X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FTargetInstrInfoImpl.cpp;h=8ed66f704430ef4f790d19e319d1800882d7e326;hb=ebd7eabca4c090175b71f221e880f8bd937a4523;hp=5b1d5a62ffbb07dfe8a5e5b2a2abcd9c617c7773;hpb=744b3a5acdbd4d0fac9c6a7c9ad702502cc3cc37;p=oota-llvm.git diff --git a/lib/CodeGen/TargetInstrInfoImpl.cpp b/lib/CodeGen/TargetInstrInfoImpl.cpp index 5b1d5a62ffb..8ed66f70443 100644 --- a/lib/CodeGen/TargetInstrInfoImpl.cpp +++ b/lib/CodeGen/TargetInstrInfoImpl.cpp @@ -22,12 +22,19 @@ #include "llvm/CodeGen/MachineInstrBuilder.h" #include "llvm/CodeGen/MachineMemOperand.h" #include "llvm/CodeGen/MachineRegisterInfo.h" -#include "llvm/CodeGen/PostRAHazardRecognizer.h" +#include "llvm/CodeGen/ScoreboardHazardRecognizer.h" #include "llvm/CodeGen/PseudoSourceValue.h" +#include "llvm/MC/MCInstrItineraries.h" +#include "llvm/Support/CommandLine.h" +#include "llvm/Support/Debug.h" #include "llvm/Support/ErrorHandling.h" #include "llvm/Support/raw_ostream.h" using namespace llvm; +static cl::opt DisableHazardRecognizer( + "disable-sched-hazard", cl::Hidden, cl::init(false), + cl::desc("Disable hazard detection during preRA scheduling")); + /// ReplaceTailWithBranchTo - Delete the instruction OldInst and everything /// after it, replacing it with an unconditional branch to NewDest. void @@ -53,8 +60,8 @@ TargetInstrInfoImpl::ReplaceTailWithBranchTo(MachineBasicBlock::iterator Tail, // the two operands returned by findCommutedOpIndices. MachineInstr *TargetInstrInfoImpl::commuteInstruction(MachineInstr *MI, bool NewMI) const { - const TargetInstrDesc &TID = MI->getDesc(); - bool HasDef = TID.getNumDefs(); + const MCInstrDesc &MCID = MI->getDesc(); + bool HasDef = MCID.getNumDefs(); if (HasDef && !MI->getOperand(0).isReg()) // No idea how to commute this instruction. Target should implement its own. return 0; @@ -68,40 +75,42 @@ MachineInstr *TargetInstrInfoImpl::commuteInstruction(MachineInstr *MI, assert(MI->getOperand(Idx1).isReg() && MI->getOperand(Idx2).isReg() && "This only knows how to commute register operands so far"); + unsigned Reg0 = HasDef ? MI->getOperand(0).getReg() : 0; unsigned Reg1 = MI->getOperand(Idx1).getReg(); unsigned Reg2 = MI->getOperand(Idx2).getReg(); + unsigned SubReg0 = HasDef ? MI->getOperand(0).getSubReg() : 0; + unsigned SubReg1 = MI->getOperand(Idx1).getSubReg(); + unsigned SubReg2 = MI->getOperand(Idx2).getSubReg(); bool Reg1IsKill = MI->getOperand(Idx1).isKill(); bool Reg2IsKill = MI->getOperand(Idx2).isKill(); - bool ChangeReg0 = false; - if (HasDef && MI->getOperand(0).getReg() == Reg1) { - // Must be two address instruction! - assert(MI->getDesc().getOperandConstraint(0, TOI::TIED_TO) && - "Expecting a two-address instruction!"); + // If destination is tied to either of the commuted source register, then + // it must be updated. + if (HasDef && Reg0 == Reg1 && + MI->getDesc().getOperandConstraint(Idx1, MCOI::TIED_TO) == 0) { Reg2IsKill = false; - ChangeReg0 = true; + Reg0 = Reg2; + SubReg0 = SubReg2; + } else if (HasDef && Reg0 == Reg2 && + MI->getDesc().getOperandConstraint(Idx2, MCOI::TIED_TO) == 0) { + Reg1IsKill = false; + Reg0 = Reg1; + SubReg0 = SubReg1; } if (NewMI) { // Create a new instruction. - unsigned Reg0 = HasDef - ? (ChangeReg0 ? Reg2 : MI->getOperand(0).getReg()) : 0; - bool Reg0IsDead = HasDef ? MI->getOperand(0).isDead() : false; MachineFunction &MF = *MI->getParent()->getParent(); - if (HasDef) - return BuildMI(MF, MI->getDebugLoc(), MI->getDesc()) - .addReg(Reg0, RegState::Define | getDeadRegState(Reg0IsDead)) - .addReg(Reg2, getKillRegState(Reg2IsKill)) - .addReg(Reg1, getKillRegState(Reg2IsKill)); - else - return BuildMI(MF, MI->getDebugLoc(), MI->getDesc()) - .addReg(Reg2, getKillRegState(Reg2IsKill)) - .addReg(Reg1, getKillRegState(Reg2IsKill)); + MI = MF.CloneMachineInstr(MI); } - if (ChangeReg0) - MI->getOperand(0).setReg(Reg2); + if (HasDef) { + MI->getOperand(0).setReg(Reg0); + MI->getOperand(0).setSubReg(SubReg0); + } MI->getOperand(Idx2).setReg(Reg1); MI->getOperand(Idx1).setReg(Reg2); + MI->getOperand(Idx2).setSubReg(SubReg1); + MI->getOperand(Idx1).setSubReg(SubReg2); MI->getOperand(Idx2).setIsKill(Reg1IsKill); MI->getOperand(Idx1).setIsKill(Reg2IsKill); return MI; @@ -113,12 +122,15 @@ MachineInstr *TargetInstrInfoImpl::commuteInstruction(MachineInstr *MI, bool TargetInstrInfoImpl::findCommutedOpIndices(MachineInstr *MI, unsigned &SrcOpIdx1, unsigned &SrcOpIdx2) const { - const TargetInstrDesc &TID = MI->getDesc(); - if (!TID.isCommutable()) + assert(!MI->isBundle() && + "TargetInstrInfoImpl::findCommutedOpIndices() can't handle bundles"); + + const MCInstrDesc &MCID = MI->getDesc(); + if (!MCID.isCommutable()) return false; // This assumes v0 = op v1, v2 and commuting would swap v1 and v2. If this // is not true, then the target must implement this. - SrcOpIdx1 = TID.getNumDefs(); + SrcOpIdx1 = MCID.getNumDefs(); SrcOpIdx2 = SrcOpIdx1 + 1; if (!MI->getOperand(SrcOpIdx1).isReg() || !MI->getOperand(SrcOpIdx2).isReg()) @@ -128,15 +140,32 @@ bool TargetInstrInfoImpl::findCommutedOpIndices(MachineInstr *MI, } +bool +TargetInstrInfoImpl::isUnpredicatedTerminator(const MachineInstr *MI) const { + if (!MI->isTerminator()) return false; + + // Conditional branch is a special case. + if (MI->isBranch() && !MI->isBarrier()) + return true; + if (!MI->isPredicable()) + return true; + return !isPredicated(MI); +} + + bool TargetInstrInfoImpl::PredicateInstruction(MachineInstr *MI, const SmallVectorImpl &Pred) const { bool MadeChange = false; - const TargetInstrDesc &TID = MI->getDesc(); - if (!TID.isPredicable()) + + assert(!MI->isBundle() && + "TargetInstrInfoImpl::PredicateInstruction() can't handle bundles"); + + const MCInstrDesc &MCID = MI->getDesc(); + if (!MI->isPredicable()) return false; - + for (unsigned j = 0, i = 0, e = MI->getNumOperands(); i != e; ++i) { - if (TID.OpInfo[i].isPredicate()) { + if (MCID.OpInfo[i].isPredicate()) { MachineOperand &MO = MI->getOperand(i); if (MO.isReg()) { MO.setReg(Pred[j].getReg()); @@ -154,6 +183,42 @@ bool TargetInstrInfoImpl::PredicateInstruction(MachineInstr *MI, return MadeChange; } +bool TargetInstrInfoImpl::hasLoadFromStackSlot(const MachineInstr *MI, + const MachineMemOperand *&MMO, + int &FrameIndex) const { + for (MachineInstr::mmo_iterator o = MI->memoperands_begin(), + oe = MI->memoperands_end(); + o != oe; + ++o) { + if ((*o)->isLoad() && (*o)->getValue()) + if (const FixedStackPseudoSourceValue *Value = + dyn_cast((*o)->getValue())) { + FrameIndex = Value->getFrameIndex(); + MMO = *o; + return true; + } + } + return false; +} + +bool TargetInstrInfoImpl::hasStoreToStackSlot(const