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Diffstat (limited to 'llvm/lib/CodeGen/LiveIntervals.cpp')
| -rw-r--r-- | llvm/lib/CodeGen/LiveIntervals.cpp | 1598 |
1 files changed, 1598 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/LiveIntervals.cpp b/llvm/lib/CodeGen/LiveIntervals.cpp new file mode 100644 index 00000000000..79fdba7e062 --- /dev/null +++ b/llvm/lib/CodeGen/LiveIntervals.cpp @@ -0,0 +1,1598 @@ +//===- LiveIntervals.cpp - Live Interval Analysis -------------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +/// \file This file implements the LiveInterval analysis pass which is used +/// by the Linear Scan Register allocator. This pass linearizes the +/// basic blocks of the function in DFS order and computes live intervals for +/// each virtual and physical register. +// +//===----------------------------------------------------------------------===// + +#include "llvm/CodeGen/LiveIntervals.h" +#include "LiveRangeCalc.h" +#include "llvm/ADT/ArrayRef.h" +#include "llvm/ADT/DepthFirstIterator.h" +#include "llvm/ADT/SmallPtrSet.h" +#include "llvm/ADT/SmallVector.h" +#include "llvm/ADT/iterator_range.h" +#include "llvm/Analysis/AliasAnalysis.h" +#include "llvm/CodeGen/LiveInterval.h" +#include "llvm/CodeGen/LiveVariables.h" +#include "llvm/CodeGen/MachineBasicBlock.h" +#include "llvm/CodeGen/MachineBlockFrequencyInfo.h" +#include "llvm/CodeGen/MachineDominators.h" +#include "llvm/CodeGen/MachineFunction.h" +#include "llvm/CodeGen/MachineInstr.h" +#include "llvm/CodeGen/MachineInstrBundle.h" +#include "llvm/CodeGen/MachineOperand.h" +#include "llvm/CodeGen/MachineRegisterInfo.h" +#include "llvm/CodeGen/Passes.h" +#include "llvm/CodeGen/SlotIndexes.h" +#include "llvm/CodeGen/TargetRegisterInfo.h" +#include "llvm/CodeGen/TargetSubtargetInfo.h" +#include "llvm/CodeGen/VirtRegMap.h" +#include "llvm/MC/LaneBitmask.h" +#include "llvm/MC/MCRegisterInfo.h" +#include "llvm/Pass.h" +#include "llvm/Support/BlockFrequency.h" +#include "llvm/Support/CommandLine.h" +#include "llvm/Support/Compiler.h" +#include "llvm/Support/Debug.h" +#include "llvm/Support/MathExtras.h" +#include "llvm/Support/raw_ostream.h" +#include <algorithm> +#include <cassert> +#include <cstdint> +#include <iterator> +#include <tuple> +#include <utility> + +using namespace llvm; + +#define DEBUG_TYPE "regalloc" + +char LiveIntervals::ID = 0; +char &llvm::LiveIntervalsID = LiveIntervals::ID; +INITIALIZE_PASS_BEGIN(LiveIntervals, "liveintervals", + "Live Interval Analysis", false, false) +INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass) +INITIALIZE_PASS_DEPENDENCY(MachineDominatorTree) +INITIALIZE_PASS_DEPENDENCY(SlotIndexes) +INITIALIZE_PASS_END(LiveIntervals, "liveintervals", + "Live Interval Analysis", false, false) + +#ifndef NDEBUG +static cl::opt<bool> EnablePrecomputePhysRegs( + "precompute-phys-liveness", cl::Hidden, + cl::desc("Eagerly compute live intervals for all physreg units.")); +#else +static bool EnablePrecomputePhysRegs = false; +#endif // NDEBUG + +namespace llvm { + +cl::opt<bool> UseSegmentSetForPhysRegs( + "use-segment-set-for-physregs", cl::Hidden, cl::init(true), + cl::desc( + "Use segment set for the computation of the live ranges of physregs.")); + +} // end namespace llvm + +void LiveIntervals::getAnalysisUsage(AnalysisUsage &AU) const { + AU.setPreservesCFG(); + AU.addRequired<AAResultsWrapperPass>(); + AU.addPreserved<AAResultsWrapperPass>(); + AU.addPreserved<LiveVariables>(); + AU.addPreservedID(MachineLoopInfoID); + AU.addRequiredTransitiveID(MachineDominatorsID); + AU.addPreservedID(MachineDominatorsID); + AU.addPreserved<SlotIndexes>(); + AU.addRequiredTransitive<SlotIndexes>(); + MachineFunctionPass::getAnalysisUsage(AU); +} + +LiveIntervals::LiveIntervals() : MachineFunctionPass(ID) { + initializeLiveIntervalsPass(*PassRegistry::getPassRegistry()); +} + +LiveIntervals::~LiveIntervals() { + delete LRCalc; +} + +void LiveIntervals::releaseMemory() { + // Free the live intervals themselves. + for (unsigned i = 0, e = VirtRegIntervals.size(); i != e; ++i) + delete VirtRegIntervals[TargetRegisterInfo::index2VirtReg(i)]; + VirtRegIntervals.clear(); + RegMaskSlots.clear(); + RegMaskBits.clear(); + RegMaskBlocks.clear(); + + for (LiveRange *LR : RegUnitRanges) + delete LR; + RegUnitRanges.clear(); + + // Release VNInfo memory regions, VNInfo objects don't need to be dtor'd. + VNInfoAllocator.Reset(); +} + +bool LiveIntervals::runOnMachineFunction(MachineFunction &fn) { + MF = &fn; + MRI = &MF->getRegInfo(); + TRI = MF->getSubtarget().getRegisterInfo(); + TII = MF->getSubtarget().getInstrInfo(); + AA = &getAnalysis<AAResultsWrapperPass>().getAAResults(); + Indexes = &getAnalysis<SlotIndexes>(); + DomTree = &getAnalysis<MachineDominatorTree>(); + + if (!LRCalc) + LRCalc = new LiveRangeCalc(); + + // Allocate space for all virtual registers. + VirtRegIntervals.resize(MRI->getNumVirtRegs()); + + computeVirtRegs(); + computeRegMasks(); + computeLiveInRegUnits(); + + if (EnablePrecomputePhysRegs) { + // For stress testing, precompute live ranges of all physical register + // units, including reserved registers. + for (unsigned i = 0, e = TRI->getNumRegUnits(); i != e; ++i) + getRegUnit(i); + } + DEBUG(dump()); + return true; +} + +void LiveIntervals::print(raw_ostream &OS, const Module* ) const { + OS << "********** INTERVALS **********\n"; + + // Dump the regunits. + for (unsigned Unit = 0, UnitE = RegUnitRanges.size(); Unit != UnitE; ++Unit) + if (LiveRange *LR = RegUnitRanges[Unit]) + OS << printRegUnit(Unit, TRI) << ' ' << *LR << '\n'; + + // Dump the virtregs. + for (unsigned i = 0, e = MRI->getNumVirtRegs(); i != e; ++i) { + unsigned Reg = TargetRegisterInfo::index2VirtReg(i); + if (hasInterval(Reg)) + OS << getInterval(Reg) << '\n'; + } + + OS << "RegMasks:"; + for (SlotIndex Idx : RegMaskSlots) + OS << ' ' << Idx; + OS << '\n'; + + printInstrs(OS); +} + +void LiveIntervals::printInstrs(raw_ostream &OS) const { + OS << "********** MACHINEINSTRS **********\n"; + MF->print(OS, Indexes); +} + +#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) +LLVM_DUMP_METHOD void LiveIntervals::dumpInstrs() const { + printInstrs(dbgs()); +} +#endif + +LiveInterval* LiveIntervals::createInterval(unsigned reg) { + float Weight = TargetRegisterInfo::isPhysicalRegister(reg) ? huge_valf : 0.0F; + return new LiveInterval(reg, Weight); +} + +/// Compute the live interval of a virtual register, based on defs and uses. +void LiveIntervals::computeVirtRegInterval(LiveInterval &LI) { + assert(LRCalc && "LRCalc not initialized."); + assert(LI.empty() && "Should only compute empty intervals."); + LRCalc->reset(MF, getSlotIndexes(), DomTree, &getVNInfoAllocator()); + LRCalc->calculate(LI, MRI->shouldTrackSubRegLiveness(LI.reg)); + computeDeadValues(LI, nullptr); +} + +void LiveIntervals::computeVirtRegs() { + for (unsigned i = 0, e = MRI->getNumVirtRegs(); i != e; ++i) { + unsigned Reg = TargetRegisterInfo::index2VirtReg(i); + if (MRI->reg_nodbg_empty(Reg)) + continue; + createAndComputeVirtRegInterval(Reg); + } +} + +void LiveIntervals::computeRegMasks() { + RegMaskBlocks.resize(MF->getNumBlockIDs()); + + // Find all instructions with regmask operands. + for (const MachineBasicBlock &MBB : *MF) { + std::pair<unsigned, unsigned> &RMB = RegMaskBlocks[MBB.getNumber()]; + RMB.first = RegMaskSlots.size(); + + // Some block starts, such as EH funclets, create masks. + if (const uint32_t *Mask = MBB.getBeginClobberMask(TRI)) { + RegMaskSlots.push_back(Indexes->getMBBStartIdx(&MBB)); + RegMaskBits.push_back(Mask); + } + + for (const MachineInstr &MI : MBB) { + for (const MachineOperand &MO : MI.operands()) { + if (!MO.isRegMask()) + continue; + RegMaskSlots.push_back(Indexes->getInstructionIndex(MI).getRegSlot()); + RegMaskBits.push_back(MO.getRegMask()); + } + } + + // Some block ends, such as funclet returns, create masks. Put the mask on + // the last instruction of the block, because MBB slot index intervals are + // half-open. + if (const uint32_t *Mask = MBB.getEndClobberMask(TRI)) { + assert(!MBB.empty() && "empty return block?"); + RegMaskSlots.push_back( + Indexes->getInstructionIndex(MBB.back()).getRegSlot()); + RegMaskBits.push_back(Mask); + } + + // Compute the number of register mask instructions in this block. + RMB.second = RegMaskSlots.size() - RMB.first; + } +} + +//===----------------------------------------------------------------------===// +// Register Unit Liveness +//===----------------------------------------------------------------------===// +// +// Fixed interference typically comes from ABI boundaries: Function arguments +// and return values are passed in fixed registers, and so are exception +// pointers entering landing pads. Certain instructions require values to be +// present in specific registers. That is also represented through fixed +// interference. +// + +/// Compute the live range of a register unit, based on the uses and defs of +/// aliasing registers. The range should be empty, or contain only dead +/// phi-defs from ABI blocks. +void LiveIntervals::computeRegUnitRange(LiveRange &LR, unsigned Unit) { + assert(LRCalc && "LRCalc not initialized."); + LRCalc->reset(MF, getSlotIndexes(), DomTree, &getVNInfoAllocator()); + + // The physregs aliasing Unit are the roots and their super-registers. + // Create all values as dead defs before extending to uses. Note that roots + // may share super-registers. That's OK because createDeadDefs() is + // idempotent. It is very rare for a register unit to have multiple roots, so + // uniquing super-registers is probably not worthwhile. + bool IsReserved = false; + for (MCRegUnitRootIterator Root(Unit, TRI); Root.isValid(); ++Root) { + bool IsRootReserved = true; + for (MCSuperRegIterator Super(*Root, TRI, /*IncludeSelf=*/true); + Super.isValid(); ++Super) { + unsigned Reg = *Super; + if (!MRI->reg_empty(Reg)) + LRCalc->createDeadDefs(LR, Reg); + // A register unit is considered reserved if all its roots and all their + // super registers are reserved. + if (!MRI->isReserved(Reg)) + IsRootReserved = false; + } + IsReserved |= IsRootReserved; + } + assert(IsReserved == MRI->isReservedRegUnit(Unit) && + "reserved computation mismatch"); + + // Now extend LR to reach all uses. + // Ignore uses of reserved registers. We only track defs of those. + if (!IsReserved) { + for (MCRegUnitRootIterator Root(Unit, TRI); Root.isValid(); ++Root) { + for (MCSuperRegIterator Super(*Root, TRI, /*IncludeSelf=*/true); + Super.isValid(); ++Super) { + unsigned Reg = *Super; + if (!MRI->reg_empty(Reg)) + LRCalc->extendToUses(LR, Reg); + } + } + } + + // Flush the segment set to the segment vector. + if (UseSegmentSetForPhysRegs) + LR.flushSegmentSet(); +} + +/// Precompute the live ranges of any register units that are live-in to an ABI +/// block somewhere. Register values can appear without a corresponding def when +/// entering the entry block or a landing pad. +void LiveIntervals::computeLiveInRegUnits() { + RegUnitRanges.resize(TRI->getNumRegUnits()); + DEBUG(dbgs() << "Computing live-in reg-units in ABI blocks.\n"); + + // Keep track of the live range sets allocated. + SmallVector<unsigned, 8> NewRanges; + + // Check all basic blocks for live-ins. + for (const MachineBasicBlock &MBB : *MF) { + // We only care about ABI blocks: Entry + landing pads. + if ((&MBB != &MF->front() && !MBB.isEHPad()) || MBB.livein_empty()) + continue; + + // Create phi-defs at Begin for all live-in registers. + SlotIndex Begin = Indexes->getMBBStartIdx(&MBB); + DEBUG(dbgs() << Begin << "\t" << printMBBReference(MBB)); + for (const auto &LI : MBB.liveins()) { + for (MCRegUnitIterator Units(LI.PhysReg, TRI); Units.isValid(); ++Units) { + unsigned Unit = *Units; + LiveRange *LR = RegUnitRanges[Unit]; + if (!LR) { + // Use segment set to speed-up initial computation of the live range. + LR = RegUnitRanges[Unit] = new LiveRange(UseSegmentSetForPhysRegs); + NewRanges.push_back(Unit); + } + VNInfo *VNI = LR->createDeadDef(Begin, getVNInfoAllocator()); + (void)VNI; + DEBUG(dbgs() << ' ' << printRegUnit(Unit, TRI) << '#' << VNI->id); + } + } + DEBUG(dbgs() << '\n'); + } + DEBUG(dbgs() << "Created " << NewRanges.size() << " new intervals.\n"); + + // Compute the 'normal' part of the ranges. + for (unsigned Unit : NewRanges) + computeRegUnitRange(*RegUnitRanges[Unit], Unit); +} + +static void createSegmentsForValues(LiveRange &LR, + iterator_range<LiveInterval::vni_iterator> VNIs) { + for (VNInfo *VNI : VNIs) { + if (VNI->isUnused()) + continue; + SlotIndex Def = VNI->def; + LR.addSegment(LiveRange::Segment(Def, Def.getDeadSlot(), VNI)); + } +} + +using ShrinkToUsesWorkList = SmallVector<std::pair<SlotIndex, VNInfo*>, 16>; + +static void extendSegmentsToUses(LiveRange &LR, const SlotIndexes &Indexes, + ShrinkToUsesWorkList &WorkList, + const LiveRange &OldRange) { + // Keep track of the PHIs that are in use. + SmallPtrSet<VNInfo*, 8> UsedPHIs; + // Blocks that have already been added to WorkList as live-out. + SmallPtrSet<const MachineBasicBlock*, 16> LiveOut; + + // Extend intervals to reach all uses in WorkList. + while (!WorkList.empty()) { + SlotIndex Idx = WorkList.back().first; + VNInfo *VNI = WorkList.back().second; + WorkList.pop_back(); + const MachineBasicBlock *MBB = Indexes.getMBBFromIndex(Idx.getPrevSlot()); + SlotIndex BlockStart = Indexes.getMBBStartIdx(MBB); + + // Extend the live range for VNI to be live at Idx. + if (VNInfo *ExtVNI = LR.extendInBlock(BlockStart, Idx)) { + assert(ExtVNI == VNI && "Unexpected existing value number"); + (void)ExtVNI; + // Is this a PHIDef we haven't seen before? + if (!VNI->isPHIDef() || VNI->def != BlockStart || + !UsedPHIs.insert(VNI).second) + continue; + // The PHI is live, make sure the predecessors are live-out. + for (const MachineBasicBlock *Pred : MBB->predecessors()) { + if (!LiveOut.insert(Pred).second) + continue; + SlotIndex