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Diffstat (limited to 'contrib/llvm/lib/CodeGen/LiveIntervalAnalysis.cpp')
| -rw-r--r-- | contrib/llvm/lib/CodeGen/LiveIntervalAnalysis.cpp | 1544 |
1 files changed, 1544 insertions, 0 deletions
diff --git a/contrib/llvm/lib/CodeGen/LiveIntervalAnalysis.cpp b/contrib/llvm/lib/CodeGen/LiveIntervalAnalysis.cpp new file mode 100644 index 0000000..3ade660 --- /dev/null +++ b/contrib/llvm/lib/CodeGen/LiveIntervalAnalysis.cpp @@ -0,0 +1,1544 @@ +//===-- LiveIntervalAnalysis.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. +// +//===----------------------------------------------------------------------===// +// +// 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 uses the +// LiveVariables pass to conservatively compute live intervals for +// each virtual and physical register. +// +//===----------------------------------------------------------------------===// + +#define DEBUG_TYPE "regalloc" +#include "llvm/CodeGen/LiveIntervalAnalysis.h" +#include "llvm/Value.h" +#include "llvm/Analysis/AliasAnalysis.h" +#include "llvm/CodeGen/LiveVariables.h" +#include "llvm/CodeGen/MachineInstr.h" +#include "llvm/CodeGen/MachineRegisterInfo.h" +#include "llvm/CodeGen/Passes.h" +#include "llvm/Target/TargetRegisterInfo.h" +#include "llvm/Target/TargetInstrInfo.h" +#include "llvm/Target/TargetMachine.h" +#include "llvm/Support/CommandLine.h" +#include "llvm/Support/Debug.h" +#include "llvm/Support/ErrorHandling.h" +#include "llvm/Support/raw_ostream.h" +#include "llvm/ADT/DenseSet.h" +#include "llvm/ADT/Statistic.h" +#include "llvm/ADT/STLExtras.h" +#include <algorithm> +#include <limits> +#include <cmath> +using namespace llvm; + +// Hidden options for help debugging. +static cl::opt<bool> DisableReMat("disable-rematerialization", + cl::init(false), cl::Hidden); + +STATISTIC(numIntervals , "Number of original intervals"); + +char LiveIntervals::ID = 0; +INITIALIZE_PASS_BEGIN(LiveIntervals, "liveintervals", + "Live Interval Analysis", false, false) +INITIALIZE_AG_DEPENDENCY(AliasAnalysis) +INITIALIZE_PASS_DEPENDENCY(LiveVariables) +INITIALIZE_PASS_DEPENDENCY(MachineDominatorTree) +INITIALIZE_PASS_DEPENDENCY(SlotIndexes) +INITIALIZE_PASS_END(LiveIntervals, "liveintervals", + "Live Interval Analysis", false, false) + +void LiveIntervals::getAnalysisUsage(AnalysisUsage &AU) const { + AU.setPreservesCFG(); + AU.addRequired<AliasAnalysis>(); + AU.addPreserved<AliasAnalysis>(); + AU.addRequired<LiveVariables>(); + AU.addPreserved<LiveVariables>(); + AU.addPreservedID(MachineLoopInfoID); + AU.addPreservedID(MachineDominatorsID); + AU.addPreserved<SlotIndexes>(); + AU.addRequiredTransitive<SlotIndexes>(); + MachineFunctionPass::getAnalysisUsage(AU); +} + +void LiveIntervals::releaseMemory() { + // Free the live intervals themselves. + for (DenseMap<unsigned, LiveInterval*>::iterator I = r2iMap_.begin(), + E = r2iMap_.end(); I != E; ++I) + delete I->second; + + r2iMap_.clear(); + RegMaskSlots.clear(); + RegMaskBits.clear(); + RegMaskBlocks.clear(); + + // Release VNInfo memory regions, VNInfo objects don't need to be dtor'd. + VNInfoAllocator.Reset(); +} + +/// runOnMachineFunction - Register allocate the whole function +/// +bool LiveIntervals::runOnMachineFunction(MachineFunction &fn) { + mf_ = &fn; + mri_ = &mf_->getRegInfo(); + tm_ = &fn.getTarget(); + tri_ = tm_->getRegisterInfo(); + tii_ = tm_->getInstrInfo(); + aa_ = &getAnalysis<AliasAnalysis>(); + lv_ = &getAnalysis<LiveVariables>(); + indexes_ = &getAnalysis<SlotIndexes>(); + allocatableRegs_ = tri_->getAllocatableSet(fn); + reservedRegs_ = tri_->getReservedRegs(fn); + + computeIntervals(); + + numIntervals += getNumIntervals(); + + DEBUG(dump()); + return true; +} + +/// print - Implement the dump method. +void LiveIntervals::print(raw_ostream &OS, const Module* ) const { + OS << "********** INTERVALS **********\n"; + + // Dump the physregs. + for (unsigned Reg = 1, RegE = tri_->getNumRegs(); Reg != RegE; ++Reg) + if (const LiveInterval *LI = r2iMap_.lookup(Reg)) { + LI->print(OS, tri_); + OS << '\n'; + } + + // Dump the virtregs. + for (unsigned Reg = 0, RegE = mri_->getNumVirtRegs(); Reg != RegE; ++Reg) + if (const LiveInterval *LI = + r2iMap_.lookup(TargetRegisterInfo::index2VirtReg(Reg))) { + LI->print(OS, tri_); + OS << '\n'; + } + + printInstrs(OS); +} + +void LiveIntervals::printInstrs(raw_ostream &OS) const { + OS << "********** MACHINEINSTRS **********\n"; + mf_->print(OS, indexes_); +} + +void LiveIntervals::dumpInstrs() const { + printInstrs(dbgs()); +} + +static +bool MultipleDefsBySameMI(const MachineInstr &MI, unsigned MOIdx) { + unsigned Reg = MI.getOperand(MOIdx).getReg(); + for (unsigned i = MOIdx+1, e = MI.getNumOperands(); i < e; ++i) { + const MachineOperand &MO = MI.getOperand(i); + if (!MO.isReg()) + continue; + if (MO.getReg() == Reg && MO.isDef()) { + assert(MI.getOperand(MOIdx).getSubReg() != MO.getSubReg() && + MI.getOperand(MOIdx).getSubReg() && + (MO.getSubReg() || MO.isImplicit())); + return true; + } + } + return false; +} + +/// isPartialRedef - Return true if the specified def at the specific index is +/// partially re-defining the specified live interval. A common case of this is +/// a definition of the sub-register. +bool LiveIntervals::isPartialRedef(SlotIndex MIIdx, MachineOperand &MO, + LiveInterval &interval) { + if (!MO.getSubReg() || MO.isEarlyClobber()) + return false; + + SlotIndex RedefIndex = MIIdx.getRegSlot(); + const LiveRange *OldLR = + interval.getLiveRangeContaining(RedefIndex.getRegSlot(true)); + MachineInstr *DefMI = getInstructionFromIndex(OldLR->valno->def); + if (DefMI != 0) { + return DefMI->findRegisterDefOperandIdx(interval.reg) != -1; + } + return false; +} + +void LiveIntervals::handleVirtualRegisterDef(MachineBasicBlock *mbb, + MachineBasicBlock::iterator mi, + SlotIndex MIIdx, + MachineOperand& MO, + unsigned MOIdx, + LiveInterval &interval) { + DEBUG(dbgs() << "\t\tregister: " << PrintReg(interval.reg, tri_)); + + // Virtual registers may be defined multiple times (due to phi + // elimination and 2-addr elimination). Much of what we do only has to be + // done once for the