachineInstrInMaps(use, NewMI); - (*LI)->removeValNo(CurrVN); - - DefMI->eraseFromParent(); - use->eraseFromParent(); - VNUseCount[CurrVN].erase(use); - - // Remove deleted instructions. Note that we need to remove them from - // the VNInfo->use map as well, just to be safe. - for (SmallPtrSet<MachineInstr*, 4>::iterator II = - VNUseCount[CurrVN].begin(), IE = VNUseCount[CurrVN].end(); - II != IE; ++II) { - for (DenseMap<VNInfo*, SmallPtrSet<MachineInstr*, 4> >::iterator - VNI = VNUseCount.begin(), VNE = VNUseCount.end(); VNI != VNE; - ++VNI) - if (VNI->first != CurrVN) - VNI->second.erase(*II); - LIs->RemoveMachineInstrFromMaps(*II); - (*II)->eraseFromParent(); - } - - VNUseCount.erase(CurrVN); - - for (DenseMap<VNInfo*, SmallPtrSet<MachineInstr*, 4> >::iterator - VI = VNUseCount.begin(), VE = VNUseCount.end(); VI != VE; ++VI) - if (VI->second.erase(use)) - VI->second.insert(NewMI); - - ++NumDeadSpills; - changed = true; - continue; - } - - // If there's more than one non-store instruction, we can't profitably - // fold it, so bail. - if (NonSpillCount) continue; - - // Otherwise, this is a load-store case, so DCE them. - for (SmallPtrSet<MachineInstr*, 4>::iterator UI = - VNUseCount[CurrVN].begin(), UE = VNUseCount[CurrVN].end(); - UI != UE; ++UI) { - LIs->RemoveMachineInstrFromMaps(*UI); - (*UI)->eraseFromParent(); - } - - VNUseCount.erase(CurrVN); - - LIs->RemoveMachineInstrFromMaps(DefMI); - (*LI)->removeValNo(CurrVN); - DefMI->eraseFromParent(); - ++NumDeadSpills; - changed = true; - } - } - - return changed; -} - -bool PreAllocSplitting::createsNewJoin(LiveRange* LR, - MachineBasicBlock* DefMBB, - MachineBasicBlock* BarrierMBB) { - if (DefMBB == BarrierMBB) - return false; - - if (LR->valno->hasPHIKill()) - return false; - - SlotIndex MBBEnd = LIs->getMBBEndIdx(BarrierMBB); - if (LR->end < MBBEnd) - return false; - - MachineLoopInfo& MLI = getAnalysis<MachineLoopInfo>(); - if (MLI.getLoopFor(DefMBB) != MLI.getLoopFor(BarrierMBB)) - return true; - - MachineDominatorTree& MDT = getAnalysis<MachineDominatorTree>(); - SmallPtrSet<MachineBasicBlock*, 4> Visited; - typedef std::pair<MachineBasicBlock*, - MachineBasicBlock::succ_iterator> ItPair; - SmallVector<ItPair, 4> Stack; - Stack.push_back(std::make_pair(BarrierMBB, BarrierMBB->succ_begin())); - - while (!Stack.empty()) { - ItPair P = Stack.back(); - Stack.pop_back(); - - MachineBasicBlock* PredMBB = P.first; - MachineBasicBlock::succ_iterator S = P.second; - - if (S == PredMBB->succ_end()) - continue; - else if (Visited.count(*S)) { - Stack.push_back(std::make_pair(PredMBB, ++S)); - continue; - } else - Stack.push_back(std::make_pair(PredMBB, S+1)); - - MachineBasicBlock* MBB = *S; - Visited.insert(MBB); - - if (MBB == BarrierMBB) - return true; - - MachineDomTreeNode* DefMDTN = MDT.getNode(DefMBB); - MachineDomTreeNode* BarrierMDTN = MDT.getNode(BarrierMBB); - MachineDomTreeNode* MDTN = MDT.getNode(MBB)->getIDom(); - while (MDTN) { - if (MDTN == DefMDTN) - return true; - else if (MDTN == BarrierMDTN) - break; - MDTN = MDTN->getIDom(); - } - - MBBEnd = LIs->getMBBEndIdx(MBB); - if (LR->end > MBBEnd) - Stack.push_back(std::make_pair(MBB, MBB->succ_begin())); - } - - return false; -} - - -bool PreAllocSplitting::runOnMachineFunction(MachineFunction &MF) { - CurrMF = &MF; - TM = &MF.getTarget(); - TRI = TM->getRegisterInfo(); - TII = TM->getInstrInfo(); - MFI = MF.getFrameInfo(); - MRI = &MF.getRegInfo(); - SIs = &getAnalysis<SlotIndexes>(); - LIs = &getAnalysis<LiveIntervals>(); - LSs = &getAnalysis<LiveStacks>(); - VRM = &getAnalysis<VirtRegMap>(); - - bool MadeChange = false; - - // Make sure blocks are numbered in order. - MF.RenumberBlocks(); - - MachineBasicBlock *Entry = MF.begin(); - SmallPtrSet<MachineBasicBlock*,16> Visited; - - SmallPtrSet<LiveInterval*, 8> Split; - - for (df_ext_iterator<MachineBasicBlock*, SmallPtrSet<MachineBasicBlock*,16> > - DFI = df_ext_begin(Entry, Visited), E = df_ext_end(Entry, Visited); - DFI != E; ++DFI) { - BarrierMBB = *DFI; - for (MachineBasicBlock::iterator I = BarrierMBB->begin(), - E = BarrierMBB->end(); I != E; ++I) { - Barrier = &*I; - const TargetRegisterClass **BarrierRCs = - Barrier->getDesc().getRegClassBarriers(); - if (!BarrierRCs) - continue; - BarrierIdx = LIs->getInstructionIndex(Barrier); - MadeChange |= SplitRegLiveIntervals(BarrierRCs, Split); - } - } - - MadeChange |= removeDeadSpills(Split); - - return MadeChange; -} |