Stop = Indexes.getMBBEndIdx(Pred); + // A predecessor is not required to have a live-out value for a PHI. + if (VNInfo *PVNI = OldRange.getVNInfoBefore(Stop)) + WorkList.push_back(std::make_pair(Stop, PVNI)); + } + continue; + } + + // VNI is live-in to MBB. + DEBUG(dbgs() << " live-in at " << BlockStart << '\n'); + LR.addSegment(LiveRange::Segment(BlockStart, Idx, VNI)); + + // Make sure VNI is live-out from the predecessors. + for (const MachineBasicBlock *Pred : MBB->predecessors()) { + if (!LiveOut.insert(Pred).second) + continue; + SlotIndex Stop = Indexes.getMBBEndIdx(Pred); + assert(OldRange.getVNInfoBefore(Stop) == VNI && + "Wrong value out of predecessor"); + WorkList.push_back(std::make_pair(Stop, VNI)); + } + } +} + +bool LiveIntervals::shrinkToUses(LiveInterval *li, + SmallVectorImpl<MachineInstr*> *dead) { + DEBUG(dbgs() << "Shrink: " << *li << '\n'); + assert(TargetRegisterInfo::isVirtualRegister(li->reg) + && "Can only shrink virtual registers"); + + // Shrink subregister live ranges. + bool NeedsCleanup = false; + for (LiveInterval::SubRange &S : li->subranges()) { + shrinkToUses(S, li->reg); + if (S.empty()) + NeedsCleanup = true; + } + if (NeedsCleanup) + li->removeEmptySubRanges(); + + // Find all the values used, including PHI kills. + ShrinkToUsesWorkList WorkList; + + // Visit all instructions reading li->reg. + unsigned Reg = li->reg; + for (MachineInstr &UseMI : MRI->reg_instructions(Reg)) { + if (UseMI.isDebugValue() || !UseMI.readsVirtualRegister(Reg)) + continue; + SlotIndex Idx = getInstructionIndex(UseMI).getRegSlot(); + LiveQueryResult LRQ = li->Query(Idx); + VNInfo *VNI = LRQ.valueIn(); + if (!VNI) { + // This shouldn't happen: readsVirtualRegister returns true, but there is + // no live value. It is likely caused by a target getting <undef> flags + // wrong. + DEBUG(dbgs() << Idx << '\t' << UseMI + << "Warning: Instr claims to read non-existent value in " + << *li << '\n'); + continue; + } + // Special case: An early-clobber tied operand reads and writes the + // register one slot early. + if (VNInfo *DefVNI = LRQ.valueDefined()) + Idx = DefVNI->def; + + WorkList.push_back(std::make_pair(Idx, VNI)); + } + + // Create new live ranges with only minimal live segments per def. + LiveRange NewLR; + createSegmentsForValues(NewLR, make_range(li->vni_begin(), li->vni_end())); + extendSegmentsToUses(NewLR, *Indexes, WorkList, *li); + + // Move the trimmed segments back. + li->segments.swap(NewLR.segments); + + // Handle dead values. + bool CanSeparate = computeDeadValues(*li, dead); + DEBUG(dbgs() << "Shrunk: " << *li << '\n'); + return CanSeparate; +} + +bool LiveIntervals::computeDeadValues(LiveInterval &LI, + SmallVectorImpl<MachineInstr*> *dead) { + bool MayHaveSplitComponents = false; + for (VNInfo *VNI : LI.valnos) { + if (VNI->isUnused()) + continue; + SlotIndex Def = VNI->def; + LiveRange::iterator I = LI.FindSegmentContaining(Def); + assert(I != LI.end() && "Missing segment for VNI"); + + // Is the register live before? Otherwise we may have to add a read-undef + // flag for subregister defs. + unsigned VReg = LI.reg; + if (MRI->shouldTrackSubRegLiveness(VReg)) { + if ((I == LI.begin() || std::prev(I)->end < Def) && !VNI->isPHIDef()) { + MachineInstr *MI = getInstructionFromIndex(Def); + MI->setRegisterDefReadUndef(VReg); + } + } + + if (I->end != Def.getDeadSlot()) + continue; + if (VNI->isPHIDef()) { + // This is a dead PHI. Remove it. + VNI->markUnused(); + LI.removeSegment(I); + DEBUG(dbgs() << "Dead PHI at " << Def << " may separate interval\n"); + MayHaveSplitComponents = true; + } else { + // This is a dead def. Make sure the instruction knows. + MachineInstr *MI = getInstructionFromIndex(Def); + assert(MI && "No instruction defining live value"); + MI->addRegisterDead(LI.reg, TRI); + if (dead && MI->allDefsAreDead()) { + DEBUG(dbgs() << "All defs dead: " << Def << '\t' << *MI); + dead->push_back(MI); + } + } + } + return MayHaveSplitComponents; +} + +void LiveIntervals::shrinkToUses(LiveInterval::SubRange &SR, unsigned Reg) { + DEBUG(dbgs() << "Shrink: " << SR << '\n'); + assert(TargetRegisterInfo::isVirtualRegister(Reg) + && "Can only shrink virtual registers"); + // Find all the values used, including PHI kills. + ShrinkToUsesWorkList WorkList; + + // Visit all instructions reading Reg. + SlotIndex LastIdx; + for (MachineOperand &MO : MRI->use_nodbg_operands(Reg)) { + // Skip "undef" uses. + if (!MO.readsReg()) + continue; + // Maybe the operand is for a subregister we don't care about. + unsigned SubReg = MO.getSubReg(); + if (SubReg != 0) { + LaneBitmask LaneMask = TRI->getSubRegIndexLaneMask(SubReg); + if ((LaneMask & SR.LaneMask).none()) + continue; + } + // We only need to visit each instruction once. + MachineInstr *UseMI = MO.getParent(); + SlotIndex Idx = getInstructionIndex(*UseMI).getRegSlot(); + if (Idx == LastIdx) + continue; + LastIdx = Idx; + + LiveQueryResult LRQ = SR.Query(Idx); + VNInfo *VNI = LRQ.valueIn(); + // For Subranges it is possible that only undef values are left in that + // part of the subregister, so there is no real liverange at the use + if (!VNI) + continue; + + // Special case: An early-clobber tied operand reads and writes the + // register one slot early. + if (VNInfo *DefVNI = LRQ.valueDefined()) + Idx = DefVNI->def; + + WorkList.push_back(std::make_pair(Idx, VNI)); + } + + // Create a new live ranges with only minimal live segments per def. + LiveRange NewLR; + createSegmentsForValues(NewLR, make_range(SR.vni_begin(), SR.vni_end())); + extendSegmentsToUses(NewLR, *Indexes, WorkList, SR); + + // Move the trimmed ranges back. + SR.segments.swap(NewLR.segments); + + // Remove dead PHI value numbers + for (VNInfo *VNI : SR.valnos) { + if (VNI->isUnused()) + continue; + const LiveRange::Segment *Segment = SR.getSegmentContaining(VNI->def); + assert(Segment != nullptr && "Missing segment for VNI"); + if (Segment->end != VNI->def.getDeadSlot()) + continue; + if (VNI->isPHIDef()) { + // This is a dead PHI. Remove it. + DEBUG(dbgs() << "Dead PHI at " << VNI->def << " may separate interval\n"); + VNI->markUnused(); + SR.removeSegment(*Segment); + } + } + + DEBUG(dbgs() << "Shrunk: " << SR << '\n'); +} + +void LiveIntervals::extendToIndices(LiveRange &LR, + ArrayRef<SlotIndex> Indices, + ArrayRef<SlotIndex> Undefs) { + assert(LRCalc && "LRCalc not initialized."); + LRCalc->reset(MF, getSlotIndexes(), DomTree, &getVNInfoAllocator()); + for (SlotIndex Idx : Indices) + LRCalc->extend(LR, Idx, /*PhysReg=*/0, Undefs); +} + +void LiveIntervals::pruneValue(LiveRange &LR, SlotIndex Kill, + SmallVectorImpl<SlotIndex> *EndPoints) { + LiveQueryResult LRQ = LR.Query(Kill); + VNInfo *VNI = LRQ.valueOutOrDead(); + if (!VNI) + return; + + MachineBasicBlock *KillMBB = Indexes->getMBBFromIndex(Kill); + SlotIndex MBBEnd = Indexes->getMBBEndIdx(KillMBB); + + // If VNI isn't live out from KillMBB, the value is trivially pruned. + if (LRQ.endPoint() < MBBEnd) { + LR.removeSegment(Kill, LRQ.endPoint()); + if (EndPoints) EndPoints->push_back(LRQ.endPoint()); + return; + } + + // VNI is live out of KillMBB. + LR.removeSegment(Kill, MBBEnd); + if (EndPoints) EndPoints->push_back(MBBEnd); + + // Find all blocks that are reachable from KillMBB without leaving VNI's live + // range. It is possible that KillMBB itself is reachable, so start a DFS + // from each successor. + using VisitedTy = df_iterator_default_set<MachineBasicBlock*,9>; + VisitedTy Visited; + for (MachineBasicBlock *Succ : KillMBB->successors()) { + for (df_ext_iterator<MachineBasicBlock*, VisitedTy> + I = df_ext_begin(Succ, Visited), E = df_ext_end(Succ, Visited); + I != E;) { + MachineBasicBlock *MBB = *I; + + // Check if VNI is live in to MBB. + SlotIndex MBBStart, MBBEnd; + std::tie(MBBStart, MBBEnd) = Indexes->getMBBRange(MBB); + LiveQueryResult LRQ = LR.Query(MBBStart); + if (LRQ.valueIn() != VNI) { + // This block isn't part of the VNI segment. Prune the search. + I.skipChildren(); + continue; + } + + // Prune the search if VNI is killed in MBB. + if (LRQ.endPoint() < MBBEnd) { + LR.removeSegment(MBBStart, LRQ.endPoint()); + if (EndPoints) EndPoints->push_back(LRQ.endPoint()); + I.skipChildren(); + continue; + } + + // VNI is live through MBB. + LR.removeSegment(MBBStart, MBBEnd); + if (EndPoints) EndPoints->push_back(MBBEnd); + ++I; + } + } +} + +//===----------------------------------------------------------------------===// +// Register allocator hooks. +// + +void LiveIntervals::addKillFlags(const VirtRegMap *VRM) { + // Keep track of regunit ranges. + SmallVector<std::pair<const LiveRange*, LiveRange::const_iterator>, 8> RU; + // Keep track of subregister ranges. + SmallVector<std::pair<const LiveInterval::SubRange*, + LiveRange::const_iterator>, 4> SRs; + + for (unsigned i = 0, e = MRI->getNumVirtRegs(); i != e; ++i) { + unsigned Reg = TargetRegisterInfo::index2VirtReg(i); + if (MRI->reg_nodbg_empty(Reg)) + continue; + const LiveInterval &LI = getInterval(Reg); + if (LI.empty()) + continue; + + // Find the regunit intervals for the assigned register. They may overlap + // the virtual register live range, cancelling any kills. + RU.clear(); + for (MCRegUnitIterator Unit(VRM->getPhys(Reg), TRI); Unit.isValid(); + ++Unit) { + const LiveRange &RURange = getRegUnit(*Unit); + if (RURange.empty()) + continue; + RU.push_back(std::make_pair(&RURange, RURange.find(LI.begin()->end))); + } + + if (MRI->subRegLivenessEnabled()) { + SRs.clear(); + for (const LiveInterval::SubRange &SR : LI.subranges()) { + SRs.push_back(std::make_pair(&SR, SR.find(LI.begin()->end))); + } + } + + // Every instruction that kills Reg corresponds to a segment range end + // point. + for (LiveInterval::const_iterator RI = LI.begin(), RE = LI.end(); RI != RE; + ++RI) { + // A block index indicates an MBB edge. + if (RI->end.isBlock()) + continue; + MachineInstr *MI = getInstructionFromIndex(RI->end); + if (!MI) + continue; + + // Check if any of the regunits are live beyond the end of RI. That could + // happen when a physreg is defined as a copy of a virtreg: + // + // %eax = COPY %5 + // FOO %5 <--- MI, cancel kill because %eax is live. + // BAR killed %eax + // + // There should be no kill flag on FOO when %5 is rewritten as %eax. + for (auto &RUP : RU) { + const LiveRange &RURange = *RUP.first; + LiveRange::const_iterator &I = RUP.second; + if (I == RURange.end()) + continue; + I = RURange.advanceTo(I, RI->end); + if (I == RURange.end() || I->start >= RI->end) + continue; + // I is overlapping RI. + goto CancelKill; + } + + if (MRI->subRegLivenessEnabled()) { + // When reading a partial undefined value we must not add a kill flag. + // The regalloc might have used the undef lane for something else. + // Example: + // %1 = ... ; R32: %1 + // %2:high16 = ... ; R64: %2 + // = read killed %2 ; R64: %2 + // = read %1 ; R32: %1 + // The <kill> flag is correct for %2, but the register allocator may + // assign R0L to %1, and R0 to %2 because the low 32bits of R0 + // are actually never written by %2. After assignment the <kill> + // flag at the read instruction is invalid. + LaneBitmask DefinedLanesMask; + if (!SRs.empty()) { + // Compute a mask of lanes that are defined. + DefinedLanesMask = LaneBitmask::getNone(); + for (auto &SRP : SRs) { + const LiveInterval::SubRange &SR = *SRP.first; + LiveRange::const_iterator &I = SRP.second; + if (I == SR.end()) + continue; + I = SR.advanceTo(I, RI->end); + if (I == SR.end() || I->start >= RI->end) + continue; + // I is overlapping RI + DefinedLanesMask |= SR.LaneMask; + } + } else + DefinedLanesMask = LaneBitmask::getAll(); + + bool IsFullWrite = false; + for (const MachineOperand &MO : MI->operands()) { + if (!MO.isReg() || MO.getReg() != Reg) + continue; + if (MO.isUse()) { + // Reading any undefined lanes? + LaneBitmask UseMask = TRI->getSubRegIndexLaneMask(MO.getSubReg()); + if ((UseMask & ~DefinedLanesMask).any()) + goto CancelKill; + } else if (MO.getSubReg() == 0) { + // Writing to the full register? + assert(MO.isDef()); + IsFullWrite = true; + } + } + + // If an instruction writes to a subregister, a new segment starts in + // the LiveInterval. But as this is only overriding part of the register + // adding kill-flags is not correct here after registers have been + // assigned. + if (!IsFullWrite) { + // Next segment has to be adjacent in the subregister write case. + LiveRange::const_iterator N = std::next(RI); + if (N != LI.end() && N->start == RI->end) + goto CancelKill; + } + } + + MI->addRegisterKilled(Reg, nullptr); + continue; +CancelKill: + MI->clearRegisterKills(Reg, nullptr); + } + } +} + +MachineBasicBlock* +LiveIntervals::intervalIsInOneMBB(const LiveInterval &LI) const { + // A local live range must be fully contained inside the block, meaning it is + // defined and killed at instructions, not at block boundaries. It is not + // live in or or out of any block. + // + // It is technically possible to have a PHI-defined live range identical to a + // single block, but we are going to return false in that case. + + SlotIndex Start = LI.beginIndex(); + if (Start.isBlock()) + return nullptr; + + SlotIndex Stop = LI.endIndex(); + if (Stop.isBlock()) + return nullptr; + + // getMBBFromIndex doesn't need to search the MBB table when both indexes + // belong to proper instructions. + MachineBasicBlock *MBB1 = Indexes->getMBBFromIndex(Start); + MachineBasicBlock *MBB2 = Indexes->getMBBFromIndex(Stop); + return MBB1 == MBB2 ? MBB1 : nullptr; +} + +bool +LiveIntervals::hasPHIKill(const LiveInterval &LI, const VNInfo *VNI) const { + for (const VNInfo *PHI : LI.valnos) { + if (PHI->isUnused() || !PHI->isPHIDef()) + continue; + const MachineBasicBlock *PHIMBB = getMBBFromIndex(PHI->def); + // Conservatively return true instead of scanning huge predecessor lists. + if (PHIMBB->pred_size() > 100) + return true; + for (const MachineBasicBlock *Pred : PHIMBB->predecessors()) + if (VNI == LI.getVNInfoBefore(Indexes->getMBBEndIdx(Pred))) + return true; + } + return false; +} + +float LiveIntervals::getSpillWeight(bool isDef, bool isUse, + const MachineBlockFrequencyInfo *MBFI, + const MachineInstr &MI) { + return getSpillWeight(isDef, isUse, MBFI, MI.getParent()); +} + +float LiveIntervals::getSpillWeight(bool isDef, bool isUse, + const MachineBlockFrequencyInfo *MBFI, + const MachineBasicBlock *MBB) { + BlockFrequency Freq = MBFI->getBlockFreq(MBB); + const float Scale = 1.0f / MBFI->getEntryFreq(); + return (isDef + isUse) * (Freq.getFrequency() * Scale); +} + +LiveRange::Segment +LiveIntervals::addSegmentToEndOfBlock(unsigned reg, MachineInstr &startInst) { + LiveInterval& Interval = createEmptyInterval(reg); + VNInfo *VN = Interval.getNextValue( + SlotIndex(getInstructionIndex(startInst).getRegSlot()), + getVNInfoAllocator()); + LiveRange::Segment S(SlotIndex(getInstructionIndex(startInst).getRegSlot()), + getMBBEndIdx(startInst.getParent()), VN); + Interval.addSegment(S); + + return S; +} + +//===----------------------------------------------------------------------===// +// Register mask functions +//===----------------------------------------------------------------------===// + +bool LiveIntervals::checkRegMaskInterference(LiveInterval &LI, + BitVector &UsableRegs) { + if (LI.empty()) + return false; + LiveInterval::iterator LiveI = LI.begin(), LiveE = LI.end(); + + // Use a smaller arrays for local live ranges. + ArrayRef<SlotIndex> Slots; + ArrayRef<const uint32_t*> Bits; + if (MachineBasicBlock *MBB = intervalIsInOneMBB(LI)) { + Slots = getRegMaskSlotsInBlock(MBB->getNumber()); + Bits = getRegMaskBitsInBlock(MBB->getNumber()); + } else { + Slots = getRegMaskSlots(); + Bits = getRegMaskBits(); + } + + // We are going to enumerate all the register mask slots contained in LI. + // Start with a binary search of RegMaskSlots to find a starting point. + ArrayRef<SlotIndex>::iterator SlotI = + std::lower_bound(Slots.begin(), Slots.end(), LiveI->start); + ArrayRef<SlotIndex>::iterator SlotE = Slots.end(); + + // No slots in range, LI begins after the last call. + if (SlotI == SlotE) + return false; + + bool Found = false; + while (true) { + assert(*SlotI >= LiveI->start); + // Loop over all slots overlapping this segment. + while (*SlotI < LiveI->end) { + // *SlotI overlaps LI. Collect mask bits. + if (!Found) { + // This is the first overlap. Initialize UsableRegs to all ones. + UsableRegs.clear(); + UsableRegs.resize(TRI->getNumRegs(), true); + Found = true; + } + // Remove usable registers clobbered by this mask. + UsableRegs.clearBitsNotInMask(Bits[SlotI-Slots.begin()]); + if (++SlotI == SlotE) + return Found; + } + // *SlotI is beyond the current LI segment. + LiveI = LI.advanceTo(LiveI, *SlotI); + if (LiveI == LiveE) + return Found; + // Advance SlotI until it overlaps. + while (*SlotI < LiveI->start) + if (++SlotI == SlotE) + return Found; + } +} + +//===----------------------------------------------------------------------===// +// IntervalUpdate class. +//===----------------------------------------------------------------------===// + +/// Toolkit used by handleMove to trim or extend live intervals. +class LiveIntervals::HMEditor { +private: + LiveIntervals& LIS; + const MachineRegisterInfo& MRI; + const TargetRegisterInfo& TRI; + SlotIndex OldIdx; + SlotIndex NewIdx; + SmallPtrSet<LiveRange*, 8> Updated; + bool UpdateFlags; + +public: + HMEditor(LiveIntervals& LIS, const MachineRegisterInfo& MRI, + const TargetRegisterInfo& TRI, + SlotIndex OldIdx, SlotIndex NewIdx, bool UpdateFlags) + : LIS(LIS), MRI(MRI), TRI(TRI), OldIdx(OldIdx), NewIdx(NewIdx), + UpdateFlags(UpdateFlags) {} + + // FIXME: UpdateFlags is a workaround that creates live intervals for all + // physregs, even those that aren't needed for regalloc, in order to update + // kill flags. This is wasteful. Eventually, LiveVariables will strip all kill + // flags, and postRA passes will use a live register utility instead. + LiveRange *getRegUnitLI(unsigned Unit) { + if (UpdateFlags && !MRI.isReservedRegUnit(Unit)) + return &LIS.getRegUnit(Unit); + return LIS.getCachedRegUnit(Unit); + } + + /// Update all live ranges touched by MI, assuming a move from OldIdx to + /// NewIdx. + void updateAllRanges(MachineInstr *MI) { + DEBUG(dbgs() << "handleMove " << OldIdx << " -> " << NewIdx << ": " << *MI); + bool hasRegMask = false; + for (MachineOperand &MO : MI->operands()) { + if (MO.isRegMask()) + hasRegMask = true; + if (!MO.isReg()) + continue; + if (MO.isUse()) { + if (!MO.readsReg()) + continue; + // Aggressively clear all kill flags. + // They are reinserted by VirtRegRewriter. + MO.setIsKill(false); + } + + unsigned Reg = MO.getReg(); + if (!Reg) + continue; + if (TargetRegisterInfo::isVirtualRegister(Reg)) { + LiveInterval &LI = LIS.getInterval(Reg); + if (LI.hasSubRanges()) { + unsigned SubReg = MO.getSubReg(); + LaneBitmask LaneMask = SubReg ? TRI.getSubRegIndexLaneMask(SubReg) + : MRI.getMaxLaneMaskForVReg(Reg); + for (LiveInterval::SubRange &S : LI.subranges()) { + if ((S.LaneMask & LaneMask).none()) + continue; + updateRange(S, Reg, S.LaneMask); + } + } + updateRange(LI, Reg, LaneBitmask::getNone()); + continue; + } + + // For physregs, only update the regunits that actually have a + // precomputed live range. + for (MCRegUnitIterator Units(Reg, &TRI); Units.isValid(); ++Units) + if (LiveRange *LR = getRegUnitLI(*Units)) + updateRange(*LR, *Units, LaneBitmask::getNone()); + } + if (hasRegMask) + updateRegMaskSlots(); + } + +private: + /// Update a single live range, assuming an instruction has been moved from + /// OldIdx to NewIdx. + void updateRange(LiveRange &LR, unsigned Reg, LaneBitmask LaneMask) { + if (!Updated.insert(&LR).second) + return; + DEBUG({ + dbgs() << " "; + if (TargetRegisterInfo::isVirtualRegister(Reg)) { + dbgs() << printReg(Reg); + if (LaneMask.any()) + dbgs() << " L" << PrintLaneMask(LaneMask); + } else { + dbgs() << printRegUnit(Reg, &TRI); + } + dbgs() << ":\t" << LR << '\n'; + }); + if (SlotIndex::isEarlierInstr(OldIdx, NewIdx)) + handleMoveDown(LR); + else + handleMoveUp(LR, Reg, LaneMask); + DEBUG(dbgs() << " -->\t" << LR << '\n'); + LR.verify(); + } + + /// Update LR to reflect an instruction has been moved downwards from OldIdx + /// to NewIdx (OldIdx < NewIdx). + void handleMoveDown(LiveRange &LR) { + LiveRange::iterator E = LR.end(); + // Segment going into OldIdx. + LiveRange::iterator OldIdxIn = LR.find(OldIdx.getBaseIndex()); + + // No value live before or after OldIdx? Nothing to do. + if (OldIdxIn == E || SlotIndex::isEarlierInstr(OldIdx, OldIdxIn->start)) + return; + + LiveRange::iterator OldIdxOut; + // Do we have a value live-in to OldIdx? + if (SlotIndex::isEarlierInstr(OldIdxIn->start, OldIdx)) { + // If the live-in value already extends to NewIdx, there is nothing to do. + if (SlotIndex::isEarlierEqualInstr(NewIdx, OldIdxIn->end)) + return; + // Aggressively