vreg. We use an empty interval to detect the first + // time we see a vreg. + LiveVariables::VarInfo& vi = lv_->getVarInfo(interval.reg); + if (interval.empty()) { + // Get the Idx of the defining instructions. + SlotIndex defIndex = MIIdx.getRegSlot(MO.isEarlyClobber()); + + // Make sure the first definition is not a partial redefinition. + assert(!MO.readsReg() && "First def cannot also read virtual register " + "missing <undef> flag?"); + + VNInfo *ValNo = interval.getNextValue(defIndex, VNInfoAllocator); + assert(ValNo->id == 0 && "First value in interval is not 0?"); + + // Loop over all of the blocks that the vreg is defined in. There are + // two cases we have to handle here. The most common case is a vreg + // whose lifetime is contained within a basic block. In this case there + // will be a single kill, in MBB, which comes after the definition. + if (vi.Kills.size() == 1 && vi.Kills[0]->getParent() == mbb) { + // FIXME: what about dead vars? + SlotIndex killIdx; + if (vi.Kills[0] != mi) + killIdx = getInstructionIndex(vi.Kills[0]).getRegSlot(); + else + killIdx = defIndex.getDeadSlot(); + + // If the kill happens after the definition, we have an intra-block + // live range. + if (killIdx > defIndex) { + assert(vi.AliveBlocks.empty() && + "Shouldn't be alive across any blocks!"); + LiveRange LR(defIndex, killIdx, ValNo); + interval.addRange(LR); + DEBUG(dbgs() << " +" << LR << "\n"); + return; + } + } + + // The other case we handle is when a virtual register lives to the end + // of the defining block, potentially live across some blocks, then is + // live into some number of blocks, but gets killed. Start by adding a + // range that goes from this definition to the end of the defining block. + LiveRange NewLR(defIndex, getMBBEndIdx(mbb), ValNo); + DEBUG(dbgs() << " +" << NewLR); + interval.addRange(NewLR); + + bool PHIJoin = lv_->isPHIJoin(interval.reg); + + if (PHIJoin) { + // A phi join register is killed at the end of the MBB and revived as a new + // valno in the killing blocks. + assert(vi.AliveBlocks.empty() && "Phi join can't pass through blocks"); + DEBUG(dbgs() << " phi-join"); + ValNo->setHasPHIKill(true); + } else { + // Iterate over all of the blocks that the variable is completely + // live in, adding [insrtIndex(begin), instrIndex(end)+4) to the + // live interval. + for (SparseBitVector<>::iterator I = vi.AliveBlocks.begin(), + E = vi.AliveBlocks.end(); I != E; ++I) { + MachineBasicBlock *aliveBlock = mf_->getBlockNumbered(*I); + LiveRange LR(getMBBStartIdx(aliveBlock), getMBBEndIdx(aliveBlock), ValNo); + interval.addRange(LR); + DEBUG(dbgs() << " +" << LR); + } + } + + // Finally, this virtual register is live from the start of any killing + // block to the 'use' slot of the killing instruction. + for (unsigned i = 0, e = vi.Kills.size(); i != e; ++i) { + MachineInstr *Kill = vi.Kills[i]; + SlotIndex Start = getMBBStartIdx(Kill->getParent()); + SlotIndex killIdx = getInstructionIndex(Kill).getRegSlot(); + + // Create interval with one of a NEW value number. Note that this value + // number isn't actually defined by an instruction, weird huh? :) + if (PHIJoin) { + assert(getInstructionFromIndex(Start) == 0 && + "PHI def index points at actual instruction."); + ValNo = interval.getNextValue(Start, VNInfoAllocator); + ValNo->setIsPHIDef(true); + } + LiveRange LR(Start, killIdx, ValNo); + interval.addRange(LR); + DEBUG(dbgs() << " +" << LR); + } + + } else { + if (MultipleDefsBySameMI(*mi, MOIdx)) + // Multiple defs of the same virtual register by the same instruction. + // e.g. %reg1031:5<def>, %reg1031:6<def> = VLD1q16 %reg1024<kill>, ... + // This is likely due to elimination of REG_SEQUENCE instructions. Return + // here since there is nothing to do. + return; + + // If this is the second time we see a virtual register definition, it + // must be due to phi elimination or two addr elimination. If this is + // the result of two address elimination, then the vreg is one of the + // def-and-use register operand. + + // It may also be partial redef like this: + // 80 %reg1041:6<def> = VSHRNv4i16 %reg1034<kill>, 12, pred:14, pred:%reg0 + // 120 %reg1041:5<def> = VSHRNv4i16 %reg1039<kill>, 12, pred:14, pred:%reg0 + bool PartReDef = isPartialRedef(MIIdx, MO, interval); + if (PartReDef || mi->isRegTiedToUseOperand(MOIdx)) { + // If this is a two-address definition, then we have already processed + // the live range. The only problem is that we didn't realize there + // are actually two values in the live interval. Because of this we + // need to take the LiveRegion that defines this register and split it + // into two values. + SlotIndex RedefIndex = MIIdx.getRegSlot(MO.isEarlyClobber()); + + const LiveRange *OldLR = + interval.getLiveRangeContaining(RedefIndex.getRegSlot(true)); + VNInfo *OldValNo = OldLR->valno; + SlotIndex DefIndex = OldValNo->def.getRegSlot(); + + // Delete the previous value, which should be short and continuous, + // because the 2-addr copy must be in the same MBB as the redef. + interval.removeRange(DefIndex, RedefIndex); + + // The new value number (#1) is defined by the instruction we claimed + // defined value #0. + VNInfo *ValNo = interval.createValueCopy(OldValNo, VNInfoAllocator); + + // Value#0 is now defined by the 2-addr instruction. + OldValNo->def = RedefIndex; + + // Add the new live interval which replaces the range for the input copy. + LiveRange LR(DefIndex, RedefIndex, ValNo); + DEBUG(dbgs() << " replace range with " << LR); + interval.addRange(LR); + + // If this redefinition is dead, we need to add a dummy unit live + // range covering the def slot. + if (MO.isDead()) + interval.addRange(LiveRange(RedefIndex, RedefIndex.getDeadSlot(), + OldValNo)); + + DEBUG({ + dbgs() << " RESULT: "; + interval.print(dbgs(), tri_); + }); + } else if (lv_->isPHIJoin(interval.reg)) { + // In the case of PHI elimination, each variable definition is only + // live until the end of the block. We've already taken care of the + // rest of the live range. + + SlotIndex defIndex = MIIdx.getRegSlot(); + if (MO.isEarlyClobber()) + defIndex = MIIdx.getRegSlot(true); + + VNInfo *ValNo = interval.getNextValue(defIndex, VNInfoAllocator); + + SlotIndex killIndex = getMBBEndIdx(mbb); + LiveRange LR(defIndex, killIndex, ValNo); + interval.addRange(LR); + ValNo->setHasPHIKill(true); + DEBUG(dbgs() << " phi-join +" << LR); + } else { + llvm_unreachable("Multiply defined register"); + } + } + + DEBUG(dbgs() << '\n'); +} + +static bool isRegLiveIntoSuccessor(const MachineBasicBlock *MBB, unsigned Reg) { + for (MachineBasicBlock::const_succ_iterator SI = MBB->succ_begin(), + SE = MBB->succ_end(); + SI != SE; ++SI) { + const MachineBasicBlock* succ = *SI; + if (succ->isLiveIn(Reg)) + return true; + } + return false; +} + +void LiveIntervals::handlePhysicalRegisterDef(MachineBasicBlock *MBB, + MachineBasicBlock::iterator mi, + SlotIndex MIIdx, + MachineOperand& MO, + LiveInterval &interval) { + DEBUG(dbgs() << "\t\tregister: " << PrintReg(interval.reg, tri_)); + + SlotIndex baseIndex = MIIdx; + SlotIndex start = baseIndex.getRegSlot(MO.isEarlyClobber()); + SlotIndex end = start; + + // If it is not used after definition, it is considered dead at + // the instruction defining it. Hence its interval is: + // [defSlot(def), defSlot(def)+1) + // For earlyclobbers, the defSlot was pushed back one; the extra + // advance below compensates. + if (MO.isDead()) { + DEBUG(dbgs() << " dead"); + end = start.getDeadSlot(); + goto exit; + } + + // If it is not dead on definition, it must be killed by a + // subsequent instruction. Hence its interval is: + // [defSlot(def), useSlot(kill)+1) + baseIndex = baseIndex.getNextIndex(); + while (++mi != MBB->end()) { + + if (mi->isDebugValue()) + continue; + if (getInstructionFromIndex(baseIndex) == 0) + baseIndex = indexes_->getNextNonNullIndex(baseIndex); + + if (mi->killsRegister(interval.reg, tri_)) { + DEBUG(dbgs() << " killed"); + end = baseIndex.getRegSlot(); + goto exit; + } else { + int DefIdx = mi->findRegisterDefOperandIdx(interval.reg,false,false,tri_); + if (DefIdx != -1) { + if (mi->isRegTiedToUseOperand(DefIdx)) { + // Two-address instruction. + end = baseIndex.getRegSlot(mi->getOperand(DefIdx).isEarlyClobber()); + } else { + // Another instruction redefines the register before it is ever read. + // Then the register is essentially dead at the instruction that + // defines it. Hence its interval is: + // [defSlot(def), defSlot(def)+1) + DEBUG(dbgs() << " dead"); + end = start.getDeadSlot(); + } + goto exit; + } + } + + baseIndex = baseIndex.getNextIndex(); + } + + // If we get here the register *should* be live out. + assert(!isAllocatable(interval.reg) && "Physregs shouldn't be live out!"); + + // FIXME: We need saner rules for reserved regs. + if (isReserved(interval.reg)) { + end = start.getDeadSlot(); + } else { + // Unreserved, unallocable registers like EFLAGS can be live across basic + // block boundaries. + assert(isRegLiveIntoSuccessor(MBB, interval.reg) && + "Unreserved reg not live-out?"); + end = getMBBEndIdx(MBB); + } +exit: + assert(start < end && "did not find end of interval?"); + + // Already exists? Extend old live interval. + VNInfo *ValNo = interval.getVNInfoAt(start); + bool Extend = ValNo != 0; + if (!Extend) + ValNo = interval.getNextValue(start, VNInfoAllocator); + LiveRange LR(start, end, ValNo); + interval.addRange(LR); + DEBUG(dbgs() << " +" << LR << '\n'); +} + +void LiveIntervals::handleRegisterDef(MachineBasicBlock *MBB, + MachineBasicBlock::iterator MI, + SlotIndex MIIdx, + MachineOperand& MO, + unsigned MOIdx) { + if (TargetRegisterInfo::isVirtualRegister(MO.getReg())) + handleVirtualRegisterDef(MBB, MI, MIIdx, MO, MOIdx, + getOrCreateInterval(MO.getReg())); + else + handlePhysicalRegisterDef(MBB, MI, MIIdx, MO, + getOrCreateInterval(MO.getReg())); +} + +void LiveIntervals::handleLiveInRegister(MachineBasicBlock *MBB, + SlotIndex MIIdx, + LiveInterval &interval) { + assert(TargetRegisterInfo::isPhysicalRegister(interval.reg) && + "Only physical registers can be live in."); + assert((!isAllocatable(interval.reg) || MBB->getParent()->begin() || + MBB->isLandingPad()) && + "Allocatable live-ins only valid for entry blocks and landing pads."); + + DEBUG(dbgs() << "\t\tlivein register: " << PrintReg(interval.reg, tri_)); + + // Look for kills, if it reaches a def before it's killed, then it shouldn't + // be considered a livein. + MachineBasicBlock::iterator mi = MBB->begin(); + MachineBasicBlock::iterator E = MBB->end(); + // Skip over DBG_VALUE at the start of the MBB. + if (mi != E && mi->isDebugValue()) { + while (++mi != E && mi->isDebugValue()) + ; + if (mi == E) + // MBB is empty except for DBG_VALUE's. + return; + } + + SlotIndex baseIndex = MIIdx; + SlotIndex start = baseIndex; + if (getInstructionFromIndex(baseIndex) == 0) + baseIndex = indexes_->getNextNonNullIndex(baseIndex); + + SlotIndex end = baseIndex; + bool SeenDefUse = false; + + while (mi != E) { + if (mi->killsRegister(interval.reg, tri_)) { + DEBUG(dbgs() << " killed"); + end = baseIndex.getRegSlot(); + SeenDefUse = true; + break; + } else if (mi->modifiesRegister(interval.reg, tri_)) { + // Another instruction redefines the register before it is ever read. + // Then the register is essentially dead at the instruction that defines + // it. Hence its interval is: + // [defSlot(def), defSlot(def)+1) + DEBUG(dbgs() << " dead"); + end = start.getDeadSlot(); + SeenDefUse = true; + break; + } + + while (++mi != E && mi->isDebugValue()) + // Skip over DBG_VALUE. + ; + if (mi != E) + baseIndex = indexes_->getNextNonNullIndex(baseIndex); + } + + // Live-in register might not be used at all. + if (!SeenDefUse) { + if (isAllocatable(interval.reg) || + !isRegLiveIntoSuccessor(MBB, interval.reg)) { + // Allocatable registers are never live through. + // Non-allocatable registers that aren't live into any successors also + // aren't live through. + DEBUG(dbgs() << " dead"); + return; + } else { + // If we get here the register is non-allocatable and live into some + // successor. We'll conservatively assume it's live-through. + DEBUG(dbgs() << " live through"); + end = getMBBEndIdx(MBB); + } + } + + SlotIndex defIdx = getMBBStartIdx(MBB); + assert(getInstructionFromIndex(defIdx) == 0 && + "PHI def index