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diff --git a/contrib/llvm-project/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp b/contrib/llvm-project/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp
new file mode 100644
index 000000000000..e09f2e760f55
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+++ b/contrib/llvm-project/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp
@@ -0,0 +1,1033 @@
+//===--- ScheduleDAGSDNodes.cpp - Implement the ScheduleDAGSDNodes class --===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This implements the ScheduleDAG class, which is a base class used by
+// scheduling implementation classes.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ScheduleDAGSDNodes.h"
+#include "InstrEmitter.h"
+#include "SDNodeDbgValue.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/SmallSet.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/CodeGen/SelectionDAG.h"
+#include "llvm/CodeGen/TargetInstrInfo.h"
+#include "llvm/CodeGen/TargetLowering.h"
+#include "llvm/CodeGen/TargetRegisterInfo.h"
+#include "llvm/CodeGen/TargetSubtargetInfo.h"
+#include "llvm/Config/llvm-config.h"
+#include "llvm/MC/MCInstrItineraries.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
+using namespace llvm;
+
+#define DEBUG_TYPE "pre-RA-sched"
+
+STATISTIC(LoadsClustered, "Number of loads clustered together");
+
+// This allows the latency-based scheduler to notice high latency instructions
+// without a target itinerary. The choice of number here has more to do with
+// balancing scheduler heuristics than with the actual machine latency.
+static cl::opt<int> HighLatencyCycles(
+  "sched-high-latency-cycles", cl::Hidden, cl::init(10),
+  cl::desc("Roughly estimate the number of cycles that 'long latency'"
+           "instructions take for targets with no itinerary"));
+
+ScheduleDAGSDNodes::ScheduleDAGSDNodes(MachineFunction &mf)
+    : ScheduleDAG(mf), BB(nullptr), DAG(nullptr),
+      InstrItins(mf.getSubtarget().getInstrItineraryData()) {}
+
+/// Run - perform scheduling.
+///
+void ScheduleDAGSDNodes::Run(SelectionDAG *dag, MachineBasicBlock *bb) {
+  BB = bb;
+  DAG = dag;
+
+  // Clear the scheduler's SUnit DAG.
+  ScheduleDAG::clearDAG();
+  Sequence.clear();
+
+  // Invoke the target's selection of scheduler.
+  Schedule();
+}
+
+/// NewSUnit - Creates a new SUnit and return a ptr to it.
+///
+SUnit *ScheduleDAGSDNodes::newSUnit(SDNode *N) {
+#ifndef NDEBUG
+  const SUnit *Addr = nullptr;
+  if (!SUnits.empty())
+    Addr = &SUnits[0];
+#endif
+  SUnits.emplace_back(N, (unsigned)SUnits.size());
+  assert((Addr == nullptr || Addr == &SUnits[0]) &&
+         "SUnits std::vector reallocated on the fly!");
+  SUnits.back().OrigNode = &SUnits.back();
+  SUnit *SU = &SUnits.back();
+  const TargetLowering &TLI = DAG->getTargetLoweringInfo();
+  if (!N ||
+      (N->isMachineOpcode() &&
+       N->getMachineOpcode() == TargetOpcode::IMPLICIT_DEF))
+    SU->SchedulingPref = Sched::None;
+  else
+    SU->SchedulingPref = TLI.getSchedulingPreference(N);
+  return SU;
+}
+
+SUnit *ScheduleDAGSDNodes::Clone(SUnit *Old) {
+  SUnit *SU = newSUnit(Old->getNode());
+  SU->OrigNode = Old->OrigNode;
+  SU->Latency = Old->Latency;
+  SU->isVRegCycle = Old->isVRegCycle;
+  SU->isCall = Old->isCall;
+  SU->isCallOp = Old->isCallOp;
+  SU->isTwoAddress = Old->isTwoAddress;
+  SU->isCommutable = Old->isCommutable;
+  SU->hasPhysRegDefs = Old->hasPhysRegDefs;
+  SU->hasPhysRegClobbers = Old->hasPhysRegClobbers;
+  SU->isScheduleHigh = Old->isScheduleHigh;
+  SU->isScheduleLow = Old->isScheduleLow;
+  SU->SchedulingPref = Old->SchedulingPref;
+  Old->isCloned = true;
+  return SU;
+}
+
+/// CheckForPhysRegDependency - Check if the dependency between def and use of
+/// a specified operand is a physical register dependency. If so, returns the
+/// register and the cost of copying the register.