MachineInstr *MI, + const MachineMemOperand *&MMO, + int &FrameIndex) const { + for (MachineInstr::mmo_iterator o = MI->memoperands_begin(), + oe = MI->memoperands_end(); + o != oe; + ++o) { + if ((*o)->isStore() && (*o)->getValue()) + if (const FixedStackPseudoSourceValue *Value = + dyn_cast((*o)->getValue())) { + FrameIndex = Value->getFrameIndex(); + MMO = *o; + return true; + } + } + return false; +} + void TargetInstrInfoImpl::reMaterialize(MachineBasicBlock &MBB, MachineBasicBlock::iterator I, unsigned DestReg, @@ -165,31 +230,20 @@ void TargetInstrInfoImpl::reMaterialize(MachineBasicBlock &MBB, MBB.insert(I, MI); } -bool TargetInstrInfoImpl::produceSameValue(const MachineInstr *MI0, - const MachineInstr *MI1) const { +bool +TargetInstrInfoImpl::produceSameValue(const MachineInstr *MI0, + const MachineInstr *MI1, + const MachineRegisterInfo *MRI) const { return MI0->isIdenticalTo(MI1, MachineInstr::IgnoreVRegDefs); } MachineInstr *TargetInstrInfoImpl::duplicate(MachineInstr *Orig, MachineFunction &MF) const { - assert(!Orig->getDesc().isNotDuplicable() && + assert(!Orig->isNotDuplicable() && "Instruction cannot be duplicated"); return MF.CloneMachineInstr(Orig); } -unsigned -TargetInstrInfoImpl::GetFunctionSizeInBytes(const MachineFunction &MF) const { - unsigned FnSize = 0; - for (MachineFunction::const_iterator MBBI = MF.begin(), E = MF.end(); - MBBI != E; ++MBBI) { - const MachineBasicBlock &MBB = *MBBI; - for (MachineBasicBlock::const_iterator I = MBB.begin(),E = MBB.end(); - I != E; ++I) - FnSize += GetInstSizeInBytes(I); - } - return FnSize; -} - // If the COPY instruction in MI can be folded to a stack operation, return // the register class to use. static const TargetRegisterClass *canFoldCopy(const MachineInstr *MI, @@ -217,8 +271,7 @@ static const TargetRegisterClass *canFoldCopy(const MachineInstr *MI, if (TargetRegisterInfo::isPhysicalRegister(LiveOp.getReg())) return RC->contains(LiveOp.getReg()) ? RC : 0; - const TargetRegisterClass *LiveRC = MRI.getRegClass(LiveReg); - if (RC == LiveRC || RC->hasSubClass(LiveRC)) + if (RC->hasSubClassEq(MRI.getRegClass(LiveReg))) return RC; // FIXME: Allow folding when register classes are memory compatible. @@ -253,51 +306,43 @@ TargetInstrInfo::foldMemoryOperand(MachineBasicBlock::iterator MI, MachineFunction &MF = *MBB->getParent(); // Ask the target to do the actual folding. - MachineInstr *NewMI = foldMemoryOperandImpl(MF, MI, Ops, FI); - - // Straight COPY may fold as load/store. - if (!NewMI) { - if (!MI->isCopy() || Ops.size() != 1) - return 0; + if (MachineInstr *NewMI = foldMemoryOperandImpl(MF, MI, Ops, FI)) { + // Add a memory operand, foldMemoryOperandImpl doesn't do that. + assert((!(Flags & MachineMemOperand::MOStore) || + NewMI->mayStore()) && + "Folded a def to a non-store!"); + assert((!