remove all kill flags from the old kill point. + // Kill flags shouldn't be used while live intervals exist, they will be + // reinserted by VirtRegRewriter. + if (MachineInstr *KillMI = LIS.getInstructionFromIndex(OldIdxIn->end)) + for (MIBundleOperands MO(*KillMI); MO.isValid(); ++MO) + if (MO->isReg() && MO->isUse()) + MO->setIsKill(false); + + // Is there a def before NewIdx which is not OldIdx? + LiveRange::iterator Next = std::next(OldIdxIn); + if (Next != E && !SlotIndex::isSameInstr(OldIdx, Next->start) && + SlotIndex::isEarlierInstr(Next->start, NewIdx)) { + // If we are here then OldIdx was just a use but not a def. We only have + // to ensure liveness extends to NewIdx. + LiveRange::iterator NewIdxIn = + LR.advanceTo(Next, NewIdx.getBaseIndex()); + // Extend the segment before NewIdx if necessary. + if (NewIdxIn == E || + !SlotIndex::isEarlierInstr(NewIdxIn->start, NewIdx)) { + LiveRange::iterator Prev = std::prev(NewIdxIn); + Prev->end = NewIdx.getRegSlot(); + } + // Extend OldIdxIn. + OldIdxIn->end = Next->start; + return; + } + + // Adjust OldIdxIn->end to reach NewIdx. This may temporarily make LR + // invalid by overlapping ranges. + bool isKill = SlotIndex::isSameInstr(OldIdx, OldIdxIn->end); + OldIdxIn->end = NewIdx.getRegSlot(OldIdxIn->end.isEarlyClobber()); + // If this was not a kill, then there was no def and we're done. + if (!isKill) + return; + + // Did we have a Def at OldIdx? + OldIdxOut = Next; + if (OldIdxOut == E || !SlotIndex::isSameInstr(OldIdx, OldIdxOut->start)) + return; + } else { + OldIdxOut = OldIdxIn; + } + + // If we are here then there is a Definition at OldIdx. OldIdxOut points + // to the segment starting there. + assert(OldIdxOut != E && SlotIndex::isSameInstr(OldIdx, OldIdxOut->start) && + "No def?"); + VNInfo *OldIdxVNI = OldIdxOut->valno; + assert(OldIdxVNI->def == OldIdxOut->start && "Inconsistent def"); + + // If the defined value extends beyond NewIdx, just move the beginning + // of the segment to NewIdx. + SlotIndex NewIdxDef = NewIdx.getRegSlot(OldIdxOut->start.isEarlyClobber()); + if (SlotIndex::isEarlierInstr(NewIdxDef, OldIdxOut->end)) { + OldIdxVNI->def = NewIdxDef; + OldIdxOut->start = OldIdxVNI->def; + return; + } + + // If we are here then we have a Definition at OldIdx which ends before + // NewIdx. + + // Is there an existing Def at NewIdx? + LiveRange::iterator AfterNewIdx + = LR.advanceTo(OldIdxOut, NewIdx.getRegSlot()); + bool OldIdxDefIsDead = OldIdxOut->end.isDead(); + if (!OldIdxDefIsDead && + SlotIndex::isEarlierInstr(OldIdxOut->end, NewIdxDef)) { + // OldIdx is not a dead def, and NewIdxDef is inside a new interval. + VNInfo *DefVNI; + if (OldIdxOut != LR.begin() && + !SlotIndex::isEarlierInstr(std::prev(OldIdxOut)->end, + OldIdxOut->start)) { + // There is no gap between OldIdxOut and its predecessor anymore, + // merge them. + LiveRange::iterator IPrev = std::prev(OldIdxOut); + DefVNI = OldIdxVNI; + IPrev->end = OldIdxOut->end; + } else { + // The value is live in to OldIdx + LiveRange::iterator INext = std::next(OldIdxOut); + assert(INext != E && "Must have following segment"); + // We merge OldIdxOut and its successor. As we're dealing with subreg + // reordering, there is always a successor to OldIdxOut in the same BB + // We don't need INext->valno anymore and will reuse for the new segment + // we create later. + DefVNI = OldIdxVNI; + INext->start = OldIdxOut->end; + INext->valno->def = INext->start; + } + // If NewIdx is behind the last segment, extend that and append a new one. + if (AfterNewIdx == E) { + // OldIdxOut is undef at this point, Slide (OldIdxOut;AfterNewIdx] up + // one position. + // |- ?/OldIdxOut -| |- X0 -| ... |- Xn -| end + // => |- X0/OldIdxOut -| ... |- Xn -| |- undef/NewS -| end + std::copy(std::next(OldIdxOut), E, OldIdxOut); + // The last segment is undefined now, reuse it for a dead def. + LiveRange::iterator NewSegment = std::prev(E); + *NewSegment = LiveRange::Segment(NewIdxDef, NewIdxDef.getDeadSlot(), + DefVNI); + DefVNI->def = NewIdxDef; + + LiveRange::iterator Prev = std::prev(NewSegment); + Prev->end = NewIdxDef; + } else { + // OldIdxOut is undef at this point, Slide (OldIdxOut;AfterNewIdx] up + // one position. + // |- ?/OldIdxOut -| |- X0 -| ... |- Xn/AfterNewIdx -| |- Next -| + // => |- X0/OldIdxOut -| ... |- Xn -| |- Xn/AfterNewIdx -| |- Next -| + std::copy(std::next(OldIdxOut), std::next(AfterNewIdx), OldIdxOut); + LiveRange::iterator Prev = std::prev(AfterNewIdx); + // We have two cases: + if (SlotIndex::isEarlierInstr(Prev->start, NewIdxDef)) { + // Case 1: NewIdx is inside a liverange. Split this liverange at + // NewIdxDef into the segment "Prev" followed by "NewSegment". + LiveRange::iterator NewSegment = AfterNewIdx; + *NewSegment = LiveRange::Segment(NewIdxDef, Prev->end, Prev->valno); + Prev->valno->def = NewIdxDef; + + *Prev = LiveRange::Segment(Prev->start, NewIdxDef, DefVNI); + DefVNI->def = Prev->start; + } else { + // Case 2: NewIdx is in a lifetime hole. Keep AfterNewIdx as is and + // turn Prev into a segment from NewIdx to AfterNewIdx->start. + *Prev = LiveRange::Segment(NewIdxDef, AfterNewIdx->start, DefVNI); + DefVNI->def = NewIdxDef; + assert(DefVNI != AfterNewIdx->valno); + } + } + return; + } + + if (AfterNewIdx != E && + SlotIndex::isSameInstr(AfterNewIdx->start, NewIdxDef)) { + // There is an existing def at NewIdx. The def at OldIdx is coalesced into + // that value. + assert(AfterNewIdx->valno != OldIdxVNI && "Multiple defs of value?"); + LR.removeValNo(OldIdxVNI); + } else { + // There was no existing def at NewIdx. We need to create a dead def + // at NewIdx. Shift segments over the old OldIdxOut segment, this frees + // a new segment at the place where we want to construct the dead def. + // |- OldIdxOut -| |- X0 -| ... |- Xn -| |- AfterNewIdx -| + // => |- X0/OldIdxOut -| ... |- Xn -| |- undef/NewS. -| |- AfterNewIdx -| + assert(AfterNewIdx != OldIdxOut && "Inconsistent iterators"); + std::copy(std::next(OldIdxOut), AfterNewIdx, OldIdxOut); + // We can reuse OldIdxVNI now. + LiveRange::iterator NewSegment = std::prev(AfterNewIdx); + VNInfo *NewSegmentVNI = OldIdxVNI; + NewSegmentVNI->def = NewIdxDef; + *NewSegment = LiveRange::Segment(NewIdxDef, NewIdxDef.getDeadSlot(), + NewSegmentVNI); + } + } + + /// Update LR to reflect an instruction has been moved upwards from OldIdx + /// to NewIdx (NewIdx < OldIdx). + void handleMoveUp(LiveRange &LR, unsigned Reg, LaneBitmask LaneMask) { + LiveRange::iterator E = LR.end(); + // Segment going into OldIdx. + LiveRange::iterator OldIdxIn = LR.find(OldIdx.getBaseIndex()); + + // No value live before or after OldIdx? Nothing to do. + if (OldIdxIn == E || SlotIndex::isEarlierInstr(OldIdx, OldIdxIn->start)) + return; + + LiveRange::iterator OldIdxOut; + // Do we have a value live-in to OldIdx? + if (SlotIndex::isEarlierInstr(OldIdxIn->start, OldIdx)) { + // If the live-in value isn't killed here, then we have