X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FSplitKit.cpp;h=b69a3078ac9c8dd7fc17b54dc590563d61cfbe3f;hb=bf824efcb92aa54d4a7ecc4afff9282c860a3f38;hp=7ed9089ecd0267aff4f2bf4673cfae125c48fc28;hpb=b5fa9333431673aac2ced8dea80152349a85cf6f;p=oota-llvm.git diff --git a/lib/CodeGen/SplitKit.cpp b/lib/CodeGen/SplitKit.cpp index 7ed9089ecd0..b69a3078ac9 100644 --- a/lib/CodeGen/SplitKit.cpp +++ b/lib/CodeGen/SplitKit.cpp @@ -16,11 +16,11 @@ #include "SplitKit.h" #include "LiveRangeEdit.h" #include "VirtRegMap.h" +#include "llvm/ADT/Statistic.h" #include "llvm/CodeGen/CalcSpillWeights.h" #include "llvm/CodeGen/LiveIntervalAnalysis.h" #include "llvm/CodeGen/MachineDominators.h" #include "llvm/CodeGen/MachineInstrBuilder.h" -#include "llvm/CodeGen/MachineLoopInfo.h" #include "llvm/CodeGen/MachineRegisterInfo.h" #include "llvm/Support/CommandLine.h" #include "llvm/Support/Debug.h" @@ -34,505 +34,427 @@ static cl::opt AllowSplit("spiller-splits-edges", cl::desc("Allow critical edge splitting during spilling")); +STATISTIC(NumFinished, "Number of splits finished"); +STATISTIC(NumSimple, "Number of splits that were simple"); + //===----------------------------------------------------------------------===// // Split Analysis //===----------------------------------------------------------------------===// -SplitAnalysis::SplitAnalysis(const MachineFunction &mf, +SplitAnalysis::SplitAnalysis(const VirtRegMap &vrm, const LiveIntervals &lis, const MachineLoopInfo &mli) - : mf_(mf), - lis_(lis), - loops_(mli), - tii_(*mf.getTarget().getInstrInfo()), - curli_(0) {} + : MF(vrm.getMachineFunction()), + VRM(vrm), + LIS(lis), + Loops(mli), + TII(*MF.getTarget().getInstrInfo()), + CurLI(0) {} void SplitAnalysis::clear() { UseSlots.clear(); - usingInstrs_.clear(); - usingBlocks_.clear(); - usingLoops_.clear(); - curli_ = 0; + UsingInstrs.clear(); + UsingBlocks.clear(); + LiveBlocks.clear(); + CurLI = 0; } bool SplitAnalysis::canAnalyzeBranch(const MachineBasicBlock *MBB) { MachineBasicBlock *T, *F; SmallVector Cond; - return !tii_.AnalyzeBranch(const_cast(*MBB), T, F, Cond); + return !TII.AnalyzeBranch(const_cast(*MBB), T, F, Cond); } -/// analyzeUses - Count instructions, basic blocks, and loops using curli. +/// analyzeUses - Count instructions, basic blocks, and loops using CurLI. void SplitAnalysis::analyzeUses() { - const MachineRegisterInfo &MRI = mf_.getRegInfo(); - for (MachineRegisterInfo::reg_iterator I = MRI.reg_begin(curli_->reg); - MachineInstr *MI = I.skipInstruction();) { - if (MI->isDebugValue() || !usingInstrs_.insert(MI)) + const MachineRegisterInfo &MRI = MF.getRegInfo(); + for (MachineRegisterInfo::reg_iterator I = MRI.reg_begin(CurLI->reg), + E = MRI.reg_end(); I != E; ++I) { + MachineOperand &MO = I.getOperand(); + if (MO.isUse() && MO.isUndef()) continue; - UseSlots.push_back(lis_.getInstructionIndex(MI).getDefIndex()); - MachineBasicBlock *MBB = MI->getParent(); - if (usingBlocks_[MBB]++) + MachineInstr *MI = MO.getParent(); + if (MI->isDebugValue() || !UsingInstrs.insert(MI)) continue; - for (MachineLoop *Loop = loops_.getLoopFor(MBB); Loop; - Loop = Loop->getParentLoop()) - usingLoops_[Loop]++; + UseSlots.push_back(LIS.getInstructionIndex(MI).getDefIndex()); + MachineBasicBlock *MBB = MI->getParent(); + UsingBlocks[MBB]++; } array_pod_sort(UseSlots.begin(), UseSlots.end()); - DEBUG(dbgs() << " counted " - << usingInstrs_.size() << " instrs, " - << usingBlocks_.size() << " blocks, " - << usingLoops_.size() << " loops.\n"); -} -void SplitAnalysis::print(const BlockPtrSet &B, raw_ostream &OS) const { - for (BlockPtrSet::const_iterator I = B.begin(), E = B.end(); I != E; ++I) { - unsigned count = usingBlocks_.lookup(*I); - OS << " BB#" << (*I)->getNumber(); - if (count) - OS << '(' << count << ')'; + // Compute per-live block info. + if (!calcLiveBlockInfo()) { + // FIXME: calcLiveBlockInfo found inconsistencies in the live range. + // I am looking at you, SimpleRegisterCoalescing! + DEBUG(dbgs() << "*** Fixing inconsistent live interval! ***\n"); + const_cast(LIS) + .shrinkToUses(const_cast(CurLI)); + LiveBlocks.clear(); + bool fixed = calcLiveBlockInfo(); + (void)fixed; + assert(fixed && "Couldn't fix broken live interval"); } -} -// Get three sets of basic blocks surrounding a loop: Blocks inside the loop, -// predecessor blocks, and exit blocks. -void SplitAnalysis::getLoopBlocks(const MachineLoop *Loop, LoopBlocks &Blocks) { - Blocks.clear(); - - // Blocks in the loop. - Blocks.Loop.insert(Loop->block_begin(), Loop->block_end()); - - // Predecessor blocks. - const MachineBasicBlock *Header = Loop->getHeader(); - for (MachineBasicBlock::const_pred_iterator I = Header->pred_begin(), - E = Header->pred_end(); I != E; ++I) - if (!Blocks.Loop.count(*I)) - Blocks.Preds.insert(*I); - - // Exit blocks. - for (MachineLoop::block_iterator I = Loop->block_begin(), - E = Loop->block_end(); I != E; ++I) { - const MachineBasicBlock *MBB = *I; - for (MachineBasicBlock::const_succ_iterator SI = MBB->succ_begin(), - SE = MBB->succ_end(); SI != SE; ++SI) - if (!Blocks.Loop.count(*SI)) - Blocks.Exits.insert(*SI); - } + DEBUG(dbgs() << " counted " + << UsingInstrs.size() << " instrs, " + << UsingBlocks.size() << " blocks.\n"); } -void SplitAnalysis::print(const LoopBlocks &B, raw_ostream &OS) const { - OS << "Loop:"; - print(B.Loop, OS); - OS << ", preds:"; - print(B.Preds, OS); - OS << ", exits:"; - print(B.Exits, OS); -} +/// calcLiveBlockInfo - Fill the LiveBlocks array with information about blocks +/// where CurLI is live. +bool SplitAnalysis::calcLiveBlockInfo() { + if (CurLI->empty()) + return true; -/// analyzeLoopPeripheralUse - Return an enum describing how curli_ is used in -/// and around the Loop. -SplitAnalysis::LoopPeripheralUse SplitAnalysis:: -analyzeLoopPeripheralUse(const SplitAnalysis::LoopBlocks &Blocks) { - LoopPeripheralUse use = ContainedInLoop; - for (BlockCountMap::iterator I = usingBlocks_.begin(), E = usingBlocks_.end(); - I != E; ++I) { - const MachineBasicBlock *MBB = I->first; - // Is this a peripheral block? - if (use < MultiPeripheral && - (Blocks.Preds.count(MBB) || Blocks.Exits.count(MBB))) { - if (I->second > 1) use = MultiPeripheral; - else use = SinglePeripheral; - continue; - } - // Is it a loop block? - if (Blocks.Loop.count(MBB)) - continue; - // It must be an unrelated block. - DEBUG(dbgs() << ", outside: BB#" << MBB->getNumber()); - return OutsideLoop; - } - return use; -} + LiveInterval::const_iterator LVI = CurLI->begin(); + LiveInterval::const_iterator LVE = CurLI->end(); -/// getCriticalExits - It may be necessary to partially break critical edges -/// leaving the loop if an exit block has predecessors from outside the loop -/// periphery. -void SplitAnalysis::getCriticalExits(const SplitAnalysis::LoopBlocks &Blocks, - BlockPtrSet &CriticalExits) { - CriticalExits.clear(); - - // A critical exit block has curli live-in, and has a predecessor that is not - // in the loop nor a loop predecessor. For such an exit block, the edges - // carrying the new variable must be moved to a new pre-exit block. - for (BlockPtrSet::iterator I = Blocks.Exits.begin(), E = Blocks.Exits.end(); - I != E; ++I) { - const MachineBasicBlock *Exit = *I; - // A single-predecessor exit block is definitely not a critical edge. - if (Exit->pred_size() == 1) - continue; - // This exit may not have curli live in at all. No need to split. - if (!lis_.isLiveInToMBB(*curli_, Exit)) - continue; - // Does this exit block have a predecessor that is not a loop block or loop - // predecessor? - for (MachineBasicBlock::const_pred_iterator PI = Exit->pred_begin(), - PE = Exit->pred_end(); PI != PE; ++PI) { - const MachineBasicBlock *Pred = *PI; - if (Blocks.Loop.count(Pred) || Blocks.Preds.count(Pred)) - continue; - // This is a critical exit block, and we need to split the exit edge. - CriticalExits.insert(Exit); - break; - } - } -} + SmallVectorImpl::const_iterator UseI, UseE; + UseI = UseSlots.begin(); + UseE = UseSlots.end(); -void SplitAnalysis::getCriticalPreds(const SplitAnalysis::LoopBlocks &Blocks, - BlockPtrSet &CriticalPreds) { - CriticalPreds.clear(); - - // A critical predecessor block has curli live-out, and has a successor that - // has curli live-in and is not in the loop