From fa2d98632c77e5d9c305e97e5fa25d06f579127b Mon Sep 17 00:00:00 2001 From: Jakob Stoklund Olesen Date: Wed, 28 Nov 2012 02:35:13 +0000 Subject: Move the guts of TargetInstrInfoImpl into the TargetInstrInfo class. The *Impl class no longer serves a purpose now that the super-class implementation is in CodeGen. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168759 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/TargetInstrInfo.cpp | 667 +++++++++++++++++++++++++++++++++++++++- 1 file changed, 659 insertions(+), 8 deletions(-) (limited to 'lib/CodeGen/TargetInstrInfo.cpp') diff --git a/lib/CodeGen/TargetInstrInfo.cpp b/lib/CodeGen/TargetInstrInfo.cpp index f1d1d07c38..f949287421 100644 --- a/lib/CodeGen/TargetInstrInfo.cpp +++ b/lib/CodeGen/TargetInstrInfo.cpp @@ -12,20 +12,25 @@ //===----------------------------------------------------------------------===// #include "llvm/Target/TargetInstrInfo.h" -#include "llvm/Target/TargetRegisterInfo.h" +#include "llvm/CodeGen/MachineFrameInfo.h" +#include "llvm/CodeGen/MachineMemOperand.h" +#include "llvm/CodeGen/MachineRegisterInfo.h" +#include "llvm/CodeGen/PseudoSourceValue.h" +#include "llvm/CodeGen/ScoreboardHazardRecognizer.h" #include "llvm/MC/MCAsmInfo.h" #include "llvm/MC/MCInstrItineraries.h" +#include "llvm/Support/CommandLine.h" #include "llvm/Support/ErrorHandling.h" +#include "llvm/Support/raw_ostream.h" +#include "llvm/Target/TargetRegisterInfo.h" +#include "llvm/Target/TargetLowering.h" +#include "llvm/Target/TargetMachine.h" #include using namespace llvm; -//===----------------------------------------------------------------------===// -// TargetInstrInfo -// -// Methods that depend on CodeGen are implemented in -// TargetInstrInfoImpl.cpp. Invoking them without linking libCodeGen raises a -// link error. -// ===----------------------------------------------------------------------===// +static cl::opt DisableHazardRecognizer( + "disable-sched-hazard", cl::Hidden, cl::init(false), + cl::desc("Disable hazard detection during preRA scheduling")); TargetInstrInfo::~TargetInstrInfo() { } @@ -86,3 +91,649 @@ unsigned TargetInstrInfo::getInlineAsmLength(const char *Str, return Length; } + +/// ReplaceTailWithBranchTo - Delete the instruction OldInst and everything +/// after it, replacing it with an unconditional branch to NewDest. +void +TargetInstrInfo::ReplaceTailWithBranchTo(MachineBasicBlock::iterator Tail, + MachineBasicBlock *NewDest) const { + MachineBasicBlock *MBB = Tail->getParent(); + + // Remove all the old successors of MBB from the CFG. + while (!MBB->succ_empty()) + MBB->removeSuccessor(MBB->succ_begin()); + + // Remove all the dead instructions from the end of MBB. + MBB->erase(Tail, MBB->end()); + + // If MBB isn't immediately before MBB, insert a branch to it. + if (++MachineFunction::iterator(MBB) != MachineFunction::iterator(NewDest)) + InsertBranch(*MBB, NewDest, 0, SmallVector(), + Tail->getDebugLoc()); + MBB->addSuccessor(NewDest); +} + +// commuteInstruction - The default implementation of this method just exchanges +// the two operands returned by findCommutedOpIndices. +MachineInstr *TargetInstrInfo::commuteInstruction(MachineInstr *MI, + bool NewMI) const { + 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; + unsigned Idx1, Idx2; + if (!findCommutedOpIndices(MI, Idx1, Idx2)) { + std::string msg; + raw_string_ostream Msg(msg); + Msg << "Don't know how to commute: " << *MI; + report_fatal_error(Msg.str()); + } + + 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(); + // 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; + 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. + MachineFunction &MF = *MI->getParent()->getParent(); + MI = MF.CloneMachineInstr(MI); + } + + 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; +} + +/// findCommutedOpIndices - If specified MI is commutable, return the two +/// operand indices that would swap value. Return true if the instruction +/// is not in a form which this routine understands. +bool TargetInstrInfo::findCommutedOpIndices(MachineInstr *MI, + unsigned &SrcOpIdx1, + unsigned &SrcOpIdx2) const { + assert(!MI->isBundle() && + "TargetInstrInfo::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 = MCID.getNumDefs(); + SrcOpIdx2 = SrcOpIdx1 + 1; + if (!MI->getOperand(SrcOpIdx1).isReg() || + !MI->getOperand(SrcOpIdx2).isReg()) + // No idea. + return false; + return true; +} + + +bool +TargetInstrInfo::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 TargetInstrInfo::PredicateInstruction(MachineInstr *MI, + const SmallVectorImpl &Pred) const { + bool MadeChange = false; + + assert(!MI->isBundle() && + "TargetInstrInfo::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 (MCID.OpInfo[i].isPredicate()) { + MachineOperand &MO = MI->getOperand(i); + if (MO.isReg()) { + MO.setReg(Pred[j].getReg()); + MadeChange = true; + } else if (MO.isImm()) { + MO.setImm(Pred[j].getImm()); + MadeChange = true; + } else if (MO.isMBB()) { + MO.setMBB(Pred[j].getMBB()); + MadeChange = true; + } + ++j; + } + } + return MadeChange; +} + +bool TargetInstrInfo::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 TargetInstrInfo::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 TargetInstrInfo::reMaterialize(MachineBasicBlock &MBB, + MachineBasicBlock::iterator I, + unsigned DestReg, + unsigned SubIdx, + const MachineInstr *Orig, + const TargetRegisterInfo &TRI) const { + MachineInstr *MI = MBB.getParent()->CloneMachineInstr(Orig); + MI->substituteRegister(MI->getOperand(0).getReg(), DestReg, SubIdx, TRI); + MBB.insert(I, MI); +} + +bool +TargetInstrInfo::produceSameValue(const MachineInstr *MI0, + const MachineInstr *MI1, + const MachineRegisterInfo *MRI) const { + return MI0->isIdenticalTo(MI1, MachineInstr::IgnoreVRegDefs); +} + +MachineInstr *TargetInstrInfo::duplicate(MachineInstr *Orig, + MachineFunction &MF) const { + assert(!Orig->isNotDuplicable() && + "Instruction cannot be duplicated"); + return MF.CloneMachineInstr(Orig); +} + +// 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, + unsigned FoldIdx) { + assert(MI->isCopy() && "MI must be a COPY instruction"); + if (MI->getNumOperands() != 2) + return 0; + assert(FoldIdx<2 && "FoldIdx refers no nonexistent operand"); + + const MachineOperand &FoldOp = MI->getOperand(FoldIdx); + const MachineOperand &LiveOp = MI->getOperand(1-FoldIdx); + + if (FoldOp.getSubReg() || LiveOp.getSubReg()) + return 0; + + unsigned FoldReg = FoldOp.getReg(); + unsigned LiveReg = LiveOp.getReg(); + + assert(TargetRegisterInfo::isVirtualRegister(FoldReg) && + "Cannot fold physregs"); + + const MachineRegisterInfo &MRI = MI->getParent()->getParent()->getRegInfo(); + const TargetRegisterClass *RC = MRI.getRegClass(FoldReg); + + if (TargetRegisterInfo::isPhysicalRegister(LiveOp.getReg())) + return RC->contains(LiveOp.getReg()) ? RC : 0; + + if (RC->hasSubClassEq(MRI.getRegClass(LiveReg))) + return RC; + + // FIXME: Allow folding when register classes are memory compatible. + return 0; +} + +bool TargetInstrInfo:: +canFoldMemoryOperand(const MachineInstr *MI, + const SmallVectorImpl &Ops) const { + return MI->isCopy() && Ops.size() == 1 && canFoldCopy(MI, Ops[0]); +} + +/// foldMemoryOperand - Attempt to fold a load or store of the specified stack +/// slot into the specified machine instruction for the specified operand(s). +/// If this is possible, a new instruction is returned with the specified +/// operand folded, otherwise NULL is returned. The client is responsible for +/// removing the old instruction and adding the new one in the instruction +/// stream. +MachineInstr* +TargetInstrInfo::foldMemoryOperand(MachineBasicBlock::iterator MI, + const SmallVectorImpl &Ops, + int FI) const { + unsigned Flags = 0; + for (unsigned i = 0, e = Ops.size(); i != e; ++i) + if (MI->getOperand(Ops[i]).isDef()) + Flags |= MachineMemOperand::MOStore; + else + Flags |= MachineMemOperand::MOLoad; + + MachineBasicBlock *MBB = MI->getParent(); + assert(MBB && "foldMemoryOperand needs an inserted instruction"); + MachineFunction &MF = *MBB->getParent(); + + // Ask the target to do the actual folding. + 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); + + // FIXME: change foldMemoryOperandImpl semantics to also insert NewMI. + return MBB->insert(MI, NewMI); + } + + // 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; + + 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); + return --Pos; +} + +/// foldMemoryOperand - Same as the previous version except it allows folding +/// of any load and store from / to any address, not just from a specific +/// stack slot. +MachineInstr* +TargetInstrInfo::foldMemoryOperand(MachineBasicBlock::iterator MI, + const SmallVectorImpl &Ops, + MachineInstr* LoadMI) const { + 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!"); +#endif + MachineBasicBlock &MBB = *MI->getParent(); + MachineFunction &MF = *MBB.getParent(); + + // Ask the target to do the actual folding. + MachineInstr *NewMI = foldMemoryOperandImpl(MF, MI, Ops, LoadMI); + if (!NewMI) return 0; + + NewMI = MBB.insert(MI, NewMI); + + // Copy the memoperands from the load to the folded instruction. + NewMI->setMemRefs(LoadMI->memoperands_begin(), + LoadMI->memoperands_end()); + + return