+static void CheckForPhysRegDependency(SDNode *Def, SDNode *User, unsigned Op,
+                                      const TargetRegisterInfo *TRI,
+                                      const TargetInstrInfo *TII,
+                                      unsigned &PhysReg, int &Cost) {
+  if (Op != 2 || User->getOpcode() != ISD::CopyToReg)
+    return;
+
+  unsigned Reg = cast<RegisterSDNode>(User->getOperand(1))->getReg();
+  if (TargetRegisterInfo::isVirtualRegister(Reg))
+    return;
+
+  unsigned ResNo = User->getOperand(2).getResNo();
+  if (Def->getOpcode() == ISD::CopyFromReg &&
+      cast<RegisterSDNode>(Def->getOperand(1))->getReg() == Reg) {
+    PhysReg = Reg;
+  } else if (Def->isMachineOpcode()) {
+    const MCInstrDesc &II = TII->get(Def->getMachineOpcode());
+    if (ResNo >= II.getNumDefs() &&
+        II.ImplicitDefs[ResNo - II.getNumDefs()] == Reg)
+      PhysReg = Reg;
+  }
+
+  if (PhysReg != 0) {
+    const TargetRegisterClass *RC =
+        TRI->getMinimalPhysRegClass(Reg, Def->getSimpleValueType(ResNo));
+    Cost = RC->getCopyCost();
+  }
+}
+
+// Helper for AddGlue to clone node operands.
+static void CloneNodeWithValues(SDNode *N, SelectionDAG *DAG, ArrayRef<EVT> VTs,
+                                SDValue ExtraOper = SDValue()) {
+  SmallVector<SDValue, 8> Ops(N->op_begin(), N->op_end());
+  if (ExtraOper.getNode())
+    Ops.push_back(ExtraOper);
+
+  SDVTList VTList = DAG->getVTList(VTs);
+  MachineSDNode *MN = dyn_cast<MachineSDNode>(N);
+
+  // Store memory references.
+  SmallVector<MachineMemOperand *, 2> MMOs;
+  if (MN)
+    MMOs.assign(MN->memoperands_begin(), MN->memoperands_end());
+
+  DAG->MorphNodeTo(N, N->getOpcode(), VTList, Ops);
+
+  // Reset the memory references
+  if (MN)
+    DAG->setNodeMemRefs(MN, MMOs);
+}
+
+static bool AddGlue(SDNode *N, SDValue Glue, bool AddGlue, SelectionDAG *DAG) {
+  SDNode *GlueDestNode = Glue.getNode();
+
+  // Don't add glue from a node to itself.
+  if (GlueDestNode == N) return false;
+
+  // Don't add a glue operand to something that already uses glue.
+  if (GlueDestNode &&
+      N->getOperand(N->getNumOperands()-1).getValueType() == MVT::Glue) {
+    return false;
+  }
+  // Don't add glue to something that already has a glue value.
+  if (N->getValueType(N->getNumValues() - 1) == MVT::Glue) return false;
+
+  SmallVector<EVT, 4> VTs(N->value_begin(), N->value_end());
+  if (AddGlue)
+    VTs.push_back(MVT::Glue);
+
+  CloneNodeWithValues(N, DAG, VTs, Glue);
+
+  return true;
+}
+
+// Cleanup after unsuccessful AddGlue. Use the standard method of morphing the
+// node even though simply shrinking the value list is sufficient.
+static void RemoveUnusedGlue(SDNode *N, SelectionDAG *DAG) {
+  assert((N->getValueType(N->getNumValues() - 1) == MVT::Glue &&
+          !N->hasAnyUseOfValue(N->getNumValues() - 1)) &&
+         "expected an unused glue value");
+
+  CloneNodeWithValues(N, DAG,
+                      makeArrayRef(N->value_begin(), N->getNumValues() - 1));
+}
+
+/// ClusterNeighboringLoads - Force nearby loads together by "gluing" them.
+/// This function finds loads of the same base and different offsets. If the
+/// offsets are not far apart (target specific), it add MVT::Glue inputs and
+/// outputs to ensure they are scheduled together and in order. This
+/// optimization may benefit some targets by improving cache locality.
+void ScheduleDAGSDNodes::ClusterNeighboringLoads(SDNode *Node) {
+  SDNode *Chain = nullptr;
+  unsigned NumOps = Node->getNumOperands();
+  if (Node->getOperand(NumOps-1).getValueType() == MVT::Other)
+    Chain = Node->getOperand(NumOps-1).getNode();
+  if (!Chain)
+    return;
+
+  // Skip any load instruction that has a tied input. There may be an additional
+  // dependency requiring a different order than by increasing offsets, and the
+  // added glue may introduce a cycle.