nor a loop exit block. For such a - // predecessor block, we must carry the value in both the 'inside' and - // 'outside' registers. - for (BlockPtrSet::iterator I = Blocks.Preds.begin(), E = Blocks.Preds.end(); - I != E; ++I) { - const MachineBasicBlock *Pred = *I; - // Definitely not a critical edge. - if (Pred->succ_size() == 1) - continue; - // This block may not have curli live out at all if there is a PHI. - if (!lis_.isLiveOutOfMBB(*curli_, Pred)) - continue; - // Does this block have a successor outside the loop? - for (MachineBasicBlock::const_pred_iterator SI = Pred->succ_begin(), - SE = Pred->succ_end(); SI != SE; ++SI) { - const MachineBasicBlock *Succ = *SI; - if (Blocks.Loop.count(Succ) || Blocks.Exits.count(Succ)) - continue; - if (!lis_.isLiveInToMBB(*curli_, Succ)) - continue; - // This is a critical predecessor block. - CriticalPreds.insert(Pred); - break; + // Loop over basic blocks where CurLI is live. + MachineFunction::iterator MFI = LIS.getMBBFromIndex(LVI->start); + for (;;) { + BlockInfo BI; + BI.MBB = MFI; + tie(BI.Start, BI.Stop) = LIS.getSlotIndexes()->getMBBRange(BI.MBB); + + // The last split point is the latest possible insertion point that dominates + // all successor blocks. If interference reaches LastSplitPoint, it is not + // possible to insert a split or reload that makes CurLI live in the + // outgoing bundle. + MachineBasicBlock::iterator LSP = LIS.getLastSplitPoint(*CurLI, BI.MBB); + if (LSP == BI.MBB->end()) + BI.LastSplitPoint = BI.Stop; + else + BI.LastSplitPoint = LIS.getInstructionIndex(LSP); + + // LVI is the first live segment overlapping MBB. + BI.LiveIn = LVI->start <= BI.Start; + if (!BI.LiveIn) + BI.Def = LVI->start; + + // Find the first and last uses in the block. + BI.Uses = hasUses(MFI); + if (BI.Uses && UseI != UseE) { + BI.FirstUse = *UseI; + assert(BI.FirstUse >= BI.Start); + do ++UseI; + while (UseI != UseE && *UseI < BI.Stop); + BI.LastUse = UseI[-1]; + assert(BI.LastUse < BI.Stop); } - } -} -/// canSplitCriticalExits - Return true if it is possible to insert new exit -/// blocks before the blocks in CriticalExits. -bool -SplitAnalysis::canSplitCriticalExits(const SplitAnalysis::LoopBlocks &Blocks, - BlockPtrSet &CriticalExits) { - // If we don't allow critical edge splitting, require no critical exits. - if (!AllowSplit) - return CriticalExits.empty(); - - for (BlockPtrSet::iterator I = CriticalExits.begin(), E = CriticalExits.end(); - I != E; ++I) { - const MachineBasicBlock *Succ = *I; - // We want to insert a new pre-exit MBB before Succ, and change all the - // in-loop blocks to branch to the pre-exit instead of Succ. - // Check that all the in-loop predecessors can be changed. - for (MachineBasicBlock::const_pred_iterator PI = Succ->pred_begin(), - PE = Succ->pred_end(); PI != PE; ++PI) { - const MachineBasicBlock *Pred = *PI; - // The external predecessors won't be altered. - if (!Blocks.Loop.count(Pred) && !Blocks.Preds.count(Pred)) - continue; - if (!canAnalyzeBranch(Pred)) - return false; + // Look for gaps in the live range. + bool hasGap = false; + BI.LiveOut = true; + while (LVI->end < BI.Stop) { + SlotIndex LastStop = LVI->end; + if (++LVI == LVE || LVI->start >= BI.Stop) { + BI.Kill = LastStop; + BI.LiveOut = false; + break; + } + if (LastStop < LVI->start) { + hasGap = true; + BI.Kill = LastStop; + BI.Def = LVI->start; + } } - // If Succ's layout predecessor falls through, that too must be analyzable. - // We need to insert the pre-exit block in the gap. - MachineFunction::const_iterator MFI = Succ; - if (MFI == mf_.begin()) - continue; - if (!canAnalyzeBranch(--MFI)) + // Don't set LiveThrough when the block has a gap. + BI.LiveThrough = !hasGap && BI.LiveIn && BI.LiveOut; + LiveBlocks.push_back(BI); + + // FIXME: This should never happen. The live range stops or starts without a + // corresponding use. An earlier pass did something wrong. + if (!BI.LiveThrough && !BI.Uses) return false; - } - // No problems found. - return true; -} -void SplitAnalysis::analyze(const LiveInterval *li) { - clear(); - curli_ = li; - analyzeUses(); -} + // LVI is now at LVE or LVI->end >= Stop. + if (LVI == LVE) + break; -void SplitAnalysis::getSplitLoops(LoopPtrSet &Loops) { - assert(curli_ && "Call analyze() before getSplitLoops"); - if (usingLoops_.empty()) - return; + // Live segment ends exactly at Stop. Move to the next segment. + if (LVI->end == BI.Stop && ++LVI == LVE) + break; - LoopBlocks Blocks; - BlockPtrSet CriticalExits; + // Pick the next basic block. + if (LVI->start < BI.Stop) + ++MFI; + else + MFI = LIS.getMBBFromIndex(LVI->start); + } + return true; +} - // We split around loops where curli is used outside the periphery. - for (LoopCountMap::const_iterator I = usingLoops_.begin(), - E = usingLoops_.end(); I != E; ++I) { - const MachineLoop *Loop = I->first; - getLoopBlocks(Loop, Blocks); - DEBUG({ dbgs() << " "; print(Blocks, dbgs()); }); +bool SplitAnalysis::isOriginalEndpoint(SlotIndex Idx) const { + unsigned OrigReg = VRM.getOriginal(CurLI->reg); + const LiveInterval &Orig = LIS.getInterval(OrigReg); + assert(!Orig.empty() && "Splitting empty interval?"); + LiveInterval::const_iterator I = Orig.find(Idx); - switch(analyzeLoopPeripheralUse(Blocks)) { - case OutsideLoop: - break; - case MultiPeripheral: - // FIXME: We could split a live range with multiple uses in a peripheral - // block and still make progress. However, it is possible that splitting - // another live range will insert copies into a peripheral block, and - // there is a small chance we can enter an infinite loop, inserting copies - // forever. - // For safety, stick to splitting live ranges with uses outside the - // periphery. - DEBUG(dbgs() << ": multiple peripheral uses"); - break; - case ContainedInLoop: - DEBUG(dbgs() << ": fully contained\n"); - continue; - case SinglePeripheral: - DEBUG(dbgs() << ": single peripheral use\n"); - continue; - } - // Will it be possible to split around this loop? - getCriticalExits(Blocks, CriticalExits); - DEBUG(dbgs() << ": " << CriticalExits.size() << " critical exits\n"); - if (!canSplitCriticalExits(Blocks, CriticalExits)) - continue; - // This is a possible split. - Loops.insert(Loop); - } + // Range containing Idx should begin at Idx. + if (I != Orig.end() && I->start <= Idx) + return I->start == Idx; - DEBUG(dbgs() << " getSplitLoops found " << Loops.size() - << " candidate loops.\n"); + // Range does not contain Idx, previous must end at Idx. + return I != Orig.begin() && (--I)->end == Idx; } -const MachineLoop *SplitAnalysis::getBestSplitLoop() { - LoopPtrSet Loops; - getSplitLoops(Loops); - if (Loops.empty()) - return 0; - - // Pick the earliest loop. - // FIXME: Are there other heuristics to consider? - const MachineLoop *Best = 0; - SlotIndex BestIdx; - for (LoopPtrSet::const_iterator I = Loops.begin(), E = Loops.end(); I != E; - ++I) { - SlotIndex Idx = lis_.getMBBStartIdx((*I)->getHeader()); - if (!Best || Idx < BestIdx) - Best = *I, BestIdx = Idx; +void SplitAnalysis::print(const BlockPtrSet &B, raw_ostream &OS) const { + for (BlockPtrSet::const_iterator I = B.begin(), E = B.end(); I != E; ++I) { + unsigned count = UsingBlocks.lookup(*I); + OS << " BB#" << (*I)->getNumber(); + if (count) + OS << '(' << count << ')'; } - DEBUG(dbgs() << " getBestSplitLoop found " << *Best); - return Best; -} - -/// isBypassLoop - Return true if curli is live through Loop and has no uses -/// inside the loop. Bypass loops are candidates for splitting because it can -/// prevent interference inside the loop. -bool SplitAnalysis::isBypassLoop(const MachineLoop *Loop) { - // If curli is live into the loop header and there are no uses in the loop, it - // must be live in the entire loop and live on at least one exiting edge. - return !usingLoops_.count(Loop) && - lis_.isLiveInToMBB(*curli_, Loop->getHeader()); } -/// getBypassLoops - Get all the maximal bypass loops. These are the bypass -/// loops whose parent is not a bypass loop. -void SplitAnalysis::getBypassLoops(LoopPtrSet &BypassLoops) { - SmallVector Todo(loops_.begin(), loops_.end()); - while (!Todo.empty()) { - MachineLoop *Loop = Todo.pop_back_val(); - if (!usingLoops_.count(Loop)) { - // This is either a bypass loop or completely irrelevant. - if (lis_.isLiveInToMBB(*curli_, Loop->getHeader())) - BypassLoops.insert(Loop); - // Either way, skip the child loops. - continue; - } - - // The child loops may be bypass loops. - Todo.append(Loop->begin(), Loop->end()); - } +void SplitAnalysis::analyze(const LiveInterval *li) { + clear(); + CurLI = li; + analyzeUses(); } //===----------------------------------------------------------------------===// -// LiveIntervalMap +// Split Editor //===----------------------------------------------------------------------===// -// Work around the fact that the std::pair constructors are broken for pointer -// pairs in some implementations. makeVV(x, 0) works. -static inline std::pair -makeVV(const VNInfo *a, VNInfo *b) { - return std::make_pair(a, b); -} +/// Create a new SplitEditor for editing the LiveInterval analyzed by SA. +SplitEditor::SplitEditor(SplitAnalysis &sa, + LiveIntervals &lis, + VirtRegMap &vrm, + MachineDominatorTree &mdt) + : SA(sa), LIS(lis), VRM(vrm), + MRI(vrm.getMachineFunction().getRegInfo()), + MDT(mdt), + TII(*vrm.getMachineFunction().getTarget().getInstrInfo()), + TRI(*vrm.getMachineFunction().getTarget().getRegisterInfo()), + Edit(0), + OpenIdx(0), + RegAssign(Allocator) +{} + +void SplitEditor::reset(LiveRangeEdit &lre) { + Edit = &lre; + OpenIdx = 0; + RegAssign.clear(); + Values.clear(); + + // We don't need to clear LiveOutCache, only LiveOutSeen entries are read. + LiveOutSeen.clear(); -void LiveIntervalMap::reset(LiveInterval *li) { - li_ = li; - valueMap_.clear(); - liveOutCache_.clear(); + // We don't need an AliasAnalysis since we will only be performing + // cheap-as-a-copy remats anyway. + Edit->anyRematerializable(LIS, TII, 0); } -bool LiveIntervalMap::isComplexMapped(const VNInfo *ParentVNI) const { - ValueMap::const_iterator i = valueMap_.find(ParentVNI); - return i != valueMap_.end() && i->second == 0; +void SplitEditor::dump() const { + if (RegAssign.empty()) { + dbgs() << " empty\n"; + return; + } + + for (RegAssignMap::const_iterator I = RegAssign.begin(); I.valid(); ++I) + dbgs() << " [" << I.start() << ';' << I.stop() << "):" << I.value(); + dbgs() << '\n'; } -// defValue - Introduce a li_ def for ParentVNI that could be later than -// ParentVNI->def. -VNInfo *LiveIntervalMap::defValue(const VNInfo *ParentVNI, SlotIndex Idx) { - assert(li_ && "call reset first"); +VNInfo *SplitEditor::defValue(unsigned RegIdx, + const VNInfo *ParentVNI, + SlotIndex Idx) { assert(ParentVNI && "Mapping NULL value"); assert(Idx.isValid() && "Invalid SlotIndex"); - assert(parentli_.getVNInfoAt(Idx) == ParentVNI && "Bad ParentVNI"); + assert(Edit->getParent().getVNInfoAt(Idx) == ParentVNI && "Bad Parent VNI"); + LiveInterval *LI = Edit->get(RegIdx); // Create a new value. - VNInfo *VNI = li_->getNextValue(Idx, 0, lis_.getVNInfoAllocator()); - - // Preserve the PHIDef bit. - if (ParentVNI->isPHIDef() && Idx == ParentVNI->def) - VNI->setIsPHIDef(true); + VNInfo *VNI = LI->getNextValue(Idx, 0, LIS.getVNInfoAllocator()); // Use insert for lookup, so we can add missing values with a second lookup. - std::pair InsP = - valueMap_.insert(makeVV(ParentVNI, Idx == ParentVNI->def ? VNI : 0)); + std::pair InsP = + Values.insert(std::make_pair(std::make_pair(RegIdx, ParentVNI->id), VNI)); + + // This was the first time (RegIdx, ParentVNI) was mapped. + // Keep it as a simple def without any liveness. + if (InsP.second) + return VNI; - // This is now a complex def. Mark with a NULL in valueMap. - if (!InsP.second) + // If the previous value was a simple mapping, add liveness for it now. + if (VNInfo *OldVNI = InsP.first->second) { + SlotIndex Def = OldVNI->def; + LI->addRange(LiveRange(Def, Def.getNextSlot(), OldVNI)); + // No longer a simple mapping. InsP.first->second = 0; + } + + // This is a complex mapping, add liveness for VNI + SlotIndex Def = VNI->def; + LI->addRange(LiveRange(Def, Def.getNextSlot(), VNI)); return VNI; } - -// mapValue - Find the mapped value for ParentVNI at Idx. -// Potentially create phi-def values. -VNInfo *LiveIntervalMap::mapValue(const VNInfo *ParentVNI, SlotIndex Idx, - bool *simple) { - assert(li_ && "call reset first"); +void SplitEditor::markComplexMapped(unsigned RegIdx, const VNInfo *ParentVNI) { assert(ParentVNI && "Mapping NULL value"); - assert(Idx.isValid() && "Invalid SlotIndex"); - assert(parentli_.getVNInfoAt(Idx) == ParentVNI && "Bad ParentVNI"); + VNInfo *&VNI = Values[std::make_pair(RegIdx, ParentVNI->id)]; - // Use insert for lookup, so we can add missing values with a second lookup. - std::pair InsP = - valueMap_.insert(makeVV(ParentVNI, 0)); - - // This was an unknown value. Create a simple mapping. - if (InsP.second) { - if (simple) *simple = true; - return InsP.first->second = li_->createValueCopy(ParentVNI, - lis_.getVNInfoAllocator()); - } + // ParentVNI was either unmapped or already complex mapped. Either way. + if (!VNI) + return; - // This was a simple mapped value. - if (InsP.first->second) { - if (simple) *simple = true; - return InsP.first->second; - } + // This was previously a single mapping. Make sure the old def is represented + // by a trivial live range. + SlotIndex Def = VNI->def; + Edit->get(RegIdx)->addRange(LiveRange(Def, Def.getNextSlot(), VNI)); + VNI = 0; +} - // This is a complex mapped value. There may be multiple defs, and we may need - // to create phi-defs. - if (simple) *simple = false; - MachineBasicBlock *IdxMBB = lis_.getMBBFromIndex(Idx); +// extendRange - Extend the live range to reach Idx. +// Potentially create phi-def values. +void SplitEditor::extendRange(unsigned RegIdx, SlotIndex Idx) { + assert(Idx.isValid() && "Invalid SlotIndex"); + MachineBasicBlock *IdxMBB = LIS.getMBBFromIndex(Idx); assert(IdxMBB && "No MBB at Idx"); + LiveInterval *LI = Edit->get(RegIdx); // Is there a def in the same MBB we can extend? - if (VNInfo *VNI = extendTo(IdxMBB, Idx)) - return VNI; + if (LI->extendInBlock(LIS.getMBBStartIdx(IdxMBB), Idx)) + return; // Now for the fun part. We know that ParentVNI potentially has multiple defs, // and we may need to create even more phi-defs to preserve VNInfo SSA form. // Perform a search for all predecessor blocks where we know the dominating // VNInfo. Insert phi-def VNInfos along the path back to IdxMBB. - DEBUG(dbgs() << "\n Reaching defs for BB#" << IdxMBB->getNumber() - << " at " << Idx << " in " << *li_ << '\n'); - // Blocks where li_ should be live-in. + // Initialize the live-out cache the first time it is needed. + if (LiveOutSeen.empty()) { + unsigned N = VRM.getMachineFunction().getNumBlockIDs(); + LiveOutSeen.resize(N); + LiveOutCache.resize(N); + } + + // Blocks where LI should be live-in. SmallVector LiveIn; - LiveIn.push_back(mdt_[IdxMBB]); + LiveIn.push_back(MDT[IdxMBB]); + + // Remember if we have seen more than one value. + bool UniqueVNI = true; + VNInfo *IdxVNI = 0; - // Using liveOutCache_ as a visited set, perform a BFS for all reaching defs. + // Using LiveOutCache as a visited set, perform a BFS for all reaching defs. for (unsigned i = 0; i != LiveIn.size(); ++i) { MachineBasicBlock *MBB = LiveIn[i]->getBlock(); + assert(!MBB->pred_empty() && "Value live-in to entry block?"); for (MachineBasicBlock::pred_iterator PI = MBB->pred_begin(), PE = MBB->pred_end(); PI != PE; ++PI) { MachineBasicBlock *Pred = *PI; + LiveOutPair &LOP = LiveOutCache[Pred]; + // Is this a known live-out block? - std::pair LOIP = - liveOutCache_.insert(std::make_pair(Pred, LiveOutPair())); - // Yes, we have been here before. - if (!LOIP.second) { - DEBUG(if (VNInfo *VNI = LOIP.first->second.first) - dbgs() << " known valno #" << VNI->id - << " at BB#" << Pred->getNumber() << '\n'); + if (LiveOutSeen.test(Pred->getNumber())) { + if (VNInfo *VNI = LOP.first) { + if (IdxVNI && IdxVNI != VNI) + UniqueVNI = false; + IdxVNI = VNI; + } continue; } + // First time. LOP is garbage and must be cleared below. + LiveOutSeen.set(Pred->getNumber()); + // Does Pred provide a live-out value? - SlotIndex Last = lis_.getMBBEndIdx(Pred).getPrevSlot(); - if (VNInfo *VNI = extendTo(Pred, Last)) { - MachineBasicBlock *DefMBB = lis_.getMBBFromIndex(VNI->def); - DEBUG(dbgs() << " found valno #" << VNI->id - << " from BB#" << DefMBB->getNumber() - << " at BB#" << Pred->getNumber() << '\n'); - LiveOutPair &LOP = LOIP.first->second; - LOP.first = VNI; - LOP.second = mdt_[DefMBB]; + SlotIndex Start, Last; + tie(Start, Last) = LIS.getSlotIndexes()->getMBBRange(Pred); + Last = Last.getPrevSlot(); + VNInfo *VNI = LI->extendInBlock(Start, Last); + LOP.first = VNI; + if (VNI) { + LOP.second = MDT[LIS.getMBBFromIndex(VNI->def)]; + if (IdxVNI && IdxVNI != VNI) + UniqueVNI = false; + IdxVNI = VNI; continue; } + LOP.second = 0; + // No, we need a live-in value for Pred as well if (Pred != IdxMBB) - LiveIn.push_back(mdt_[Pred]); + LiveIn.push_back(MDT[Pred]); + else + UniqueVNI = false; // Loopback to IdxMBB, ask updateSSA() for help. } } // We may need to add phi-def values to preserve the SSA form. + if (UniqueVNI) { + LiveOutPair LOP(IdxVNI, MDT[LIS.getMBBFromIndex(IdxVNI->def)]); + // Update LiveOutCache, but skip IdxMBB at LiveIn[0]. + for (unsigned i = 1, e = LiveIn.size(); i != e; ++i) + LiveOutCache[LiveIn[i]->getBlock()] = LOP; + } else + IdxVNI = updateSSA(RegIdx, LiveIn, Idx, IdxMBB); + + // Since we went through the trouble of a full BFS visiting all reaching defs, + // the values in LiveIn are now accurate. No more phi-defs are needed + // for these blocks, so we can color the live ranges. + for (unsigned i = 0, e = LiveIn.size(); i != e; ++i) { + MachineBasicBlock *MBB = LiveIn[i]->getBlock(); + SlotIndex Start = LIS.getMBBStartIdx(MBB); + VNInfo *VNI = LiveOutCache[MBB].first; + + // Anything in LiveIn other than IdxMBB is live-through. + // In IdxMBB, we should stop at Idx unless the same value is live-out. + if (MBB == IdxMBB && IdxVNI != VNI) + LI->addRange(LiveRange(Start, Idx.getNextSlot(), IdxVNI)); + else + LI->addRange(LiveRange(Start, LIS.getMBBEndIdx(MBB), VNI)); + } +} + +VNInfo *SplitEditor::updateSSA(unsigned RegIdx, + SmallVectorImpl &LiveIn, + SlotIndex Idx, + const MachineBasicBlock *IdxMBB) { // This is essentially the same iterative algorithm that SSAUpdater uses, // except we already have a dominator tree, so we don't have to recompute it. + LiveInterval *LI = Edit->get(RegIdx); VNInfo *IdxVNI = 0; unsigned Changes; do { Changes = 0; - DEBUG(dbgs() << " Iterating over " << LiveIn.size() << " blocks.\n"); - // Propagate live-out values down the dominator tree, inserting phi-defs when - // necessary. Since LiveIn was created by a BFS, going backwards makes it more - // likely for us to visit immediate dominators before their children. + // Propagate live-out values down the dominator tree, inserting phi-defs + // when necessary. Since LiveIn was created by a BFS, going backwards makes + // it more likely for us to visit immediate dominators before their + // children. for (unsigned i = LiveIn.size(); i; --i) { MachineDomTreeNode *Node = LiveIn[i-1]; MachineBasicBlock *MBB = Node->getBlock(); MachineDomTreeNode *IDom = Node->getIDom(); LiveOutPair IDomValue; + // We need a live-in value to a block with no immediate dominator? // This is probably an unreachable block that has survived somehow. - bool needPHI = !IDom; - - // Get the IDom live-out value. - if (!needPHI) { - LiveOutMap::iterator I = liveOutCache_.find(IDom->getBlock()); - if (I != liveOutCache_.end()) - IDomValue = I->second; - else - // If IDom is outside our set of live-out blocks, there must be new - // defs, and we need a phi-def here. - needPHI = true; - } + bool needPHI = !IDom || !LiveOutSeen.test(IDom->getBlock()->getNumber()); // IDom dominates all of our predecessors, but it may not be the immediate // dominator. Check if any of them have live-out values that are properly // dominated by IDom. If so, we need a phi-def here. if (!needPHI) { + IDomValue = LiveOutCache[IDom->getBlock()]; for (MachineBasicBlock::pred_iterator PI = MBB->pred_begin(), PE = MBB->pred_end(); PI != PE; ++PI) { - LiveOutPair Value = liveOutCache_[*PI]; + LiveOutPair Value = LiveOutCache[*PI]; if (!Value.first || Value.first == IDomValue.first) continue; // This predecessor is carrying something other than IDomValue. // It could be because IDomValue hasn't propagated yet, or it could be // because MBB is in the dominance frontier of that value. - if (mdt_.dominates(IDom, Value.second)) { + if (MDT.dominates(IDom, Value.second)) { needPHI = true; break; } @@ -542,496 +464,410 @@ VNInfo *LiveIntervalMap::mapValue(const VNInfo *ParentVNI, SlotIndex Idx, // Create a phi-def if required. if (needPHI) { ++Changes; - SlotIndex Start = lis_.getMBBStartIdx(MBB); - VNInfo *VNI = li_->getNextValue(Start, 0, lis_.getVNInfoAllocator()); + SlotIndex Start = LIS.getMBBStartIdx(MBB); + VNInfo *VNI = LI->getNextValue(Start, 0, LIS.getVNInfoAllocator()); VNI->setIsPHIDef(true); - DEBUG(dbgs() << " - BB#" << MBB->getNumber() - << " phi-def #" << VNI->id << " at " << Start << '\n'); - // We no longer need li_ to be live-in. + // We no longer need LI to be live-in. LiveIn.erase(LiveIn.begin()+(i-1)); // Blocks in LiveIn are either IdxMBB, or have a value live-through. if (MBB == IdxMBB) IdxVNI = VNI; // Check if we need to update live-out info. - LiveOutMap::iterator I = liveOutCache_.find(MBB); - if (I == liveOutCache_.end() || I->second.second == Node) { + LiveOutPair &LOP = LiveOutCache[MBB]; + if (LOP.second == Node || !LiveOutSeen.test(MBB->getNumber())) { // We already have a live-out defined in MBB, so this must be IdxMBB. assert(MBB == IdxMBB && "Adding phi-def to known live-out"); - li_->addRange(LiveRange(Start, Idx.getNextSlot(), VNI)); + LI->addRange(LiveRange(Start, Idx.getNextSlot(), VNI)); } else { // This phi-def is also live-out, so color the whole block. - li_->addRange(LiveRange(Start, lis_.getMBBEndIdx(MBB), VNI)); - I->second = LiveOutPair(VNI, Node); + LI->addRange(LiveRange(Start, LIS.getMBBEndIdx(MBB), VNI)); + LOP = LiveOutPair(VNI, Node); } } else if (IDomValue.first) { // No phi-def here. Remember incoming value for IdxMBB. - if (MBB == IdxMBB) + if (MBB == IdxMBB) { IdxVNI = IDomValue.first; + // IdxMBB need not be live-out. + if (!LiveOutSeen.test(MBB->getNumber())) + continue; + } + assert(LiveOutSeen.test(MBB->getNumber()) && "Expected live-out block"); // Propagate IDomValue if needed: // MBB is live-out and doesn't define its own value. - LiveOutMap::iterator I = liveOutCache_.find(MBB); - if (I != liveOutCache_.end() && I->second.second != Node && - I->second.first != IDomValue.first) { + LiveOutPair &LOP = LiveOutCache[MBB]; + if (LOP.second != Node && LOP.first != IDomValue.first) { ++Changes; - I->second = IDomValue; - DEBUG(dbgs() << " - BB#" << MBB->getNumber() - << " idom valno #" << IDomValue.first->id - << " from BB#" << IDom->getBlock()->getNumber() << '\n'); + LOP = IDomValue; } } } - DEBUG(dbgs() << " - made " << Changes << " changes.\n"); } while (Changes); assert(IdxVNI && "Didn't find value for Idx"); - -#ifndef NDEBUG - // Check the liveOutCache_ invariants. - for (LiveOutMap::iterator I = liveOutCache_.begin(), E = liveOutCache_.end(); - I != E; ++I) { - assert(I->first && "Null MBB entry in cache"); - assert(I->second.first && "Null VNInfo in cache"); - assert(I->second.second && "Null DomTreeNode in cache"); - if (I->second.second->getBlock() == I->first) - continue; - for (MachineBasicBlock::pred_iterator PI = I->first->pred_begin(), - PE = I->first->pred_end(); PI != PE; ++PI) - assert(liveOutCache_.lookup(*PI) == I->second && "Bad invariant"); - } -#endif - - // Since we went through the trouble of a full BFS visiting all reaching defs, - // the values in LiveIn are now accurate. No more phi-defs are needed - // for these blocks, so we can color the live ranges. - // This makes the next mapValue call much faster. - for (unsigned i = 0, e = LiveIn.size(); i != e; ++i) { - MachineBasicBlock *MBB = LiveIn[i]->getBlock(); - SlotIndex Start = lis_.getMBBStartIdx(MBB); - if (MBB == IdxMBB) { - li_->addRange(LiveRange(Start, Idx.getNextSlot(), IdxVNI)); - continue; - } - // Anything in LiveIn other than IdxMBB is live-through. - VNInfo *VNI = liveOutCache_.lookup(MBB).first; - assert(VNI && "Missing block value"); - li_->addRange(LiveRange(Start, lis_.getMBBEndIdx(MBB), VNI)); - } - return IdxVNI; } -// extendTo - Find the last li_ value defined in MBB at or before Idx. The -// parentli_ is assumed to be live at Idx. Extend the live range to Idx. -// Return the found VNInfo, or NULL. -VNInfo *LiveIntervalMap::extendTo(const MachineBasicBlock *MBB, SlotIndex Idx) { - assert(li_ && "call reset first"); - LiveInterval::iterator I = std::upper_bound(li_->begin(), li_->end(), Idx); - if (I == li_->begin()) - return 0; - --I; - if (I->end <= lis_.getMBBStartIdx(MBB)) - return 0; - if (I->end <= Idx) - I->end = Idx.getNextSlot(); - return I->valno; -} - -// addSimpleRange - Add a simple range from parentli_ to li_. -// ParentVNI must be live in the [Start;End) interval. -void LiveIntervalMap::addSimpleRange(SlotIndex Start, SlotIndex End, - const VNInfo *ParentVNI) { - assert(li_ && "call reset first"); - bool simple; - VNInfo *VNI = mapValue(ParentVNI, Start, &simple); - // A simple mapping is easy. - if (simple) { - li_->addRange(LiveRange(Start, End, VNI)); - return; - } - - // ParentVNI is a complex value. We must map per MBB. - MachineFunction::iterator MBB = lis_.getMBBFromIndex(Start); - MachineFunction::iterator MBBE = lis_.getMBBFromIndex(End.getPrevSlot()); - - if (MBB == MBBE) { - li_->addRange(LiveRange(Start, End, VNI)); - return; - } - - // First block. - li_->addRange(LiveRange(Start, lis_.getMBBEndIdx(MBB), VNI)); - - // Run sequence of full blocks. - for (++MBB; MBB != MBBE; ++MBB) { - Start = lis_.getMBBStartIdx(MBB); - li_->addRange(LiveRange(Start, lis_.getMBBEndIdx(MBB), - mapValue(ParentVNI, Start))); - } - - // Final block. - Start = lis_.getMBBStartIdx(MBB); - if (Start != End) - li_->addRange(LiveRange(Start, End, mapValue(ParentVNI, Start))); -} - -/// addRange - Add live ranges to li_ where [Start;End) intersects parentli_. -/// All needed values whose def is not inside [Start;End) must be defined -/// beforehand so mapValue will work. -void LiveIntervalMap::addRange(SlotIndex Start, SlotIndex End) { - assert(li_ && "call reset first"); - LiveInterval::const_iterator B = parentli_.begin(), E = parentli_.end(); - LiveInterval::const_iterator I = std::lower_bound(B, E, Start); - - // Check if --I begins before Start and overlaps. - if (I != B) { - --I; - if (I->end > Start) - addSimpleRange(Start, std::min(End, I->end), I->valno); - ++I; - } - - // The remaining ranges begin after Start. - for (;I != E && I->start < End; ++I) - addSimpleRange(I->start, std::min(End, I->end), I->valno); -} - - -//===----------------------------------------------------------------------===// -// Split Editor -//===----------------------------------------------------------------------===// - -/// Create a new SplitEditor for editing the LiveInterval analyzed by SA. -SplitEditor::SplitEditor(SplitAnalysis &sa, - LiveIntervals &lis, - VirtRegMap &vrm, - MachineDominatorTree &mdt, - LiveRangeEdit &edit) - : sa_(sa), lis_(lis), vrm_(vrm), - mri_(vrm.getMachineFunction().getRegInfo()), - tii_(*vrm.getMachineFunction().getTarget().getInstrInfo()), - tri_(*vrm.getMachineFunction().getTarget().getRegisterInfo()), - edit_(edit), - dupli_(lis_, mdt, edit.getParent()), - openli_(lis_, mdt, edit.getParent()) -{ - // We don't need an AliasAnalysis since we will only be performing - // cheap-as-a-copy remats anyway. - edit_.anyRematerializable(lis_, tii_, 0); -} - -bool SplitEditor::intervalsLiveAt(SlotIndex Idx) const { - for (LiveRangeEdit::iterator I = edit_.begin(), E = edit_.end(); I != E; ++I) - if (*I != dupli_.getLI() && (*I)->liveAt(Idx)) - return true; - return false; -} - -VNInfo *SplitEditor::defFromParent(LiveIntervalMap &Reg, +VNInfo *SplitEditor::defFromParent(unsigned RegIdx, VNInfo *ParentVNI, SlotIndex UseIdx, MachineBasicBlock &MBB, MachineBasicBlock::iterator I) { - VNInfo *VNI = 0; MachineInstr *CopyMI = 0; SlotIndex Def; + LiveInterval *LI = Edit->get(RegIdx); // Attempt cheap-as-a-copy rematerialization. LiveRangeEdit::Remat RM(ParentVNI); - if (edit_.canRematerializeAt(RM, UseIdx, true, lis_)) { - Def = edit_.rematerializeAt(MBB, I, Reg.getLI()->reg, RM, - lis_, tii_, tri_); + if (Edit->canRematerializeAt(RM, UseIdx, true, LIS)) { + Def = Edit->rematerializeAt(MBB, I, LI->reg, RM, LIS, TII, TRI); } else { // Can't remat, just insert a copy from parent. - CopyMI = BuildMI(MBB, I, DebugLoc(), tii_.get(TargetOpcode::COPY), - Reg.getLI()->reg).addReg(edit_.getReg()); - Def = lis_.InsertMachineInstrInMaps(CopyMI).getDefIndex(); + CopyMI = BuildMI(MBB, I, DebugLoc(), TII.get(TargetOpcode::COPY), LI->reg) + .addReg(Edit->getReg()); + Def = LIS.InsertMachineInstrInMaps(CopyMI).getDefIndex(); } // Define the value in Reg. - VNI = Reg.defValue(ParentVNI, Def); + VNInfo *VNI = defValue(RegIdx, ParentVNI, Def); VNI->setCopy(CopyMI); - - // Add minimal liveness for the new value. - if (UseIdx < Def) - UseIdx = Def; - Reg.getLI()->addRange(LiveRange(Def, UseIdx.getNextSlot(), VNI)); return VNI; } /// Create a new virtual register and live interval. void SplitEditor::openIntv() { - assert(!openli_.getLI() && "Previous LI not closed before openIntv"); - if (!dupli_.getLI()) - dupli_.reset(&edit_.create(mri_, lis_, vrm_)); + assert(!OpenIdx && "Previous LI not closed before openIntv"); + + // Create the complement as index 0. + if (Edit->empty()) + Edit->create(LIS, VRM); - openli_.reset(&edit_.create(mri_, lis_, vrm_)); + // Create the open interval. + OpenIdx = Edit->size(); + Edit->create(LIS, VRM); } -/// enterIntvBefore - Enter openli before the instruction at Idx. If curli is -/// not live before Idx, a COPY is not inserted. -void SplitEditor::enterIntvBefore(SlotIndex Idx) { - assert(openli_.getLI() && "openIntv not called before enterIntvBefore"); - Idx = Idx.getUseIndex(); +SlotIndex SplitEditor::enterIntvBefore(SlotIndex Idx) { + assert(OpenIdx && "openIntv not called before enterIntvBefore"); DEBUG(dbgs() << " enterIntvBefore " << Idx); - VNInfo *ParentVNI = edit_.getParent().getVNInfoAt(Idx); + Idx = Idx.getBaseIndex(); + VNInfo *ParentVNI = Edit->getParent().getVNInfoAt(Idx); if (!ParentVNI) { DEBUG(dbgs() << ": not live\n"); - return; + return Idx; } - DEBUG(dbgs() << ": valno " << ParentVNI->id); - truncatedValues.insert(ParentVNI); - MachineInstr *MI = lis_.getInstructionFromIndex(Idx); + DEBUG(dbgs() << ": valno " << ParentVNI->id << '\n'); + MachineInstr *MI = LIS.getInstructionFromIndex(Idx); assert(MI && "enterIntvBefore called with invalid index"); - defFromParent(openli_, ParentVNI, Idx, *MI->getParent(), MI); - - DEBUG(dbgs() << ": " << *openli_.getLI() << '\n'); + VNInfo *VNI = defFromParent(OpenIdx, ParentVNI, Idx, *MI->getParent(), MI); + return VNI->def; } -/// enterIntvAtEnd - Enter openli at the end of MBB. -void SplitEditor::enterIntvAtEnd(MachineBasicBlock &MBB) { - assert(openli_.getLI() && "openIntv not called before enterIntvAtEnd"); - SlotIndex End = lis_.getMBBEndIdx(&MBB).getPrevSlot(); - DEBUG(dbgs() << " enterIntvAtEnd BB#" << MBB.getNumber() << ", " << End); - VNInfo *ParentVNI = edit_.getParent().getVNInfoAt(End); +SlotIndex SplitEditor::enterIntvAtEnd(MachineBasicBlock &MBB) { + assert(OpenIdx && "openIntv not called before enterIntvAtEnd"); + SlotIndex End = LIS.getMBBEndIdx(&MBB); + SlotIndex Last = End.getPrevSlot(); + DEBUG(dbgs() << " enterIntvAtEnd BB#" << MBB.getNumber() << ", " << Last); + VNInfo *ParentVNI = Edit->getParent().getVNInfoAt(Last); if (!ParentVNI) { DEBUG(dbgs() << ": not live\n"); - return; + return End; } DEBUG(dbgs() << ": valno " << ParentVNI->id); - truncatedValues.insert(ParentVNI); - defFromParent(openli_, ParentVNI, End, MBB, MBB.getFirstTerminator()); - DEBUG(dbgs() << ": " << *openli_.getLI() << '\n'); + VNInfo *VNI = defFromParent(OpenIdx, ParentVNI, Last, MBB, + LIS.getLastSplitPoint(Edit->getParent(), &MBB)); + RegAssign.insert(VNI->def, End, OpenIdx); + DEBUG(dump()); + return VNI->def; } -/// useIntv - indicate that all instructions in MBB should use openli. +/// useIntv - indicate that all instructions in MBB should use OpenLI. void SplitEditor::useIntv(const MachineBasicBlock &MBB) { - useIntv(lis_.getMBBStartIdx(&MBB), lis_.getMBBEndIdx(&MBB)); + useIntv(LIS.getMBBStartIdx(&MBB), LIS.getMBBEndIdx(&MBB)); } void SplitEditor::useIntv(SlotIndex Start, SlotIndex End) { - assert(openli_.getLI() && "openIntv not called before useIntv"); - openli_.addRange(Start, End); - DEBUG(dbgs() << " use [" << Start << ';' << End << "): " - << *openli_.getLI() << '\n'); + assert(OpenIdx && "openIntv not called before