NewMI; +} + +bool TargetInstrInfo:: +isReallyTriviallyReMaterializableGeneric(const MachineInstr *MI, + AliasAnalysis *AA) const { + const MachineFunction &MF = *MI->getParent()->getParent(); + const MachineRegisterInfo &MRI = MF.getRegInfo(); + const TargetMachine &TM = MF.getTarget(); + const TargetInstrInfo &TII = *TM.getInstrInfo(); + + // 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, + // simple, and a common case. + int FrameIdx = 0; + if (TII.isLoadFromStackSlot(MI, FrameIdx) && + MF.getFrameInfo()->isImmutableObjectIndex(FrameIdx)) + return true; + + // Avoid instructions obviously unsafe for remat. + 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 (MI->mayLoad() && !MI->isInvariantLoad(AA)) + return false; + + // If any of the registers accessed are non-constant, conservatively assume + // the instruction is not rematerializable. + for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) { + const MachineOperand &MO = MI->getOperand(i); + if (!MO.isReg()) continue; + unsigned Reg = MO.getReg(); + if (Reg == 0) + continue; + + // Check for a well-behaved physical register. + if (TargetRegisterInfo::isPhysicalRegister(Reg)) { + if (MO.isUse()) { + // 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.isConstantPhysReg(Reg, MF)) + return false; + } else { + // A physreg def. We can't remat it. + return false; + } + continue; + } + + // 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 + // virtual register uses would length the live ranges of the uses, which + // is not necessarily a good idea, certainly not "trivial". + if (MO.isUse()) + return false; + } + + // Everything checked out. + return true; +} + +/// isSchedulingBoundary - Test if the given instruction should be +/// considered a scheduling boundary. This primarily includes labels +/// and terminators. +bool TargetInstrInfo::isSchedulingBoundary(const MachineInstr *MI, + const MachineBasicBlock *MBB, + const MachineFunction &MF) const { + // Terminators and labels can't be scheduled around. + if (MI->isTerminator() || MI->isLabel()) + return true; + + // Don't attempt to schedule around any instruction that defines + // a stack-oriented pointer, as it's unlikely to be profitable. This + // saves compile time, because it doesn't require every single + // stack slot reference to depend on the instruction that does the + // modification. + const TargetLowering &TLI = *MF.getTarget().getTargetLowering(); + const TargetRegisterInfo *TRI = MF.getTarget().getRegisterInfo(); + if (MI->modifiesRegister(TLI.getStackPointerRegisterToSaveRestore(), TRI)) + return true; + + return false; +} + +// Provide a global flag for disabling the PreRA hazard recognizer that targets +// may choose to honor. +bool TargetInstrInfo::usePreRAHazardRecognizer() const { + return !DisableHazardRecognizer; +} + +// Default implementation of CreateTargetRAHazardRecognizer. +ScheduleHazardRecognizer *TargetInstrInfo:: +CreateTargetHazardRecognizer(const TargetMachine *TM, + const ScheduleDAG *DAG) const { + // Dummy hazard recognizer allows all instructions to issue. + return new ScheduleHazardRecognizer(); +} + +// Default implementation of CreateTargetMIHazardRecognizer. +ScheduleHazardRecognizer *TargetInstrInfo:: +CreateTargetMIHazardRecognizer(const InstrItineraryData *II, + const ScheduleDAG *DAG) const { + return (ScheduleHazardRecognizer *) + new ScoreboardHazardRecognizer(II, DAG, "misched"); +} + +// Default implementation of CreateTargetPostRAHazardRecognizer. +ScheduleHazardRecognizer *TargetInstrInfo:: +CreateTargetPostRAHazardRecognizer(const InstrItineraryData *II, + const ScheduleDAG *DAG) const { + return (ScheduleHazardRecognizer *) + new ScoreboardHazardRecognizer(II, DAG, "post-RA-sched"); +} + +//===----------------------------------------------------------------------===// +// SelectionDAG latency interface. +//===----------------------------------------------------------------------===// + +int +TargetInstrInfo::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 TargetInstrInfo::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 +TargetInstrInfo::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->isTransient()) + return 0; + if (DefMI->mayLoad()) + return SchedModel->LoadLatency; + if (isHighLatencyDef(DefMI->getOpcode())) + return SchedModel->HighLatency; + return 1; +} + +unsigned TargetInstrInfo:: +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 TargetInstrInfo::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 TargetInstrInfo:: +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; +} -- cgit v1.2.3