points at actual instruction."); + VNInfo *vni = interval.getNextValue(defIdx, VNInfoAllocator); + vni->setIsPHIDef(true); + LiveRange LR(start, end, vni); + + interval.addRange(LR); + DEBUG(dbgs() << " +" << LR << '\n'); +} + +/// computeIntervals - computes the live intervals for virtual +/// registers. for some ordering of the machine instructions [1,N] a +/// live interval is an interval [i, j) where 1 <= i <= j < N for +/// which a variable is live +void LiveIntervals::computeIntervals() { + DEBUG(dbgs() << "********** COMPUTING LIVE INTERVALS **********\n" + << "********** Function: " + << ((Value*)mf_->getFunction())->getName() << '\n'); + + RegMaskBlocks.resize(mf_->getNumBlockIDs()); + + SmallVector<unsigned, 8> UndefUses; + for (MachineFunction::iterator MBBI = mf_->begin(), E = mf_->end(); + MBBI != E; ++MBBI) { + MachineBasicBlock *MBB = MBBI; + RegMaskBlocks[MBB->getNumber()].first = RegMaskSlots.size(); + + if (MBB->empty()) + continue; + + // Track the index of the current machine instr. + SlotIndex MIIndex = getMBBStartIdx(MBB); + DEBUG(dbgs() << "BB#" << MBB->getNumber() + << ":\t\t# derived from " << MBB->getName() << "\n"); + + // Create intervals for live-ins to this BB first. + for (MachineBasicBlock::livein_iterator LI = MBB->livein_begin(), + LE = MBB->livein_end(); LI != LE; ++LI) { + handleLiveInRegister(MBB, MIIndex, getOrCreateInterval(*LI)); + } + + // Skip over empty initial indices. + if (getInstructionFromIndex(MIIndex) == 0) + MIIndex = indexes_->getNextNonNullIndex(MIIndex); + + for (MachineBasicBlock::iterator MI = MBB->begin(), miEnd = MBB->end(); + MI != miEnd; ++MI) { + DEBUG(dbgs() << MIIndex << "\t" << *MI); + if (MI->isDebugValue()) + continue; + assert(indexes_->getInstructionFromIndex(MIIndex) == MI && + "Lost SlotIndex synchronization"); + + // Handle defs. + for (int i = MI->getNumOperands() - 1; i >= 0; --i) { + MachineOperand &MO = MI->getOperand(i); + + // Collect register masks. + if (MO.isRegMask()) { + RegMaskSlots.push_back(MIIndex.getRegSlot()); + RegMaskBits.push_back(MO.getRegMask()); + continue; + } + + if (!MO.isReg() || !MO.getReg()) + continue; + + // handle register defs - build intervals + if (MO.isDef()) + handleRegisterDef(MBB, MI, MIIndex, MO, i); + else if (MO.isUndef()) + UndefUses.push_back(MO.getReg()); + } + + // Move to the next instr slot. + MIIndex = indexes_->getNextNonNullIndex(MIIndex); + } + + // Compute the number of register mask instructions in this block. + std::pair<unsigned, unsigned> &RMB = RegMaskBlocks[MBB->getNumber()]; + RMB.second = RegMaskSlots.size() - RMB.first;; + } + + // Create empty intervals for registers defined by implicit_def's (except + // for those implicit_def that define values which are liveout of their + // blocks. + for (unsigned i = 0, e = UndefUses.size(); i != e; ++i) { + unsigned UndefReg = UndefUses[i]; + (void)getOrCreateInterval(UndefReg); + } +} + +LiveInterval* LiveIntervals::createInterval(unsigned reg) { + float Weight = TargetRegisterInfo::isPhysicalRegister(reg) ? HUGE_VALF : 0.0F; + return new LiveInterval(reg, Weight); +} + +/// dupInterval - Duplicate a live interval. The caller is responsible for +/// managing the allocated memory. +LiveInterval* LiveIntervals::dupInterval(LiveInterval *li) { + LiveInterval *NewLI = createInterval(li->reg); + NewLI->Copy(*li, mri_, getVNInfoAllocator()); + return NewLI; +} + +/// shrinkToUses - After removing some uses of a register, shrink its live +/// range to just the remaining uses. This method does not compute reaching +/// defs for new uses, and it doesn't remove dead defs. +bool LiveIntervals::shrinkToUses(LiveInterval *li, + SmallVectorImpl<MachineInstr*> *dead) { + DEBUG(dbgs() << "Shrink: " << *li << '\n'); + assert(TargetRegisterInfo::isVirtualRegister(li->reg) + && "Can only shrink virtual registers"); + // Find all the values used, including PHI kills. + SmallVector<std::pair<SlotIndex, VNInfo*>, 16> WorkList; + + // Blocks that have already been added to WorkList as live-out. + SmallPtrSet<MachineBasicBlock*, 16> LiveOut; + + // Visit all instructions reading li->reg. + for (MachineRegisterInfo::reg_iterator I = mri_->reg_begin(li->reg); + MachineInstr *UseMI = I.skipInstruction();) { + if (UseMI->isDebugValue() || !UseMI->readsVirtualRegister(li->reg)) + continue; + SlotIndex Idx = getInstructionIndex(UseMI).getRegSlot(); + // Note: This intentionally picks up the wrong VNI in case of an EC redef. + // See below. + VNInfo *VNI = li->getVNInfoBefore(Idx); + 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. The getVNInfoBefore call above would have + // picked up the value defined by UseMI. Adjust the kill slot and value. + if (SlotIndex::isSameInstr(VNI->def, Idx)) { + Idx = VNI->def; + VNI = li->getVNInfoBefore(Idx); + assert(VNI && "Early-clobber tied value not available"); + } + WorkList.push_back(std::make_pair(Idx, VNI)); + } + + // Create a new live interval with only minimal live segments per def. + LiveInterval NewLI(li->reg, 0); + for (LiveInterval::vni_iterator I = li->vni_begin(), E = li->vni_end(); + I != E; ++I) { + VNInfo *VNI = *I; + if (VNI->isUnused()) + continue; + NewLI.addRange(LiveRange(VNI->def, VNI->def.getDeadSlot(), VNI)); + } + + // Keep track of the PHIs that are in use. + SmallPtrSet<VNInfo*, 8> UsedPHIs; + + // 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 = getMBBFromIndex(Idx.getPrevSlot()); + SlotIndex BlockStart = getMBBStartIdx(MBB); + + // Extend the live range for VNI to be live at Idx. + if (VNInfo *ExtVNI = NewLI.extendInBlock(BlockStart, Idx)) { + (void)ExtVNI; + assert(ExtVNI == VNI && "Unexpected existing value number"); + // Is this a PHIDef we haven't seen before? + if (!VNI->isPHIDef() || VNI->def != BlockStart || !UsedPHIs.insert(VNI)) + continue; + // The PHI is live, make sure the predecessors are live-out. + for (MachineBasicBlock::const_pred_iterator PI = MBB->pred_begin(), + PE = MBB->pred_end(); PI != PE; ++PI) { + if (!LiveOut.insert(*PI)) + continue; + SlotIndex Stop = getMBBEndIdx(*PI); + // A predecessor is not required to have a live-out value for a PHI. + if (VNInfo *PVNI = li->getVNInfoBefore(Stop)) + WorkList.push_back(std::make_pair(Stop, PVNI)); + } + continue; + } + + // VNI is live-in to MBB. + DEBUG(dbgs() << " live-in at " << BlockStart << '\n'); + NewLI.addRange(LiveRange(BlockStart, Idx, VNI)); + + // Make sure VNI is live-out from the predecessors. + for (MachineBasicBlock::const_pred_iterator PI = MBB->pred_begin(), + PE = MBB->pred_end(); PI != PE; ++PI) { + if (!LiveOut.insert(*PI)) + continue; + SlotIndex Stop = getMBBEndIdx(*PI); + assert(li->getVNInfoBefore(Stop) == VNI && + "Wrong value out of predecessor"); + WorkList.push_back(std::make_pair(Stop, VNI)); + } + } + + // Handle dead values. + bool CanSeparate = false; + for (LiveInterval::vni_iterator I = li->vni_begin(), E = li->vni_end(); + I != E; ++I) { + VNInfo *VNI = *I; + if (VNI->isUnused()) + continue; + LiveInterval::iterator LII = NewLI.FindLiveRangeContaining(VNI->def); + assert(LII != NewLI.end() && "Missing live range for PHI"); + if (LII->end != VNI->def.getDeadSlot()) + continue; + if (VNI->isPHIDef()) { + // This is a dead PHI. Remove it. + VNI->setIsUnused(true); + NewLI.removeRange(*LII); + DEBUG(dbgs() << "Dead PHI at " << VNI->def << " may separate interval\n"); + CanSeparate = true; + } else { + // This is a dead def. Make sure the instruction knows. + MachineInstr *MI = getInstructionFromIndex(VNI->def); + assert(MI && "No instruction defining live value"); + MI->addRegisterDead(li->reg, tri_); + if (dead && MI->allDefsAreDead()) { + DEBUG(dbgs() << "All defs dead: " << VNI->def << '\t' << *MI); + dead->push_back(MI); + } + } + } + + // Move the trimmed ranges back. + li->ranges.swap(NewLI.ranges); + DEBUG(dbgs() << "Shrunk: " << *li << '\n'); + return CanSeparate; +} + + +//===----------------------------------------------------------------------===// +// Register allocator hooks. +// + +void LiveIntervals::addKillFlags() { + for (iterator I = begin(), E = end(); I != E; ++I) { + unsigned Reg = I->first; + if (TargetRegisterInfo::isPhysicalRegister(Reg)) + continue; + if (mri_->reg_nodbg_empty(Reg)) + continue; + LiveInterval *LI = I->second; + + // Every instruction that kills Reg corresponds to a live range end point. + for (LiveInterval::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; + MI->addRegisterKilled(Reg, NULL); + } + } +} + +/// getReMatImplicitUse - If the remat definition MI has one (for now, we only +/// allow one) virtual register operand, then its uses are implicitly using +/// the register. Returns the virtual register. +unsigned LiveIntervals::getReMatImplicitUse(const LiveInterval &li, + MachineInstr *MI) const { + unsigned RegOp = 0; + for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) { + MachineOperand &MO = MI->getOperand(i); + if (!MO.isReg() || !MO.isUse()) + continue; + unsigned Reg = MO.getReg(); + if (Reg == 0 || Reg == li.reg) + continue; + + if (TargetRegisterInfo::isPhysicalRegister(Reg) && !isAllocatable(Reg)) + continue; + RegOp = MO.getReg(); + break; // Found vreg operand - leave the loop. + } + return RegOp; +} + +/// isValNoAvailableAt - Return true if the val# of the specified interval +/// which reaches the given instruction also reaches the specified use index. +bool LiveIntervals::isValNoAvailableAt(const LiveInterval &li, MachineInstr *MI, + SlotIndex UseIdx) const { + VNInfo *UValNo = li.getVNInfoAt(UseIdx); + return UValNo && UValNo == li.getVNInfoAt(getInstructionIndex(MI)); +} + +/// isReMaterializable - Returns true if the definition MI of the specified +/// val# of the specified interval is re-materializable. +bool +LiveIntervals::isReMaterializable(const LiveInterval &li, + const VNInfo *ValNo, MachineInstr *MI, + const SmallVectorImpl<LiveInterval*> *SpillIs, + bool &isLoad) { + if (DisableReMat) + return false; + + if (!tii_->isTriviallyReMaterializable(MI, aa_)) + return false; + + // Target-specific code can mark an instruction as being rematerializable + // if it has one virtual reg use, though it had better be something like + // a PIC base register which is likely to be live everywhere. + unsigned ImpUse = getReMatImplicitUse(li, MI); + if (ImpUse) { + const LiveInterval &ImpLi = getInterval(ImpUse); + for (MachineRegisterInfo::use_nodbg_iterator + ri = mri_->use_nodbg_begin(li.reg), re = mri_->use_nodbg_end(); + ri != re; ++ri) { + MachineInstr *UseMI = &*ri; + SlotIndex UseIdx = getInstructionIndex(UseMI); + if (li.getVNInfoAt(UseIdx) != ValNo) + continue; + if (!isValNoAvailableAt(ImpLi, MI, UseIdx)) + return false; + } + + // If a register operand of the re-materialized instruction is going to + // be spilled next, then it's not legal to re-materialize this instruction. + if (SpillIs) + for (unsigned i = 0, e = SpillIs->size(); i != e; ++i) + if (ImpUse == (*SpillIs)[i]->reg) + return false; + } + return true; +} + +/// isReMaterializable - Returns true if every definition of MI of every +/// val# of the specified interval is re-materializable. +bool +LiveIntervals::isReMaterializable(const LiveInterval &li, + const SmallVectorImpl<LiveInterval*> *SpillIs, + bool &isLoad) { + isLoad = false; + for (LiveInterval::const_vni_iterator i = li.vni_begin(), e = li.vni_end(); + i != e; ++i) { + const VNInfo *VNI = *i; + if (VNI->isUnused()) + continue; // Dead val#. + // Is the def for the val# rematerializable? + MachineInstr *ReMatDefMI = getInstructionFromIndex(VNI->def); + if (!ReMatDefMI) + return false; + bool DefIsLoad = false; + if (!ReMatDefMI || + !isReMaterializable(li, VNI, ReMatDefMI, SpillIs, DefIsLoad)) + return false; + isLoad |= DefIsLoad; + } + return true; +} + +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 NULL; + + SlotIndex Stop = LI.endIndex(); + if (Stop.isBlock()) + return NULL; + + // 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 : NULL; +} + +float +LiveIntervals::getSpillWeight(bool isDef, bool isUse, unsigned loopDepth) { + // Limit the loop depth ridiculousness. + if (loopDepth > 200) + loopDepth = 200; + + // The loop depth is used to roughly estimate the number of times the + // instruction is executed. Something like 10^d is simple, but will quickly + // overflow a float. This expression behaves like 10^d for small