no Def at + // OldIdx, moreover the value must be live at NewIdx so there is nothing + // to do. + bool isKill = SlotIndex::isSameInstr(OldIdx, OldIdxIn->end); + if (!isKill) + return; + + // At this point we have to move OldIdxIn->end back to the nearest + // previous use or (dead-)def but no further than NewIdx. + SlotIndex DefBeforeOldIdx + = std::max(OldIdxIn->start.getDeadSlot(), + NewIdx.getRegSlot(OldIdxIn->end.isEarlyClobber())); + OldIdxIn->end = findLastUseBefore(DefBeforeOldIdx, Reg, LaneMask); + + // Did we have a Def at OldIdx? If not we are done now. + OldIdxOut = std::next(OldIdxIn); + if (OldIdxOut == E || !SlotIndex::isSameInstr(OldIdx, OldIdxOut->start)) + return; + } else { + OldIdxOut = OldIdxIn; + OldIdxIn = OldIdxOut != LR.begin() ? std::prev(OldIdxOut) : E; + } + + // If we are here then there is a Definition at OldIdx. OldIdxOut points + // to the segment starting there. + assert(OldIdxOut != E && SlotIndex::isSameInstr(OldIdx, OldIdxOut->start) && + "No def?"); + VNInfo *OldIdxVNI = OldIdxOut->valno; + assert(OldIdxVNI->def == OldIdxOut->start && "Inconsistent def"); + bool OldIdxDefIsDead = OldIdxOut->end.isDead(); + + // Is there an existing def at NewIdx? + SlotIndex NewIdxDef = NewIdx.getRegSlot(OldIdxOut->start.isEarlyClobber()); + LiveRange::iterator NewIdxOut = LR.find(NewIdx.getRegSlot()); + if (SlotIndex::isSameInstr(NewIdxOut->start, NewIdx)) { + assert(NewIdxOut->valno != OldIdxVNI && + "Same value defined more than once?"); + // If OldIdx was a dead def remove it. + if (!OldIdxDefIsDead) { + // Remove segment starting at NewIdx and move begin of OldIdxOut to + // NewIdx so it can take its place. + OldIdxVNI->def = NewIdxDef; + OldIdxOut->start = NewIdxDef; + LR.removeValNo(NewIdxOut->valno); + } else { + // Simply remove the dead def at OldIdx. + LR.removeValNo(OldIdxVNI); + } + } else { + // Previously nothing was live after NewIdx, so all we have to do now is + // move the begin of OldIdxOut to NewIdx. + if (!OldIdxDefIsDead) { + // Do we have any intermediate Defs between OldIdx and NewIdx? + if (OldIdxIn != E && + SlotIndex::isEarlierInstr(NewIdxDef, OldIdxIn->start)) { + // OldIdx is not a dead def and NewIdx is before predecessor start. + LiveRange::iterator NewIdxIn = NewIdxOut; + assert(NewIdxIn == LR.find(NewIdx.getBaseIndex())); + const SlotIndex SplitPos = NewIdxDef; + OldIdxVNI = OldIdxIn->valno; + + // Merge the OldIdxIn and OldIdxOut segments into OldIdxOut. + OldIdxOut->valno->def = OldIdxIn->start; + *OldIdxOut = LiveRange::Segment(OldIdxIn->start, OldIdxOut->end, + OldIdxOut->valno); + // OldIdxIn and OldIdxVNI are now undef and can be overridden. + // We Slide [NewIdxIn, OldIdxIn) down one position. + // |- X0/NewIdxIn -| ... |- Xn-1 -||- Xn/OldIdxIn -||- OldIdxOut -| + // => |- undef/NexIdxIn -| |- X0 -| ... |- Xn-1 -| |- Xn/OldIdxOut -| + std::copy_backward(NewIdxIn, OldIdxIn, OldIdxOut); + // NewIdxIn is now considered undef so we can reuse it for the moved + // value. + LiveRange::iterator NewSegment = NewIdxIn; + LiveRange::iterator Next = std::next(NewSegment); + if (SlotIndex::isEarlierInstr(Next->start, NewIdx)) { + // There is no gap between NewSegment and its predecessor. + *NewSegment = LiveRange::Segment(Next->start, SplitPos, + Next->valno); + *Next = LiveRange::Segment(SplitPos, Next->end, OldIdxVNI); + Next->valno->def = SplitPos; + } else { + // There is a gap between NewSegment and its predecessor + // Value becomes live in. + *NewSegment = LiveRange::Segment(SplitPos, Next->start, OldIdxVNI); + NewSegment->valno->def = SplitPos; + } + } else { + // Leave the end point of a live def. + OldIdxOut->start = NewIdxDef; + OldIdxVNI->def = NewIdxDef; + if (OldIdxIn != E && SlotIndex::isEarlierInstr(NewIdx, OldIdxIn->end)) + OldIdxIn->end = NewIdx.getRegSlot(); + } + } else { + // OldIdxVNI is a dead def. It may have been moved across other values + // in LR, so move OldIdxOut up to NewIdxOut. Slide [NewIdxOut;OldIdxOut) + // down one position. + // |- X0/NewIdxOut -| ... |- Xn-1 -| |- Xn/OldIdxOut -| |- next - | + // => |- undef/NewIdxOut -| |- X0 -| ... |- Xn-1 -| |- next -| + std::copy_backward(NewIdxOut, OldIdxOut, std::next(OldIdxOut)); + // OldIdxVNI can be reused now to build a new dead def segment. + LiveRange::iterator NewSegment = NewIdxOut; + VNInfo *NewSegmentVNI = OldIdxVNI; + *NewSegment = LiveRange::Segment(NewIdxDef, NewIdxDef.getDeadSlot(), + NewSegmentVNI); + NewSegmentVNI->def = NewIdxDef; + } + } + } + + void updateRegMaskSlots() { + SmallVectorImpl<SlotIndex>::iterator RI = + std::lower_bound(LIS.RegMaskSlots.begin(), LIS.RegMaskSlots.end(), + OldIdx); + assert(RI != LIS.RegMaskSlots.end() && *RI == OldIdx.getRegSlot() && + "No RegMask at OldIdx."); + *RI = NewIdx.getRegSlot(); + assert((RI == LIS.RegMaskSlots.begin() || + SlotIndex::isEarlierInstr(*std::prev(RI), *RI)) && + "Cannot move regmask instruction above another call"); + assert((std::next(RI) == LIS.RegMaskSlots.end() || + SlotIndex::isEarlierInstr(*RI, *std::next(RI))) && + "Cannot move regmask instruction below another call"); + } + + // Return the last use of reg between NewIdx and OldIdx. + SlotIndex findLastUseBefore(SlotIndex Before, unsigned Reg, + LaneBitmask LaneMask) { + if (TargetRegisterInfo::isVirtualRegister(Reg)) { + SlotIndex LastUse = Before; + for (MachineOperand &MO : MRI.use_nodbg_operands(Reg)) { + if (MO.isUndef()) + continue; + unsigned SubReg = MO.getSubReg(); + if (SubReg != 0 && LaneMask.any() + && (TRI.getSubRegIndexLaneMask(SubReg) & LaneMask).none()) + continue; + + const MachineInstr &MI = *MO.getParent(); + SlotIndex InstSlot = LIS.getSlotIndexes()->getInstructionIndex(MI); + if (InstSlot > LastUse && InstSlot < OldIdx) + LastUse = InstSlot.getRegSlot(); + } + return LastUse; + } + + // This is a regunit interval, so scanning the use list could be very + // expensive. Scan upwards from OldIdx instead. + assert(Before < OldIdx && "Expected upwards move"); + SlotIndexes *Indexes = LIS.getSlotIndexes(); + MachineBasicBlock *MBB = Indexes->getMBBFromIndex(Before); + + // OldIdx may not correspond to an instruction any longer, so set MII to + // point to the next instruction after OldIdx, or MBB->end(). + MachineBasicBlock::iterator MII = MBB->end(); + if (MachineInstr *MI = Indexes->getInstructionFromIndex( + Indexes->getNextNonNullIndex(OldIdx))) + if (MI->getParent() == MBB) + MII = MI; + + MachineBasicBlock::iterator Begin = MBB->begin(); + while (MII != Begin) { + if ((--MII)->isDebugValue()) + continue; + SlotIndex Idx = Indexes->getInstructionIndex(*MII); + + // Stop searching when Before is reached. + if (!SlotIndex::isEarlierInstr(Before, Idx)) + return Before; + + // Check if MII uses Reg. + for (MIBundleOperands MO(*MII); MO.isValid(); ++MO) + if (MO->isReg() && !MO->isUndef() && + TargetRegisterInfo::isPhysicalRegister(MO->getReg()) && + TRI.hasRegUnit(MO->getReg(), Reg)) + return Idx.getRegSlot(); + } + // Didn't reach