(Flags & MachineMemOperand::MOLoad) || + NewMI->mayLoad()) && + "Folded a use to a non-load!"); + const MachineFrameInfo &MFI = *MF.getFrameInfo(); + assert(MFI.getObjectOffset(FI) != -1); + MachineMemOperand *MMO = + MF.getMachineMemOperand(MachinePointerInfo::getFixedStack(FI), + Flags, MFI.getObjectSize(FI), + MFI.getObjectAlignment(FI)); + NewMI->addMemOperand(MF, MMO); - const TargetRegisterClass *RC = canFoldCopy(MI, Ops[0]); - if (!RC) - return 0; - - const MachineOperand &MO = MI->getOperand(1-Ops[0]); - MachineBasicBlock::iterator Pos = MI; - const TargetRegisterInfo *TRI = MF.getTarget().getRegisterInfo(); - - if (Flags == MachineMemOperand::MOStore) - storeRegToStackSlot(*MBB, Pos, MO.getReg(), MO.isKill(), FI, RC, TRI); - else - loadRegFromStackSlot(*MBB, Pos, MO.getReg(), FI, RC, TRI); - - NewMI = --Pos; - } else { // FIXME: change foldMemoryOperandImpl semantics to also insert NewMI. - NewMI = MBB->insert(MI, NewMI); + return MBB->insert(MI, NewMI); } - if (!NewMI) return 0; + // Straight COPY may fold as load/store. + if (!MI->isCopy() || Ops.size() != 1) + return 0; + const TargetRegisterClass *RC = canFoldCopy(MI, Ops[0]); + if (!RC) + return 0; - assert((!(Flags & MachineMemOperand::MOStore) || - NewMI->getDesc().mayStore()) && - "Folded a def to a non-store!"); - assert((!(Flags & MachineMemOperand::MOLoad) || - NewMI->getDesc().mayLoad()) && - "Folded a use to a non-load!"); - const MachineFrameInfo &MFI = *MF.getFrameInfo(); - assert(MFI.getObjectOffset(FI) != -1); - MachineMemOperand *MMO = - MF.getMachineMemOperand(PseudoSourceValue::getFixedStack(FI), - Flags, /*Offset=*/0, - MFI.getObjectSize(FI), - MFI.getObjectAlignment(FI)); - NewMI->addMemOperand(MF, MMO); + const MachineOperand &MO = MI->getOperand(1-Ops[0]); + MachineBasicBlock::iterator Pos = MI; + const TargetRegisterInfo *TRI = MF.getTarget().getRegisterInfo(); - return NewMI; + if (Flags == MachineMemOperand::MOStore) + storeRegToStackSlot(*MBB, Pos, MO.getReg(), MO.isKill(), FI, RC, TRI); + else + loadRegFromStackSlot(*MBB, Pos, MO.getReg(), FI, RC, TRI); + return --Pos; } /// foldMemoryOperand - Same as the previous version except it allows folding @@ -307,7 +352,7 @@ MachineInstr* TargetInstrInfo::foldMemoryOperand(MachineBasicBlock::iterator MI, const SmallVectorImpl &Ops, MachineInstr* LoadMI) const { - assert(LoadMI->getDesc().canFoldAsLoad() && "LoadMI isn't foldable!"); + assert(LoadMI->canFoldAsLoad() && "LoadMI isn't foldable!"); #ifndef NDEBUG for (unsigned i = 0, e = Ops.size(); i != e; ++i) assert(MI->getOperand(Ops[i]).isUse() && "Folding load into def!"); @@ -335,7 +380,19 @@ isReallyTriviallyReMaterializableGeneric(const MachineInstr *MI, const MachineRegisterInfo &MRI = MF.getRegInfo(); const TargetMachine &TM = MF.getTarget(); const TargetInstrInfo &TII = *TM.getInstrInfo(); - const TargetRegisterInfo &TRI = *TM.getRegisterInfo(); + + // Remat clients assume operand 0 is the defined register. + if (!MI->getNumOperands() || !MI->getOperand(0).isReg()) + return false; + unsigned DefReg = MI->getOperand(0).getReg(); + + // A sub-register definition can only be rematerialized if the instruction + // doesn't read the other parts of the register. Otherwise it is really a + // read-modify-write operation on the full virtual register which cannot be + // moved safely. + if (TargetRegisterInfo::isVirtualRegister(DefReg) && + MI->getOperand(0).getSubReg() && MI->readsVirtualRegister(DefReg)) + return false; // A load from a fixed stack slot can be rematerialized. This may be // redundant with subsequent checks, but it's target-independent, @@ -345,15 +402,18 @@ isReallyTriviallyReMaterializableGeneric(const MachineInstr *MI, MF.getFrameInfo()->isImmutableObjectIndex(FrameIdx)) return true; - const TargetInstrDesc &TID = MI->getDesc(); - // Avoid instructions obviously unsafe for remat. - if (TID.hasUnmodeledSideEffects() || TID.isNotDuplicable() || - TID.mayStore()) + if (MI->isNotDuplicable() || MI->mayStore() || + MI->hasUnmodeledSideEffects()) + return false; + + // Don't remat inline asm. We have no idea how expensive it is + // even if it's side effect free. + if (MI->isInlineAsm()) return false; // Avoid instructions which load from potentially varying memory. - if (TID.mayLoad() && !MI->isInvariantLoad(AA)) + if (MI->mayLoad() && !MI->isInvariantLoad(AA)) return false; // If any of the registers accessed are non-constant, conservatively assume @@ -371,19 +431,8 @@ isReallyTriviallyReMaterializableGeneric(const MachineInstr *MI, // If the physreg has no defs anywhere, it's just an ambient register // and we can freely move its uses. Alternatively, if it's allocatable, // it could get allocated to something with a def during allocation. - if (!MRI.def_empty(Reg)) - return false; - BitVector AllocatableRegs = TRI.getAllocatableSet(MF, 0); - if (AllocatableRegs.test(Reg)) + if (!MRI.isConstantPhysReg(Reg, MF)) return false; - // Check for a def among the register's aliases too. - for (const unsigned *Alias = TRI.getAliasSet(Reg); *Alias; ++Alias) { - unsigned AliasReg = *Alias; - if (!MRI.def_empty(AliasReg)) - return false; - if (AllocatableRegs.test(AliasReg)) - return false; - } } else { // A physreg def. We can't remat it. return false; @@ -391,13 +440,9 @@ isReallyTriviallyReMaterializableGeneric(const MachineInstr *MI, continue; } - // Only allow one virtual-register def, and that in the first operand. - if (MO.isDef() != (i == 0)) - return false; - - // For the def, it should be the only def of that register. - if (MO.isDef() && (llvm::next(MRI.def_begin(Reg)) != MRI.def_end() || - MRI.isLiveIn(Reg))) + // Only allow one virtual-register def. There may be multiple defs of the + // same virtual register, though. + if (MO.isDef() && Reg != DefReg) return false; // Don't allow any virtual-register uses. Rematting an instruction with @@ -418,7 +463,7 @@ bool TargetInstrInfoImpl::isSchedulingBoundary(const MachineInstr *MI, const MachineBasicBlock *MBB, const MachineFunction &MF) const{ // Terminators and labels can't be scheduled around. - if (MI->getDesc().isTerminator() || MI->isLabel()) + if (MI->isTerminator() || MI->isLabel()) return true; // Don't attempt to schedule around any instruction that defines @@ -433,8 +478,202 @@ bool TargetInstrInfoImpl::isSchedulingBoundary(const MachineInstr *MI, return false; } +// Provide a global flag for disabling the PreRA hazard recognizer that targets +// may choose to honor. +bool TargetInstrInfoImpl::usePreRAHazardRecognizer() const { + return !DisableHazardRecognizer; +} + +// Default implementation of CreateTargetRAHazardRecognizer. +ScheduleHazardRecognizer *TargetInstrInfoImpl:: +CreateTargetHazardRecognizer(const TargetMachine *TM, + const ScheduleDAG *DAG) const { + // Dummy hazard recognizer allows all instructions to issue. + return new ScheduleHazardRecognizer(); +} + +// Default implementation of CreateTargetMIHazardRecognizer. +ScheduleHazardRecognizer *TargetInstrInfoImpl:: +CreateTargetMIHazardRecognizer(const InstrItineraryData *II, + const ScheduleDAG *DAG) const { + return (ScheduleHazardRecognizer *) + new ScoreboardHazardRecognizer(II, DAG, "misched"); +} + // Default implementation of CreateTargetPostRAHazardRecognizer. ScheduleHazardRecognizer *TargetInstrInfoImpl:: -CreateTargetPostRAHazardRecognizer(const InstrItineraryData &II) const { - return (ScheduleHazardRecognizer *)new PostRAHazardRecognizer(II); +CreateTargetPostRAHazardRecognizer(const InstrItineraryData *II, + const ScheduleDAG *DAG) const { + return (ScheduleHazardRecognizer *) + new ScoreboardHazardRecognizer(II, DAG, "post-RA-sched"); +} + +//===----------------------------------------------------------------------===// +// SelectionDAG latency interface. +//===----------------------------------------------------------------------===// + +int +TargetInstrInfoImpl::getOperandLatency(const InstrItineraryData *ItinData, + SDNode *DefNode, unsigned DefIdx, + SDNode *UseNode, unsigned UseIdx) const { + if (!ItinData || ItinData->isEmpty()) + return -1; + + if (!DefNode->isMachineOpcode()) + return -1; + + unsigned DefClass = get(DefNode->getMachineOpcode()).getSchedClass(); + if (!UseNode->isMachineOpcode()) + return ItinData->getOperandCycle(DefClass, DefIdx); + unsigned UseClass = get(UseNode->getMachineOpcode()).getSchedClass(); + return ItinData->getOperandLatency(DefClass, DefIdx, UseClass, UseIdx); +} + +int TargetInstrInfoImpl::getInstrLatency(const InstrItineraryData *ItinData, + SDNode *N) const { + if (!ItinData || ItinData->isEmpty()) + return 1; + + if (!N->isMachineOpcode()) + return 1; + + return ItinData->getStageLatency(get(N->getMachineOpcode()).getSchedClass()); +} + +//===----------------------------------------------------------------------===// +// MachineInstr latency interface. +//===----------------------------------------------------------------------===// + +unsigned +TargetInstrInfoImpl::getNumMicroOps(const InstrItineraryData *ItinData, + const MachineInstr *MI) const { + if (!ItinData || ItinData->isEmpty()) + return 1; + + unsigned Class = MI->getDesc().getSchedClass(); + int UOps = ItinData->Itineraries[Class].NumMicroOps; + if (UOps >= 0) + return UOps; + + // The # of u-ops is dynamically determined. The specific target should + // override this function to return the right number. + return 1; +} + +/// Return the default expected latency for a def based on it's opcode. +unsigned TargetInstrInfo::defaultDefLatency(const MCSchedModel *SchedModel, + const MachineInstr *DefMI) const { + if (DefMI->mayLoad()) + return SchedModel->LoadLatency; + if (isHighLatencyDef(DefMI->getOpcode())) + return SchedModel->HighLatency; + return 1; +} + +unsigned TargetInstrInfoImpl:: +getInstrLatency(const InstrItineraryData *ItinData, + const MachineInstr *MI, + unsigned *PredCost) const { + // Default to one cycle for no itinerary. However, an "empty" itinerary may + // still have a MinLatency property, which getStageLatency checks. + if (!ItinData) + return MI->mayLoad() ? 