d, but is + // more tempered for large d. At d=200 we get 6.7e33 which leaves a bit of + // headroom before overflow. + // By the way, powf() might be unavailable here. For consistency, + // We may take pow(double,double). + float lc = std::pow(1 + (100.0 / (loopDepth + 10)), (double)loopDepth); + + return (isDef + isUse) * lc; +} + +LiveRange LiveIntervals::addLiveRangeToEndOfBlock(unsigned reg, + MachineInstr* startInst) { + LiveInterval& Interval = getOrCreateInterval(reg); + VNInfo* VN = Interval.getNextValue( + SlotIndex(getInstructionIndex(startInst).getRegSlot()), + getVNInfoAllocator()); + VN->setHasPHIKill(true); + LiveRange LR( + SlotIndex(getInstructionIndex(startInst).getRegSlot()), + getMBBEndIdx(startInst->getParent()), VN); + Interval.addRange(LR); + + return LR; +} + + +//===----------------------------------------------------------------------===// +// 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; + for (;;) { + 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. +//===----------------------------------------------------------------------===// + +// HMEditor is a toolkit used by handleMove to trim or extend live intervals. +class LiveIntervals::HMEditor { +private: + LiveIntervals& LIS; + const MachineRegisterInfo& MRI; + const TargetRegisterInfo& TRI; + SlotIndex NewIdx; + + typedef std::pair<LiveInterval*, LiveRange*> IntRangePair; + typedef DenseSet<IntRangePair> RangeSet; + + struct RegRanges { + LiveRange* Use; + LiveRange* EC; + LiveRange* Dead; + LiveRange* Def; + RegRanges() : Use(0), EC(0), Dead(0), Def(0) {} + }; + typedef DenseMap<unsigned, RegRanges> BundleRanges; + +public: + HMEditor(LiveIntervals& LIS, const MachineRegisterInfo& MRI, + const TargetRegisterInfo& TRI, SlotIndex NewIdx) + : LIS(LIS), MRI(MRI), TRI(TRI), NewIdx(NewIdx) {} + + // Update intervals for all operands of MI from OldIdx to NewIdx. + // This assumes that MI used to be at OldIdx, and now resides at + // NewIdx. + void moveAllRangesFrom(MachineInstr* MI, SlotIndex OldIdx) { + assert(NewIdx != OldIdx && "No-op move? That's a bit strange."); + + // Collect the operands. + RangeSet Entering, Internal, Exiting; + bool hasRegMaskOp = false; + collectRanges(MI, Entering, Internal, Exiting, hasRegMaskOp, OldIdx); + + // To keep the LiveRanges valid within an interval, move the ranges closest + // to the destination first. This prevents ranges from overlapping, to that + // APIs like removeRange still work. + if (NewIdx < OldIdx) { + moveAllEnteringFrom(OldIdx, Entering); + moveAllInternalFrom(OldIdx, Internal); + moveAllExitingFrom(OldIdx, Exiting); + } + else { + moveAllExitingFrom(OldIdx, Exiting); + moveAllInternalFrom(OldIdx, Internal); + moveAllEnteringFrom(OldIdx, Entering); + } + + if (hasRegMaskOp) + updateRegMaskSlots(OldIdx); + +#ifndef NDEBUG + LIValidator validator; + std::for_each(Entering.begin(), Entering.end(), validator); + std::for_each(Internal.begin(), Internal.end(), validator); + std::for_each(Exiting.begin(), Exiting.end(), validator); + assert(validator.rangesOk() && "moveAllOperandsFrom broke liveness."); +#endif + + } + + // Update intervals for all operands of MI to refer to BundleStart's + // SlotIndex. + void moveAllRangesInto(MachineInstr* MI, MachineInstr* BundleStart) { + if (MI == BundleStart) + return; // Bundling instr with itself - nothing to do. + + SlotIndex OldIdx = LIS.getSlotIndexes()->getInstructionIndex(MI); + assert(LIS.getSlotIndexes()->getInstructionFromIndex(OldIdx) == MI && + "SlotIndex <-> Instruction mapping broken for MI"); + + // Collect all ranges already in the bundle. + MachineBasicBlock::instr_iterator BII(BundleStart); + RangeSet Entering, Internal, Exiting; + bool hasRegMaskOp = false; + collectRanges(BII, Entering, Internal, Exiting, hasRegMaskOp, NewIdx); + assert(!hasRegMaskOp && "Can't have RegMask operand in bundle."); + for (++BII; &*BII == MI || BII->isInsideBundle(); ++BII) { + if (&*BII == MI) + continue; + collectRanges(BII, Entering, Internal, Exiting, hasRegMaskOp, NewIdx); + assert(!hasRegMaskOp && "Can't have RegMask operand in bundle."); + } + + BundleRanges BR = createBundleRanges(Entering, Internal, Exiting); + + collectRanges(MI, Entering, Internal, Exiting, hasRegMaskOp, OldIdx); + assert(!hasRegMaskOp && "Can't have RegMask operand in bundle."); + + DEBUG(dbgs() << "Entering: " << Entering.size() << "\n"); + DEBUG(dbgs() << "Internal: " << Internal.size() << "\n"); + DEBUG(dbgs() << "Exiting: " << Exiting.size() << "\n"); + + moveAllEnteringFromInto(OldIdx, Entering, BR); + moveAllInternalFromInto(OldIdx, Internal, BR); + moveAllExitingFromInto(OldIdx, Exiting, BR); + + +#ifndef NDEBUG + LIValidator validator; + std::for_each(Entering.begin(), Entering.end(), validator); + std::for_each(Internal.begin(), Internal.end(), validator); + std::for_each(Exiting.begin(), Exiting.end(), validator); + assert(validator.rangesOk() && "moveAllOperandsInto broke liveness."); +#endif + } + +private: + +#ifndef NDEBUG + class LIValidator { + private: + DenseSet<const LiveInterval*> Checked, Bogus; + public: + void operator()(const IntRangePair& P) { + const LiveInterval* LI = P.first; + if (Checked.count(LI)) + return; + Checked.insert(LI); + if (LI->empty()) + return; + SlotIndex LastEnd = LI->begin()->start; + for (LiveInterval::const_iterator LRI = LI->begin(), LRE = LI->end(); + LRI != LRE; ++LRI) { + const LiveRange& LR = *LRI; + if (LastEnd > LR.start || LR.start >= LR.end) + Bogus.insert(LI); + LastEnd = LR.end; + } + } + + bool rangesOk() const { + return Bogus.empty(); + } + }; +#endif + + // Collect IntRangePairs for all operands of MI that may need fixing. + // Treat's MI's index as OldIdx (regardless of what it is in SlotIndexes' + // maps). + void collectRanges(MachineInstr* MI, RangeSet& Entering, RangeSet& Internal, + RangeSet& Exiting, bool& hasRegMaskOp, SlotIndex OldIdx) { + hasRegMaskOp = false; + for (MachineInstr::mop_iterator MOI = MI->operands_begin(), + MOE = MI->operands_end(); + MOI != MOE; ++MOI) { + const MachineOperand& MO = *MOI; + + if (MO.isRegMask()) { + hasRegMaskOp = true; + continue; + } + + if (!MO.isReg() || MO.getReg() == 