Before. It must be the first instruction in the block. + return Before; + } +}; + +void LiveIntervals::handleMove(MachineInstr &MI, bool UpdateFlags) { + assert(!MI.isBundled() && "Can't handle bundled instructions yet."); + SlotIndex OldIndex = Indexes->getInstructionIndex(MI); + Indexes->removeMachineInstrFromMaps(MI); + SlotIndex NewIndex = Indexes->insertMachineInstrInMaps(MI); + assert(getMBBStartIdx(MI.getParent()) <= OldIndex && + OldIndex < getMBBEndIdx(MI.getParent()) && + "Cannot handle moves across basic block boundaries."); + + HMEditor HME(*this, *MRI, *TRI, OldIndex, NewIndex, UpdateFlags); + HME.updateAllRanges(&MI); +} + +void LiveIntervals::handleMoveIntoBundle(MachineInstr &MI, + MachineInstr &BundleStart, + bool UpdateFlags) { + SlotIndex OldIndex = Indexes->getInstructionIndex(MI); + SlotIndex NewIndex = Indexes->getInstructionIndex(BundleStart); + HMEditor HME(*this, *MRI, *TRI, OldIndex, NewIndex, UpdateFlags); + HME.updateAllRanges(&MI); +} + +void LiveIntervals::repairOldRegInRange(const MachineBasicBlock::iterator Begin, + const MachineBasicBlock::iterator End, + const SlotIndex endIdx, + LiveRange &LR, const unsigned Reg, + LaneBitmask LaneMask) { + LiveInterval::iterator LII = LR.find(endIdx); + SlotIndex lastUseIdx; + if (LII == LR.begin()) { + // This happens when the function is called for a subregister that only + // occurs _after_ the range that is to be repaired. + return; + } + if (LII != LR.end() && LII->start < endIdx) + lastUseIdx = LII->end; + else + --LII; + + for (MachineBasicBlock::iterator I = End; I != Begin;) { + --I; + MachineInstr &MI = *I; + if (MI.isDebugValue()) + continue; + + SlotIndex instrIdx = getInstructionIndex(MI); + bool isStartValid = getInstructionFromIndex(LII->start); + bool isEndValid = getInstructionFromIndex(LII->end); + + // FIXME: This doesn't currently handle early-clobber or multiple removed + // defs inside of the region to repair. + for (MachineInstr::mop_iterator OI = MI.operands_begin(), + OE = MI.operands_end(); + OI != OE; ++OI) { + const MachineOperand &MO = *OI; + if (!MO.isReg() || MO.getReg() != Reg) + continue; + + unsigned SubReg = MO.getSubReg(); + LaneBitmask Mask = TRI->getSubRegIndexLaneMask(SubReg); + if ((Mask & LaneMask).none()) + continue; + + if (MO.isDef()) { + if (!isStartValid) { + if (LII->end.isDead()) { + SlotIndex prevStart; + if (LII != LR.begin()) + prevStart = std::prev(LII)->start; + + // FIXME: This could be more efficient if there was a + // removeSegment method that returned an iterator. + LR.removeSegment(*LII, true); + if (prevStart.isValid()) + LII = LR.find(prevStart); + else + LII = LR.begin(); + } else { + LII->start = instrIdx.getRegSlot(); + LII->valno->def = instrIdx.getRegSlot(); + if (MO.getSubReg() && !MO.isUndef()) + lastUseIdx = instrIdx.getRegSlot(); + else + lastUseIdx = SlotIndex(); + continue; + } + } + + if (!lastUseIdx.isValid()) { + VNInfo *VNI = LR.getNextValue(instrIdx.getRegSlot(), VNInfoAllocator); + LiveRange::Segment S(instrIdx.getRegSlot(), + instrIdx.getDeadSlot(), VNI); + LII = LR.addSegment(S); + } else if (LII->start != instrIdx.getRegSlot()) { + VNInfo *VNI = LR.getNextValue(instrIdx.getRegSlot(), VNInfoAllocator); + LiveRange::Segment S(instrIdx.getRegSlot(), lastUseIdx, VNI); + LII = LR.addSegment(S); + } + + if (MO.getSubReg() && !MO.isUndef()) + lastUseIdx = instrIdx.getRegSlot(); + else + lastUseIdx = SlotIndex(); + } else if (MO.isUse()) { + // FIXME: This should probably be handled outside of this branch, + // either as part of the def case (for defs inside of the region) or + // after the loop over the region. + if (!isEndValid && !LII->end.isBlock()) + LII->end = instrIdx.getRegSlot(); + if (!lastUseIdx.isValid()) + lastUseIdx = instrIdx.getRegSlot(); + } + } + } +} + +void +LiveIntervals::repairIntervalsInRange(MachineBasicBlock *MBB, + MachineBasicBlock::iterator Begin, + MachineBasicBlock::iterator End, + ArrayRef<unsigned> OrigRegs) { + // Find anchor points, which are at the beginning/end of blocks or at + // instructions that already have indexes. + while (Begin != MBB->begin() && !Indexes->hasIndex(*Begin)) + --Begin; + while (End != MBB->end() && !Indexes->hasIndex(*End)) + ++End; + + SlotIndex endIdx; + if (End == MBB->end()) + endIdx = getMBBEndIdx(MBB).getPrevSlot(); + else + endIdx = getInstructionIndex(*End); + + Indexes->repairIndexesInRange(MBB, Begin, End); + + for (MachineBasicBlock::iterator I = End; I != Begin;) { + --I; + MachineInstr &MI = *I; + if (MI.isDebugValue()) + continue; + for (MachineInstr::const_mop_iterator MOI = MI.operands_begin(), + MOE = MI.operands_end(); + MOI != MOE; ++MOI) { + if (MOI->isReg() && + TargetRegisterInfo::isVirtualRegister(MOI->getReg()) && + !hasInterval(MOI->getReg())) { + createAndComputeVirtRegInterval(MOI->getReg()); + } + } + } + + for (unsigned Reg : OrigRegs) { + if (!TargetRegisterInfo::isVirtualRegister(Reg)) + continue; + + LiveInterval &LI = getInterval(Reg); + // FIXME: Should we support undefs that gain defs? + if (!LI.hasAtLeastOneValue()) + continue; + + for (LiveInterval::SubRange &S : LI.subranges()) + repairOldRegInRange(Begin, End, endIdx, S, Reg, S.LaneMask); + + repairOldRegInRange(Begin, End, endIdx, LI, Reg); + } +} + +void LiveIntervals::removePhysRegDefAt(unsigned Reg, SlotIndex Pos) { + for (MCRegUnitIterator Unit(Reg, TRI); Unit.isValid(); ++Unit) { + if (LiveRange *LR = getCachedRegUnit(*Unit)) + if (VNInfo *VNI = LR->getVNInfoAt(Pos)) + LR->removeValNo(VNI); + } +} + +void LiveIntervals::removeVRegDefAt(LiveInterval &LI, SlotIndex Pos) { + // LI may not have the main range computed yet, but its subranges may + // be present. + VNInfo *VNI = LI.getVNInfoAt(Pos); + if (VNI != nullptr) { + assert(VNI->def.getBaseIndex() == Pos.getBaseIndex()); + LI.removeValNo(VNI); + } + + // Also remove the value defined in subranges. + for (LiveInterval::SubRange &S : LI.subranges()) { + if (VNInfo *SVNI = S.getVNInfoAt(Pos)) + if (SVNI->def.getBaseIndex() == Pos.getBaseIndex()) + S.removeValNo(SVNI); + } + LI.removeEmptySubRanges(); +} + +void LiveIntervals::splitSeparateComponents(LiveInterval &LI, + SmallVectorImpl<LiveInterval*> &SplitLIs) { + ConnectedVNInfoEqClasses ConEQ(*this); + unsigned NumComp = ConEQ.Classify(LI); + if (NumComp <= 1) + return; + DEBUG(dbgs() << " Split " << NumComp << " components: " << LI << '\n'); + unsigned Reg = LI.reg; + const TargetRegisterClass *RegClass = MRI->getRegClass(Reg); + for (unsigned I = 1; I < NumComp; ++I) { + unsigned NewVReg = MRI->createVirtualRegister(RegClass); + LiveInterval &NewLI = createEmptyInterval(NewVReg); + SplitLIs.push_back(&NewLI); + } + ConEQ.Distribute(LI, SplitLIs.data(), *MRI); +} + +void LiveIntervals::constructMainRangeFromSubranges(LiveInterval &LI) { + assert(LRCalc && "LRCalc not initialized."); + LRCalc->reset(MF, getSlotIndexes(), DomTree, &getVNInfoAllocator()); + LRCalc->constructMainRangeFromSubranges(LI); +} |