2 : 1; + + return ItinData->getStageLatency(MI->getDesc().getSchedClass()); +} + +bool TargetInstrInfoImpl::hasLowDefLatency(const InstrItineraryData *ItinData, + const MachineInstr *DefMI, + unsigned DefIdx) const { + if (!ItinData || ItinData->isEmpty()) + return false; + + unsigned DefClass = DefMI->getDesc().getSchedClass(); + int DefCycle = ItinData->getOperandCycle(DefClass, DefIdx); + return (DefCycle != -1 && DefCycle <= 1); +} + +/// Both DefMI and UseMI must be valid. By default, call directly to the +/// itinerary. This may be overriden by the target. +int TargetInstrInfoImpl:: +getOperandLatency(const InstrItineraryData *ItinData, + const MachineInstr *DefMI, unsigned DefIdx, + const MachineInstr *UseMI, unsigned UseIdx) const { + unsigned DefClass = DefMI->getDesc().getSchedClass(); + unsigned UseClass = UseMI->getDesc().getSchedClass(); + return ItinData->getOperandLatency(DefClass, DefIdx, UseClass, UseIdx); +} + +/// If we can determine the operand latency from the def only, without itinerary +/// lookup, do so. Otherwise return -1. +int TargetInstrInfo::computeDefOperandLatency( + const InstrItineraryData *ItinData, + const MachineInstr *DefMI, bool FindMin) const { + + // Let the target hook getInstrLatency handle missing itineraries. + if (!ItinData) + return getInstrLatency(ItinData, DefMI); + + // Return a latency based on the itinerary properties and defining instruction + // if possible. Some common subtargets don't require per-operand latency, + // especially for minimum latencies. + if (FindMin) { + // If MinLatency is valid, call getInstrLatency. This uses Stage latency if + // it exists before defaulting to MinLatency. + if (ItinData->SchedModel->MinLatency >= 0) + return getInstrLatency(ItinData, DefMI); + + // If MinLatency is invalid, OperandLatency is interpreted as MinLatency. + // For empty itineraries, short-cirtuit the check and default to one cycle. + if (ItinData->isEmpty()) + return 1; + } + else if(ItinData->isEmpty()) + return defaultDefLatency(ItinData->SchedModel, DefMI); + + // ...operand lookup required + return -1; +} + +/// computeOperandLatency - Compute and return the latency of the given data +/// dependent def and use when the operand indices are already known. UseMI may +/// be NULL for an unknown use. +/// +/// FindMin may be set to get the minimum vs. expected latency. Minimum +/// latency is used for scheduling groups, while expected latency is for +/// instruction cost and critical path. +/// +/// Depending on the subtarget's itinerary properties, this may or may not need +/// to call getOperandLatency(). For most subtargets, we don't need DefIdx or +/// UseIdx to compute min latency. +unsigned TargetInstrInfo:: +computeOperandLatency(const InstrItineraryData *ItinData, + const MachineInstr *DefMI, unsigned DefIdx, + const MachineInstr *UseMI, unsigned UseIdx, + bool FindMin) const { + + int DefLatency = computeDefOperandLatency(ItinData, DefMI, FindMin); + if (DefLatency >= 0) + return DefLatency; + + assert(ItinData && !ItinData->isEmpty() && "computeDefOperandLatency fail"); + + int OperLatency = 0; + if (UseMI) + OperLatency = getOperandLatency(ItinData, DefMI, DefIdx, UseMI, UseIdx); + else { + unsigned DefClass = DefMI->getDesc().getSchedClass(); + OperLatency = ItinData->getOperandCycle(DefClass, DefIdx); + } + if (OperLatency >= 0) + return OperLatency; + + // No operand latency was found. + unsigned InstrLatency = getInstrLatency(ItinData, DefMI); + + // Expected latency is the max of the stage latency and itinerary props. + if (!FindMin) + InstrLatency = std::max(InstrLatency, + defaultDefLatency(ItinData->SchedModel, DefMI)); + return InstrLatency; }