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

1 files changed, 659 insertions, 8 deletions

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 <cctype>
 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<bool> 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<MachineOperand, 0>(),
+                 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<MachineOperand> &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<const FixedStackPseudoSourceValue>((*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<const FixedStackPseudoSourceValue>((*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<unsigned> &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<unsigned> &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<unsigned> &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;
+}