0) + continue; + + unsigned Reg = MO.getReg(); + + // TODO: Currently we're skipping uses that are reserved or have no + // interval, but we're not updating their kills. This should be + // fixed. + if (!LIS.hasInterval(Reg) || + (TargetRegisterInfo::isPhysicalRegister(Reg) && LIS.isReserved(Reg))) + continue; + + LiveInterval* LI = &LIS.getInterval(Reg); + + if (MO.readsReg()) { + LiveRange* LR = LI->getLiveRangeContaining(OldIdx); + if (LR != 0) + Entering.insert(std::make_pair(LI, LR)); + } + if (MO.isDef()) { + if (MO.isEarlyClobber()) { + LiveRange* LR = LI->getLiveRangeContaining(OldIdx.getRegSlot(true)); + assert(LR != 0 && "No EC range?"); + if (LR->end > OldIdx.getDeadSlot()) + Exiting.insert(std::make_pair(LI, LR)); + else + Internal.insert(std::make_pair(LI, LR)); + } else if (MO.isDead()) { + LiveRange* LR = LI->getLiveRangeContaining(OldIdx.getRegSlot()); + assert(LR != 0 && "No dead-def range?"); + Internal.insert(std::make_pair(LI, LR)); + } else { + LiveRange* LR = LI->getLiveRangeContaining(OldIdx.getDeadSlot()); + assert(LR && LR->end > OldIdx.getDeadSlot() && + "Non-dead-def should have live range exiting."); + Exiting.insert(std::make_pair(LI, LR)); + } + } + } + } + + // Collect IntRangePairs for all operands of MI that may need fixing. + void collectRangesInBundle(MachineInstr* MI, RangeSet& Entering, + RangeSet& Exiting, SlotIndex MIStartIdx, + SlotIndex MIEndIdx) { + for (MachineInstr::mop_iterator MOI = MI->operands_begin(), + MOE = MI->operands_end(); + MOI != MOE; ++MOI) { + const MachineOperand& MO = *MOI; + assert(!MO.isRegMask() && "Can't have RegMasks in bundles."); + if (!MO.isReg() || MO.getReg() == 0) + continue; + + unsigned Reg = MO.getReg(); + + // TODO: Currently we're skipping uses that are reserved or have no + // interval, but we're not updating their kills. This should be + // fixed. + if (!LIS.hasInterval(Reg) || + (TargetRegisterInfo::isPhysicalRegister(Reg) && LIS.isReserved(Reg))) + continue; + + LiveInterval* LI = &LIS.getInterval(Reg); + + if (MO.readsReg()) { + LiveRange* LR = LI->getLiveRangeContaining(MIStartIdx); + if (LR != 0) + Entering.insert(std::make_pair(LI, LR)); + } + if (MO.isDef()) { + assert(!MO.isEarlyClobber() && "Early clobbers not allowed in bundles."); + assert(!MO.isDead() && "Dead-defs not allowed in bundles."); + LiveRange* LR = LI->getLiveRangeContaining(MIEndIdx.getDeadSlot()); + assert(LR != 0 && "Internal ranges not allowed in bundles."); + Exiting.insert(std::make_pair(LI, LR)); + } + } + } + + BundleRanges createBundleRanges(RangeSet& Entering, RangeSet& Internal, RangeSet& Exiting) { + BundleRanges BR; + + for (RangeSet::iterator EI = Entering.begin(), EE = Entering.end(); + EI != EE; ++EI) { + LiveInterval* LI = EI->first; + LiveRange* LR = EI->second; + BR[LI->reg].Use = LR; + } + + for (RangeSet::iterator II = Internal.begin(), IE = Internal.end(); + II != IE; ++II) { + LiveInterval* LI = II->first; + LiveRange* LR = II->second; + if (LR->end.isDead()) { + BR[LI->reg].Dead = LR; + } else { + BR[LI->reg].EC = LR; + } + } + + for (RangeSet::iterator EI = Exiting.begin(), EE = Exiting.end(); + EI != EE; ++EI) { + LiveInterval* LI = EI->first; + LiveRange* LR = EI->second; + BR[LI->reg].Def = LR; + } + + return BR; + } + + void moveKillFlags(unsigned reg, SlotIndex OldIdx, SlotIndex newKillIdx) { + MachineInstr* OldKillMI = LIS.getInstructionFromIndex(OldIdx); + if (!OldKillMI->killsRegister(reg)) + return; // Bail out if we don't have kill flags on the old register. + MachineInstr* NewKillMI = LIS.getInstructionFromIndex(newKillIdx); + assert(OldKillMI->killsRegister(reg) && "Old 'kill' instr isn't a kill."); + assert(!NewKillMI->killsRegister(reg) && "New kill instr is already a kill."); + OldKillMI->clearRegisterKills(reg, &TRI); + NewKillMI->addRegisterKilled(reg, &TRI); + } + + void updateRegMaskSlots(SlotIndex OldIdx) { + SmallVectorImpl<SlotIndex>::iterator RI = + std::lower_bound(LIS.RegMaskSlots.begin(), LIS.RegMaskSlots.end(), + OldIdx); + assert(*RI == OldIdx && "No RegMask at OldIdx."); + *RI = NewIdx; + assert(*prior(RI) < *RI && *RI < *next(RI) && + "RegSlots out of order. Did you move one call across another?"); + } + + // Return the last use of reg between NewIdx and OldIdx. + SlotIndex findLastUseBefore(unsigned Reg, SlotIndex OldIdx) { + SlotIndex LastUse = NewIdx; + for (MachineRegisterInfo::use_nodbg_iterator + UI = MRI.use_nodbg_begin(Reg), + UE = MRI.use_nodbg_end(); + UI != UE; UI.skipInstruction()) { + const MachineInstr* MI = &*UI; + SlotIndex InstSlot = LIS.getSlotIndexes()->getInstructionIndex(MI); + if (InstSlot > LastUse && InstSlot < OldIdx) + LastUse = InstSlot; + } + return LastUse; + } + + void moveEnteringUpFrom(SlotIndex OldIdx, IntRangePair& P) { + LiveInterval* LI = P.first; + LiveRange* LR = P.second; + bool LiveThrough = LR->end > OldIdx.getRegSlot(); + if (LiveThrough) + return; + SlotIndex LastUse = findLastUseBefore(LI->reg, OldIdx); + if (LastUse != NewIdx) + moveKillFlags(LI->reg, NewIdx, LastUse); + LR->end = LastUse.getRegSlot(); + } + + void moveEnteringDownFrom(SlotIndex OldIdx, IntRangePair& P) { + LiveInterval* LI = P.first; + LiveRange* LR = P.second; + // Extend the LiveRange if NewIdx is past the end. + if (NewIdx > LR->end) { + // Move kill flags if OldIdx was not originally the end + // (otherwise LR->end points to an invalid slot). + if (LR->end.getRegSlot() != OldIdx.getRegSlot()) { + assert(LR->end > OldIdx && "LiveRange does not cover original slot"); + moveKillFlags(LI->reg, LR->end, NewIdx); + } + LR->end = NewIdx.getRegSlot(); + } + } + + void moveAllEnteringFrom(SlotIndex OldIdx, RangeSet& Entering) { + bool GoingUp = NewIdx < OldIdx; + + if (GoingUp) { + for (RangeSet::iterator EI = Entering.begin(), EE = Entering.end(); + EI != EE; ++EI) + moveEnteringUpFrom(OldIdx, *EI); + } else { + for (RangeSet::iterator EI = Entering.begin(), EE = Entering.end(); + EI != EE; ++EI) + moveEnteringDownFrom(OldIdx, *EI); + } + } + + void moveInternalFrom(SlotIndex OldIdx, IntRangePair& P) { + LiveInterval* LI = P.first; + LiveRange* LR = P.second; + assert(OldIdx < LR->start && LR->start < OldIdx.getDeadSlot() && + LR->end <= OldIdx.getDeadSlot() && + "Range should be internal to OldIdx."); + LiveRange Tmp(*LR); + Tmp.start = NewIdx.getRegSlot(LR->start.isEarlyClobber()); + Tmp.valno->def = Tmp.start; + Tmp.end = LR->end.isDead() ? NewIdx.getDeadSlot() : NewIdx.getRegSlot(); + LI->removeRange(*LR); + LI->addRange(Tmp); + } + + void moveAllInternalFrom(SlotIndex OldIdx, RangeSet& Internal) { + for (RangeSet::iterator II = Internal.begin(), IE = Internal.end(); + II != IE; ++II) + moveInternalFrom(OldIdx, *II); + } + + void moveExitingFrom(SlotIndex OldIdx, IntRangePair& P) { + LiveRange* LR = P.second; + assert(OldIdx < LR->start && LR->start < OldIdx.getDeadSlot() && + "Range should start in OldIdx."); + assert(LR->end > OldIdx.getDeadSlot() && "Range should exit OldIdx."); + SlotIndex NewStart = NewIdx.getRegSlot(LR->start.isEarlyClobber()); + LR->start = NewStart; + LR->valno->def = NewStart; + } + + void moveAllExitingFrom(SlotIndex OldIdx, RangeSet& Exiting) { + for (RangeSet::iterator EI = Exiting.begin(), EE = Exiting.end(); + EI != EE; ++EI) + moveExitingFrom(OldIdx, *EI); + } + + void moveEnteringUpFromInto(SlotIndex OldIdx, IntRangePair& P, + BundleRanges& BR) { + LiveInterval* LI = P.first; + LiveRange* LR = P.second; + bool LiveThrough = LR->end > OldIdx.getRegSlot(); + if (LiveThrough) { + assert((LR->start < NewIdx || BR[LI->reg].Def == LR) && + "Def in bundle should be def range."); + assert((BR[LI->reg].Use == 0 || BR[LI->reg].Use == LR) && + "If bundle has use for this reg it should be LR."); + BR[LI->reg].Use = LR; + return; + } + + SlotIndex LastUse = findLastUseBefore(LI->reg, OldIdx); + moveKillFlags(LI->reg, OldIdx, LastUse); + + if (LR->start < NewIdx) { + // Becoming a new entering range. + assert(BR[LI->reg].Dead == 0 && BR[LI->reg].Def == 0 && + "Bundle shouldn't be re-defining reg mid-range."); + assert((BR[LI->reg].Use == 0 || BR[LI->reg].Use == LR) && + "Bundle shouldn't have different use range for same reg."); + LR->end = LastUse.getRegSlot(); + BR[LI->reg].Use = LR; + } else { + // Becoming a new Dead-def. + assert(LR->start == NewIdx.getRegSlot(LR->start.isEarlyClobber()) && + "Live range starting at unexpected slot."); + assert(BR[LI->reg].Def == LR && "Reg should have def range."); + assert(BR[LI->reg].Dead == 0 && + "Can't have def and dead def of same reg in a bundle."); + LR->end = LastUse.getDeadSlot(); + BR[LI->reg].Dead = BR[LI->reg].Def; + BR[LI->reg].Def = 0; + } + } + + void moveEnteringDownFromInto(SlotIndex OldIdx, IntRangePair& P, + BundleRanges& BR) { + LiveInterval* LI = P.first; + LiveRange* LR = P.second; + if (NewIdx > LR->end) { + // Range extended to bundle. Add to bundle uses. + // Note: Currently adds kill flags to bundle start. + assert(BR[LI->reg].Use == 0 && + "Bundle already has use range for reg."); + moveKillFlags(LI->reg, LR->end, NewIdx); + LR->end = NewIdx.getRegSlot(); + BR[LI->reg].Use = LR; + } else { + assert(BR[LI->reg].Use != 0 && + "Bundle should already have a use range for reg."); + } + } + + void moveAllEnteringFromInto(SlotIndex OldIdx, RangeSet& Entering, + BundleRanges& BR) { + bool GoingUp = NewIdx < OldIdx; + + if (GoingUp) { + for (RangeSet::iterator EI = Entering.begin(), EE = Entering.end(); + EI != EE; ++EI) + moveEnteringUpFromInto(OldIdx, *EI, BR); + } else { + for (RangeSet::iterator EI = Entering.begin(), EE = Entering.end(); + EI != EE; ++EI) + moveEnteringDownFromInto(OldIdx, *EI, BR); + } + } + + void moveInternalFromInto(SlotIndex OldIdx, IntRangePair& P, + BundleRanges& BR) { + // TODO: Sane rules for moving ranges into bundles. + } + + void moveAllInternalFromInto(SlotIndex OldIdx, RangeSet& Internal, + BundleRanges& BR) { + for (RangeSet::iterator II = Internal.begin(), IE = Internal.end(); + II != IE; ++II) + moveInternalFromInto(OldIdx, *II, BR); + } + + void moveExitingFromInto(SlotIndex OldIdx, IntRangePair& P, + BundleRanges& BR) { + LiveInterval* LI = P.first; + LiveRange* LR = P.second; + + assert(LR->start.isRegister() && + "Don't know how to merge exiting ECs into bundles yet."); + + if (LR->end > NewIdx.getDeadSlot()) { + // This range is becoming an exiting range on the bundle. + // If there was an old dead-def of this reg, delete it. + if (BR[LI->reg].Dead != 0) { + LI->removeRange(*BR[LI->reg].Dead); + BR[LI->reg].Dead = 0; + } + assert(BR[LI->reg].Def == 0 && + "Can't have two defs for the same variable exiting a bundle."); + LR->start = NewIdx.getRegSlot(); + LR->valno->def = LR->start; + BR[LI->reg].Def = LR; + } else { + // This range is becoming internal to the bundle. + assert(LR->end == NewIdx.getRegSlot() && + "Can't bundle def whose kill is before the bundle"); + if (BR[LI->reg].Dead || BR[LI->reg].Def) { + // Already have a def for this. Just delete range. + LI->removeRange(*LR); + } else { + // Make range dead, record. + LR->end = NewIdx.getDeadSlot(); + BR[LI->reg].Dead = LR; + assert(BR[LI->reg].Use == LR && + "Range becoming dead should currently be use."); + } + // In both cases the range is no longer a use on the bundle. + BR[LI->reg].Use = 0; + } + } + + void moveAllExitingFromInto(SlotIndex OldIdx, RangeSet& Exiting, + BundleRanges& BR) { + for (RangeSet::iterator EI = Exiting.begin(), EE = Exiting.end(); + EI != EE; ++EI) + moveExitingFromInto(OldIdx, *EI, BR); + } + +}; + +void LiveIntervals::handleMove(MachineInstr* MI) { + SlotIndex OldIndex = indexes_->getInstructionIndex(MI); + indexes_->removeMachineInstrFromMaps(MI); + SlotIndex NewIndex = MI->isInsideBundle() ? + indexes_->getInstructionIndex(MI) : + indexes_->insertMachineInstrInMaps(MI); + assert(getMBBStartIdx(MI->getParent()) <= OldIndex && + OldIndex < getMBBEndIdx(MI->getParent()) && + "Cannot handle moves across basic block boundaries."); + assert(!MI->isBundled() && "Can't handle bundled instructions yet."); + + HMEditor HME(*this, *mri_, *tri_, NewIndex); + HME.moveAllRangesFrom(MI, OldIndex); +} + +void LiveIntervals::handleMoveIntoBundle(MachineInstr* MI, MachineInstr* BundleStart) { + SlotIndex NewIndex = indexes_->getInstructionIndex(BundleStart); + HMEditor HME(*this, *mri_, *tri_, NewIndex); + HME.moveAllRangesInto(MI, BundleStart); +} |