useIntv"); + DEBUG(dbgs() << " useIntv [" << Start << ';' << End << "):"); + RegAssign.insert(Start, End, OpenIdx); + DEBUG(dump()); } -/// leaveIntvAfter - Leave openli after the instruction at Idx. -void SplitEditor::leaveIntvAfter(SlotIndex Idx) { - assert(openli_.getLI() && "openIntv not called before leaveIntvAfter"); +SlotIndex SplitEditor::leaveIntvAfter(SlotIndex Idx) { + assert(OpenIdx && "openIntv not called before leaveIntvAfter"); DEBUG(dbgs() << " leaveIntvAfter " << Idx); // The interval must be live beyond the instruction at Idx. Idx = Idx.getBoundaryIndex(); - VNInfo *ParentVNI = edit_.getParent().getVNInfoAt(Idx); + VNInfo *ParentVNI = Edit->getParent().getVNInfoAt(Idx); if (!ParentVNI) { DEBUG(dbgs() << ": not live\n"); - return; + return Idx.getNextSlot(); } - DEBUG(dbgs() << ": valno " << ParentVNI->id); + DEBUG(dbgs() << ": valno " << ParentVNI->id << '\n'); + + MachineInstr *MI = LIS.getInstructionFromIndex(Idx); + assert(MI && "No instruction at index"); + VNInfo *VNI = defFromParent(0, ParentVNI, Idx, *MI->getParent(), + llvm::next(MachineBasicBlock::iterator(MI))); + return VNI->def; +} - MachineBasicBlock::iterator MII = lis_.getInstructionFromIndex(Idx); - VNInfo *VNI = defFromParent(dupli_, ParentVNI, Idx, - *MII->getParent(), llvm::next(MII)); +SlotIndex SplitEditor::leaveIntvBefore(SlotIndex Idx) { + assert(OpenIdx && "openIntv not called before leaveIntvBefore"); + DEBUG(dbgs() << " leaveIntvBefore " << Idx); - // Make sure that openli is properly extended from Idx to the new copy. - // FIXME: This shouldn't be necessary for remats. - openli_.addSimpleRange(Idx, VNI->def, ParentVNI); + // The interval must be live into the instruction at Idx. + Idx = Idx.getBoundaryIndex(); + VNInfo *ParentVNI = Edit->getParent().getVNInfoAt(Idx); + if (!ParentVNI) { + DEBUG(dbgs() << ": not live\n"); + return Idx.getNextSlot(); + } + DEBUG(dbgs() << ": valno " << ParentVNI->id << '\n'); - DEBUG(dbgs() << ": " << *openli_.getLI() << '\n'); + MachineInstr *MI = LIS.getInstructionFromIndex(Idx); + assert(MI && "No instruction at index"); + VNInfo *VNI = defFromParent(0, ParentVNI, Idx, *MI->getParent(), MI); + return VNI->def; } -/// leaveIntvAtTop - Leave the interval at the top of MBB. -/// Currently, only one value can leave the interval. -void SplitEditor::leaveIntvAtTop(MachineBasicBlock &MBB) { - assert(openli_.getLI() && "openIntv not called before leaveIntvAtTop"); - SlotIndex Start = lis_.getMBBStartIdx(&MBB); +SlotIndex SplitEditor::leaveIntvAtTop(MachineBasicBlock &MBB) { + assert(OpenIdx && "openIntv not called before leaveIntvAtTop"); + SlotIndex Start = LIS.getMBBStartIdx(&MBB); DEBUG(dbgs() << " leaveIntvAtTop BB#" << MBB.getNumber() << ", " << Start); - VNInfo *ParentVNI = edit_.getParent().getVNInfoAt(Start); + VNInfo *ParentVNI = Edit->getParent().getVNInfoAt(Start); if (!ParentVNI) { DEBUG(dbgs() << ": not live\n"); - return; + return Start; } - VNInfo *VNI = defFromParent(dupli_, ParentVNI, Start, MBB, + VNInfo *VNI = defFromParent(0, ParentVNI, Start, MBB, MBB.SkipPHIsAndLabels(MBB.begin())); + RegAssign.insert(Start, VNI->def, OpenIdx); + DEBUG(dump()); + return VNI->def; +} - // Finally we must make sure that openli is properly extended from Start to - // the new copy. - openli_.addSimpleRange(Start, VNI->def, ParentVNI); - DEBUG(dbgs() << ": " << *openli_.getLI() << '\n'); +void SplitEditor::overlapIntv(SlotIndex Start, SlotIndex End) { + assert(OpenIdx && "openIntv not called before overlapIntv"); + const VNInfo *ParentVNI = Edit->getParent().getVNInfoAt(Start); + assert(ParentVNI == Edit->getParent().getVNInfoAt(End.getPrevSlot()) && + "Parent changes value in extended range"); + assert(LIS.getMBBFromIndex(Start) == LIS.getMBBFromIndex(End) && + "Range cannot span basic blocks"); + + // The complement interval will be extended as needed by extendRange(). + markComplexMapped(0, ParentVNI); + DEBUG(dbgs() << " overlapIntv [" << Start << ';' << End << "):"); + RegAssign.insert(Start, End, OpenIdx); + DEBUG(dump()); } /// closeIntv - Indicate that we are done editing the currently open /// LiveInterval, and ranges can be trimmed. void SplitEditor::closeIntv() { - assert(openli_.getLI() && "openIntv not called before closeIntv"); - - DEBUG(dbgs() << " closeIntv cleaning up\n"); - DEBUG(dbgs() << " open " << *openli_.getLI() << '\n'); - openli_.reset(0); + assert(OpenIdx && "openIntv not called before closeIntv"); + OpenIdx = 0; +} + +/// transferSimpleValues - Transfer all simply defined values to the new live +/// ranges. +/// Values that were rematerialized or that have multiple defs are left alone. +bool SplitEditor::transferSimpleValues() { + bool Skipped = false; + RegAssignMap::const_iterator AssignI = RegAssign.begin(); + for (LiveInterval::const_iterator ParentI = Edit->getParent().begin(), + ParentE = Edit->getParent().end(); ParentI != ParentE; ++ParentI) { + DEBUG(dbgs() << " blit " << *ParentI << ':'); + VNInfo *ParentVNI = ParentI->valno; + // RegAssign has holes where RegIdx 0 should be used. + SlotIndex Start = ParentI->start; + AssignI.advanceTo(Start); + do { + unsigned RegIdx; + SlotIndex End = ParentI->end; + if (!AssignI.valid()) { + RegIdx = 0; + } else if (AssignI.start() <= Start) { + RegIdx = AssignI.value(); + if (AssignI.stop() < End) { + End = AssignI.stop(); + ++AssignI; + } + } else { + RegIdx = 0; + End = std::min(End, AssignI.start()); + } + DEBUG(dbgs() << " [" << Start << ';' << End << ")=" << RegIdx); + if (VNInfo *VNI = Values.lookup(std::make_pair(RegIdx, ParentVNI->id))) { + DEBUG(dbgs() << ':' << VNI->id); + Edit->get(RegIdx)->addRange(LiveRange(Start, End, VNI)); + } else + Skipped = true; + Start = End; + } while (Start != ParentI->end); + DEBUG(dbgs() << '\n'); + } + return Skipped; +} + +void SplitEditor::extendPHIKillRanges() { + // Extend live ranges to be live-out for successor PHI values. + for (LiveInterval::const_vni_iterator I = Edit->getParent().vni_begin(), + E = Edit->getParent().vni_end(); I != E; ++I) { + const VNInfo *PHIVNI = *I; + if (PHIVNI->isUnused() || !PHIVNI->isPHIDef()) + continue; + unsigned RegIdx = RegAssign.lookup(PHIVNI->def); + MachineBasicBlock *MBB = LIS.getMBBFromIndex(PHIVNI->def); + for (MachineBasicBlock::pred_iterator PI = MBB->pred_begin(), + PE = MBB->pred_end(); PI != PE; ++PI) { + SlotIndex End = LIS.getMBBEndIdx(*PI).getPrevSlot(); + // The predecessor may not have a live-out value. That is OK, like an + // undef PHI operand. + if (Edit->getParent().liveAt(End)) { + assert(RegAssign.lookup(End) == RegIdx && + "Different register assignment in phi predecessor"); + extendRange(RegIdx, End); + } + } + } } -/// rewrite - Rewrite all uses of reg to use the new registers. -void SplitEditor::rewrite(unsigned reg) { - for (MachineRegisterInfo::reg_iterator RI = mri_.reg_begin(reg), - RE = mri_.reg_end(); RI != RE;) { +/// rewriteAssigned - Rewrite all uses of Edit->getReg(). +void SplitEditor::rewriteAssigned(bool ExtendRanges) { + for (MachineRegisterInfo::reg_iterator RI = MRI.reg_begin(Edit->getReg()), + RE = MRI.reg_end(); RI != RE;) { MachineOperand &MO = RI.getOperand(); - unsigned OpNum = RI.getOperandNo(); MachineInstr *MI = MO.getParent(); ++RI; + // LiveDebugVariables should have handled all DBG_VALUE instructions. if (MI->isDebugValue()) { DEBUG(dbgs() << "Zapping " << *MI); - // FIXME: We can do much better with debug values. MO.setReg(0); continue; } - SlotIndex Idx = lis_.getInstructionIndex(MI); - Idx = MO.isUse() ? Idx.getUseIndex() : Idx.getDefIndex(); - LiveInterval *LI = 0; - for (LiveRangeEdit::iterator I = edit_.begin(), E = edit_.end(); I != E; - ++I) { - LiveInterval *testli = *I; - if (testli->liveAt(Idx)) { - LI = testli; - break; - } + + // operands don't really read the register, so just assign them to + // the complement. + if (MO.isUse() && MO.isUndef()) { + MO.setReg(Edit->get(0)->reg); + continue; } - DEBUG(dbgs() << " rewr BB#" << MI->getParent()->getNumber() << '\t'<< Idx); - assert(LI && "No register was live at use"); - MO.setReg(LI->reg); - if (MO.isUse() && !MI->isRegTiedToDefOperand(OpNum)) - MO.setIsKill(LI->killedAt(Idx.getDefIndex())); - DEBUG(dbgs() << '\t' << *MI); - } -} -void -SplitEditor::addTruncSimpleRange(SlotIndex Start, SlotIndex End, VNInfo *VNI) { - // Build vector of iterator pairs from the intervals. - typedef std::pair IIPair; - SmallVector Iters; - for (LiveRangeEdit::iterator LI = edit_.begin(), LE = edit_.end(); LI != LE; - ++LI) { - if (*LI == dupli_.getLI()) + SlotIndex Idx = LIS.getInstructionIndex(MI); + if (MO.isDef()) + Idx = MO.isEarlyClobber() ? Idx.getUseIndex() : Idx.getDefIndex(); + + // Rewrite to the mapped register at Idx. + unsigned RegIdx = RegAssign.lookup(Idx); + MO.setReg(Edit->get(RegIdx)->reg); + DEBUG(dbgs() << " rewr BB#" << MI->getParent()->getNumber() << '\t' + << Idx << ':' << RegIdx << '\t' << *MI); + + // Extend liveness to Idx if the instruction reads reg. + if (!ExtendRanges) continue; - LiveInterval::const_iterator I = (*LI)->find(Start); - LiveInterval::const_iterator E = (*LI)->end(); - if (I != E) - Iters.push_back(std::make_pair(I, E)); - } - SlotIndex sidx = Start; - // Break [Start;End) into segments that don't overlap any intervals. - for (;;) { - SlotIndex next = sidx, eidx = End; - // Find overlapping intervals. - for (unsigned i = 0; i != Iters.size() && sidx < eidx; ++i) { - LiveInterval::const_iterator I = Iters[i].first; - // Interval I is overlapping [sidx;eidx). Trim sidx. - if (I->start <= sidx) { - sidx = I->end; - // Move to the next run, remove iters when all are consumed. - I = ++Iters[i].first; - if (I == Iters[i].second) { - Iters.erase(Iters.begin() + i); - --i; - continue; - } - } - // Trim eidx too if needed. - if (I->start >= eidx) + // Skip instructions that don't read Reg. + if (MO.isDef()) { + if (!MO.getSubReg() && !MO.isEarlyClobber()) continue; - eidx = I->start; - next = I->end; - } - // Now, [sidx;eidx) doesn't overlap anything in intervals_. - if (sidx < eidx) - dupli_.addSimpleRange(sidx, eidx, VNI); - // If the interval end was truncated, we can try again from next. - if (next <= sidx) - break; - sidx = next; + // We may wan't to extend a live range for a partial redef, or for a use + // tied to an early clobber. + Idx = Idx.getPrevSlot(); + if (!Edit->getParent().liveAt(Idx)) + continue; + } else + Idx = Idx.getUseIndex(); + + extendRange(RegIdx, Idx); } } -void SplitEditor::computeRemainder() { - // First we need to fill in the live ranges in dupli. - // If values were redefined, we need a full recoloring with SSA update. - // If values were truncated, we only need to truncate the ranges. - // If values were partially rematted, we should shrink to uses. - // If values were fully rematted, they should be omitted. - // FIXME: If a single value is redefined, just move the def and truncate. - LiveInterval &parent = edit_.getParent(); - - // Values that are fully contained in the split intervals. - SmallPtrSet deadValues; - // Map all curli values that should have live defs in dupli. - for (LiveInterval::const_vni_iterator I = parent.vni_begin(), - E = parent.vni_end(); I != E; ++I) { - const VNInfo *VNI = *I; - // Don't transfer unused values to the new intervals. - if (VNI->isUnused()) - continue; - // Original def is contained in the split intervals. - if (intervalsLiveAt(VNI->def)) { - // Did this value escape? - if (dupli_.isMapped(VNI)) - truncatedValues.insert(VNI); - else - deadValues.insert(VNI); - continue; - } - // Add minimal live range at the definition. - VNInfo *DVNI = dupli_.defValue(VNI, VNI->def); - dupli_.getLI()->addRange(LiveRange(VNI->def, VNI->def.getNextSlot(), DVNI)); - } +void SplitEditor::deleteRematVictims() { + SmallVector Dead; + for (LiveRangeEdit::iterator I = Edit->begin(), E = Edit->end(); I != E; ++I){ + LiveInterval *LI = *I; + for (LiveInterval::const_iterator LII = LI->begin(), LIE = LI->end(); + LII != LIE; ++LII) { + // Dead defs end at the store slot. + if (LII->end != LII->valno->def.getNextSlot()) + continue; + MachineInstr *MI = LIS.getInstructionFromIndex(LII->valno->def); + assert(MI && "Missing instruction for dead def"); + MI->addRegisterDead(LI->reg, &TRI); - // Add all ranges to dupli. - for (LiveInterval::const_iterator I = parent.begin(), E = parent.end(); - I != E; ++I) { - const LiveRange &LR = *I; - if (truncatedValues.count(LR.valno)) { - // recolor after removing intervals_. - addTruncSimpleRange(LR.start, LR.end, LR.valno); - } else if (!deadValues.count(LR.valno)) { - // recolor without truncation. - dupli_.addSimpleRange(LR.start, LR.end, LR.valno); + if (!MI->allDefsAreDead()) + continue; + + DEBUG(dbgs() << "All defs dead: " << *MI); + Dead.push_back(MI); } } - // Extend dupli_ to be live out of any critical loop predecessors. - // This means we have multiple registers live out of those blocks. - // The alternative would be to split the critical edges. - if (criticalPreds_.empty()) + if (Dead.empty()) return; - for (SplitAnalysis::BlockPtrSet::iterator I = criticalPreds_.begin(), - E = criticalPreds_.end(); I != E; ++I) - dupli_.extendTo(*I, lis_.getMBBEndIdx(*I).getPrevSlot()); - criticalPreds_.clear(); + + Edit->eliminateDeadDefs(Dead, LIS, VRM, TII); } void SplitEditor::finish() { - assert(!openli_.getLI() && "Previous LI not closed before rewrite"); - assert(dupli_.getLI() && "No dupli for rewrite. Noop spilt?"); + assert(OpenIdx == 0 && "Previous LI not closed before rewrite"); + ++NumFinished; - // Complete dupli liveness. - computeRemainder(); + // At this point, the live intervals in Edit contain VNInfos corresponding to + // the inserted copies. - // Get rid of unused values and set phi-kill flags. - for (LiveRangeEdit::iterator I = edit_.begin(), E = edit_.end(); I != E; ++I) - (*I)->RenumberValues(lis_); + // Add the original defs from the parent interval. + for (LiveInterval::const_vni_iterator I = Edit->getParent().vni_begin(), + E = Edit->getParent().vni_end(); I != E; ++I) { + const VNInfo *ParentVNI = *I; + if (ParentVNI->isUnused()) + continue; + unsigned RegIdx = RegAssign.lookup(ParentVNI->def); + VNInfo *VNI = defValue(RegIdx, ParentVNI, ParentVNI->def); + VNI->setIsPHIDef(ParentVNI->isPHIDef()); + VNI->setCopy(ParentVNI->getCopy()); + + // Mark rematted values as complex everywhere to force liveness computation. + // The new live ranges may be truncated. + if (Edit->didRematerialize(ParentVNI)) + for (unsigned i = 0, e = Edit->size(); i != e; ++i) + markComplexMapped(i, ParentVNI); + } + +#ifndef NDEBUG + // Every new interval must have a def by now, otherwise the split is bogus. + for (LiveRangeEdit::iterator I = Edit->begin(), E = Edit->end(); I != E; ++I) + assert((*I)->hasAtLeastOneValue() && "Split interval has no value"); +#endif + + // Transfer the simply mapped values, check if any are complex. + bool Complex = transferSimpleValues(); + if (Complex) + extendPHIKillRanges(); + else + ++NumSimple; + + // Rewrite virtual registers, possibly extending ranges. + rewriteAssigned(Complex); - // Rewrite instructions. - rewrite(edit_.getReg()); + // Delete defs that were rematted everywhere. + if (Complex) + deleteRematVictims(); + + // Get rid of unused values and set phi-kill flags. + for (LiveRangeEdit::iterator I = Edit->begin(), E = Edit->end(); I != E; ++I) + (*I)->RenumberValues(LIS); // Now check if any registers were separated into multiple components. - ConnectedVNInfoEqClasses ConEQ(lis_); - for (unsigned i = 0, e = edit_.size(); i != e; ++i) { + ConnectedVNInfoEqClasses ConEQ(LIS); + for (unsigned i = 0, e = Edit->size(); i != e; ++i) { // Don't use iterators, they are invalidated by create() below. - LiveInterval *li = edit_.get(i); + LiveInterval *li = Edit->get(i); unsigned NumComp = ConEQ.Classify(li); if (NumComp <= 1) continue; @@ -1039,215 +875,68 @@ void SplitEditor::finish() { SmallVector dups; dups.push_back(li); for (unsigned i = 1; i != NumComp; ++i) - dups.push_back(&edit_.create(mri_, lis_, vrm_)); - ConEQ.Distribute(&dups[0]); - // Rewrite uses to the new regs. - rewrite(li->reg); + dups.push_back(&Edit->create(LIS, VRM)); + ConEQ.Distribute(&dups[0], MRI); } // Calculate spill weight and allocation hints for new intervals. - VirtRegAuxInfo vrai(vrm_.getMachineFunction(), lis_, sa_.loops_); - for (LiveRangeEdit::iterator I = edit_.begin(), E = edit_.end(); I != E; ++I){ + VirtRegAuxInfo vrai(VRM.getMachineFunction(), LIS, SA.Loops); + for (LiveRangeEdit::iterator I = Edit->begin(), E = Edit->end(); I != E; ++I){ LiveInterval &li = **I; vrai.CalculateRegClass(li.reg); vrai.CalculateWeightAndHint(li); - DEBUG(dbgs() << " new interval " << mri_.getRegClass(li.reg)->getName() + DEBUG(dbgs() << " new interval " << MRI.getRegClass(li.reg)->getName() << ":" << li << '\n'); } } -//===----------------------------------------------------------------------===// -// Loop Splitting -//===----------------------------------------------------------------------===// - -void SplitEditor::splitAroundLoop(const MachineLoop *Loop) { - SplitAnalysis::LoopBlocks Blocks; - sa_.getLoopBlocks(Loop, Blocks); - - DEBUG({ - dbgs() << " splitAround"; sa_.print(Blocks, dbgs()); dbgs() << '\n'; - }); - - // Break critical edges as needed. - SplitAnalysis::BlockPtrSet CriticalExits; - sa_.getCriticalExits(Blocks, CriticalExits); - assert(CriticalExits.empty() && "Cannot break critical exits yet"); - - // Get critical predecessors so computeRemainder can deal with them. - sa_.getCriticalPreds(Blocks, criticalPreds_); - - // Create new live interval for the loop. - openIntv(); - - // Insert copies in the predecessors if live-in to the header. - if (lis_.isLiveInToMBB(edit_.getParent(), Loop->getHeader())) { - for (SplitAnalysis::BlockPtrSet::iterator I = Blocks.Preds.begin(), - E = Blocks.Preds.end(); I != E; ++I) { - MachineBasicBlock &MBB = const_cast(**I); - enterIntvAtEnd(MBB); - } - } - - // Switch all loop blocks. - for (SplitAnalysis::BlockPtrSet::iterator I = Blocks.Loop.begin(), - E = Blocks.Loop.end(); I != E; ++I) - useIntv(**I); - - // Insert back copies in the exit blocks. - for (SplitAnalysis::BlockPtrSet::iterator I = Blocks.Exits.begin(), - E = Blocks.Exits.end(); I != E; ++I) { - MachineBasicBlock &MBB = const_cast(**I); - leaveIntvAtTop(MBB); - } - - // Done. - closeIntv(); - finish(); -} - - //===----------------------------------------------------------------------===// // Single Block Splitting //===----------------------------------------------------------------------===// -/// getMultiUseBlocks - if curli has more than one use in a basic block, it -/// may be an advantage to split curli for the duration of the block. +/// getMultiUseBlocks - if CurLI has more than one use in a basic block, it +/// may be an advantage to split CurLI for the duration of the block. bool SplitAnalysis::getMultiUseBlocks(BlockPtrSet &Blocks) { - // If curli is local to one block, there is no point to splitting it. - if (usingBlocks_.size() <= 1) + // If CurLI is local to one block, there is no point to splitting it. + if (LiveBlocks.size() <= 1) return false; // Add blocks with multiple uses. - for (BlockCountMap::iterator I = usingBlocks_.begin(), E = usingBlocks_.end(); - I != E; ++I) - switch (I->second) { - case 0: - case 1: + for (unsigned i = 0, e = LiveBlocks.size(); i != e; ++i) { + const BlockInfo &BI = LiveBlocks[i]; + if (!BI.Uses) continue; - case 2: { - // When there are only two uses and curli is both live in and live out, - // we don't really win anything by isolating the block since we would be - // inserting two copies. - // The remaing register would still have two uses in the block. (Unless it - // separates into disconnected components). - if (lis_.isLiveInToMBB(*curli_, I->first) && - lis_.isLiveOutOfMBB(*curli_, I->first)) - continue; - } // Fall through. - default: - Blocks.insert(I->first); - } + unsigned Instrs = UsingBlocks.lookup(BI.MBB); + if (Instrs <= 1) + continue; + if (Instrs == 2 && BI.LiveIn && BI.LiveOut && !BI.LiveThrough) + continue; + Blocks.insert(BI.MBB); + } return !Blocks.empty(); } -/// splitSingleBlocks - Split curli into a separate live interval inside each +/// splitSingleBlocks - Split CurLI into a separate live interval inside each /// basic block in Blocks. void SplitEditor::splitSingleBlocks(const SplitAnalysis::BlockPtrSet &Blocks) { DEBUG(dbgs() << " splitSingleBlocks for " << Blocks.size() << " blocks.\n"); - // Determine the first and last instruction using curli in each block. - typedef std::pair IndexPair; - typedef DenseMap IndexPairMap; - IndexPairMap MBBRange; - for (SplitAnalysis::InstrPtrSet::const_iterator I = sa_.usingInstrs_.begin(), - E = sa_.usingInstrs_.end(); I != E; ++I) { - const MachineBasicBlock *MBB = (*I)->getParent(); - if (!Blocks.count(MBB)) - continue; - SlotIndex Idx = lis_.getInstructionIndex(*I); - DEBUG(dbgs() << " BB#" << MBB->getNumber() << '\t' << Idx << '\t' << **I); - IndexPair &IP = MBBRange[MBB]; - if (!IP.first.isValid() || Idx < IP.first) - IP.first = Idx; - if (!IP.second.isValid() || Idx > IP.second) - IP.second = Idx; - } - // Create a new interval for each block. - for (SplitAnalysis::BlockPtrSet::const_iterator I = Blocks.begin(), - E = Blocks.end(); I != E; ++I) { - IndexPair &IP = MBBRange[*I]; - DEBUG(dbgs() << " splitting for BB#" << (*I)->getNumber() << ": [" - << IP.first << ';' << IP.second << ")\n"); - assert(IP.first.isValid() && IP.second.isValid()); - - openIntv(); - enterIntvBefore(IP.first); - useIntv(IP.first.getBaseIndex(), IP.second.getBoundaryIndex()); - leaveIntvAfter(IP.second); - closeIntv(); - } - finish(); -} - - -//===----------------------------------------------------------------------===// -// Sub Block Splitting -//===----------------------------------------------------------------------===// - -/// getBlockForInsideSplit - If curli is contained inside a single basic block, -/// and it wou pay to subdivide the interval inside that block, return it. -/// Otherwise return NULL. The returned block can be passed to -/// SplitEditor::splitInsideBlock. -const MachineBasicBlock *SplitAnalysis::getBlockForInsideSplit() { - // The interval must be exclusive to one block. - if (usingBlocks_.size() != 1) - return 0; - // Don't to this for less than 4 instructions. We want to be sure that - // splitting actually reduces the instruction count per interval. - if (usingInstrs_.size() < 4) - return 0; - return usingBlocks_.begin()->first; -} - -/// splitInsideBlock - Split curli into multiple intervals inside MBB. -void SplitEditor::splitInsideBlock(const MachineBasicBlock *MBB) { - SmallVector Uses; - Uses.reserve(sa_.usingInstrs_.size()); - for (SplitAnalysis::InstrPtrSet::const_iterator I = sa_.usingInstrs_.begin(), - E = sa_.usingInstrs_.end(); I != E; ++I) - if ((*I)->getParent() == MBB) - Uses.push_back(lis_.getInstructionIndex(*I)); - DEBUG(dbgs() << " splitInsideBlock BB#" << MBB->getNumber() << " for " - << Uses.size() << " instructions.\n"); - assert(Uses.size() >= 3 && "Need at least 3 instructions"); - array_pod_sort(Uses.begin(), Uses.end()); - - // Simple algorithm: Find the largest gap between uses as determined by slot - // indices. Create new intervals for instructions before the gap and after the - // gap. - unsigned bestPos = 0; - int bestGap = 0; - DEBUG(dbgs() << " dist (" << Uses[0]); - for (unsigned i = 1, e = Uses.size(); i != e; ++i) { - int g = Uses[i-1].distance(Uses[i]); - DEBUG(dbgs() << ") -" << g << "- (" << Uses[i]); - if (g > bestGap) - bestPos = i, bestGap = g; - } - DEBUG(dbgs() << "), best: -" << bestGap << "-\n"); - - // bestPos points to the first use after the best gap. - assert(bestPos > 0 && "Invalid gap"); - - // FIXME: Don't create intervals for low densities. - - // First interval before the gap. Don't create single-instr intervals. - if (bestPos > 1) { - openIntv(); - enterIntvBefore(Uses.front()); - useIntv(Uses.front().getBaseIndex(), Uses[bestPos-1].getBoundaryIndex()); - leaveIntvAfter(Uses[bestPos-1]); - closeIntv(); - } + for (unsigned i = 0, e = SA.LiveBlocks.size(); i != e; ++i) { + const SplitAnalysis::BlockInfo &BI = SA.LiveBlocks[i]; + if (!BI.Uses || !Blocks.count(BI.MBB)) + continue; - // Second interval after the gap. - if (bestPos < Uses.size()-1) { openIntv(); - enterIntvBefore(Uses[bestPos]); - useIntv(Uses[bestPos].getBaseIndex(), Uses.back().getBoundaryIndex()); - leaveIntvAfter(Uses.back()); + SlotIndex SegStart = enterIntvBefore(BI.FirstUse); + if (!BI.LiveOut || BI.LastUse < BI.LastSplitPoint) { + useIntv(SegStart, leaveIntvAfter(BI.LastUse)); + } else { + // The last use is after the last valid split point. + SlotIndex SegStop = leaveIntvBefore(BI.LastSplitPoint); + useIntv(SegStart, SegStop); + overlapIntv(SegStop, BI.LastUse); + } closeIntv(); } - finish(); }