+  auto hasTiedInput = [this](const SDNode *N) {
+    const MCInstrDesc &MCID = TII->get(N->getMachineOpcode());
+    for (unsigned I = 0; I != MCID.getNumOperands(); ++I) {
+      if (MCID.getOperandConstraint(I, MCOI::TIED_TO) != -1)
+        return true;
+    }
+
+    return false;
+  };
+
+  // Look for other loads of the same chain. Find loads that are loading from
+  // the same base pointer and different offsets.
+  SmallPtrSet<SDNode*, 16> Visited;
+  SmallVector<int64_t, 4> Offsets;
+  DenseMap<long long, SDNode*> O2SMap;  // Map from offset to SDNode.
+  bool Cluster = false;
+  SDNode *Base = Node;
+
+  if (hasTiedInput(Base))
+    return;
+
+  // This algorithm requires a reasonably low use count before finding a match
+  // to avoid uselessly blowing up compile time in large blocks.
+  unsigned UseCount = 0;
+  for (SDNode::use_iterator I = Chain->use_begin(), E = Chain->use_end();
+       I != E && UseCount < 100; ++I, ++UseCount) {
+    SDNode *User = *I;
+    if (User == Node || !Visited.insert(User).second)
+      continue;
+    int64_t Offset1, Offset2;
+    if (!TII->areLoadsFromSameBasePtr(Base, User, Offset1, Offset2) ||
+        Offset1 == Offset2 ||
+        hasTiedInput(User)) {
+      // FIXME: Should be ok if they addresses are identical. But earlier
+      // optimizations really should have eliminated one of the loads.
+      continue;
+    }
+    if (O2SMap.insert(std::make_pair(Offset1, Base)).second)
+      Offsets.push_back(Offset1);
+    O2SMap.insert(std::make_pair(Offset2, User));
+    Offsets.push_back(Offset2);
+    if (Offset2 < Offset1)
+      Base = User;
+    Cluster = true;
+    // Reset UseCount to allow more matches.
+    UseCount = 0;
+  }
+
+  if (!Cluster)
+    return;
+
+  // Sort them in increasing order.
+  llvm::sort(Offsets);
+
+  // Check if the loads are close enough.
+  SmallVector<SDNode*, 4> Loads;
+  unsigned NumLoads = 0;
+  int64_t BaseOff = Offsets[0];
+  SDNode *BaseLoad = O2SMap[BaseOff];
+  Loads.push_back(BaseLoad);
+  for (unsigned i = 1, e = Offsets.size(); i != e; ++i) {
+    int64_t Offset = Offsets[i];
+    SDNode *Load = O2SMap[Offset];
+    if (!TII->shouldScheduleLoadsNear(BaseLoad, Load, BaseOff, Offset,NumLoads))
+      break; // Stop right here. Ignore loads that are further away.
+    Loads.push_back(Load);
+    ++NumLoads;
+  }
+
+  if (NumLoads == 0)
+    return;
+
+  // Cluster loads by adding MVT::Glue outputs and inputs. This also
+  // ensure they are scheduled in order of increasing addresses.
+  SDNode *Lead = Loads[0];
+  SDValue InGlue = SDValue(nullptr, 0);
+  if (AddGlue(Lead, InGlue, true, DAG))
+    InGlue = SDValue(Lead, Lead->getNumValues() - 1);
+  for (unsigned I = 1, E = Loads.size(); I != E; ++I) {
+    bool OutGlue = I < E - 1;
+    SDNode *Load = Loads[I];
+
+    // If AddGlue fails, we could leave an unsused glue value. This should not
+    // cause any
+    if (AddGlue(Load, InGlue, OutGlue, DAG)) {
+      if (OutGlue)
+        InGlue = SDValue(Load, Load->getNumValues() - 1);
+
+      ++LoadsClustered;
+    }
+    else if (!OutGlue && InGlue.getNode())
+      RemoveUnusedGlue(InGlue.getNode(), DAG);
+  }
+}
+
+/// ClusterNodes - Cluster certain nodes which should be scheduled together.
+///
+void ScheduleDAGSDNodes::ClusterNodes() {
+  for (SDNode &NI : DAG->allnodes()) {
+    SDNode *Node = &NI;
+    if (!Node || !Node->isMachineOpcode())
+      continue;
+
+    unsigned Opc = Node->getMachineOpcode();
+    const MCInstrDesc &MCID = TII->get(Opc);
+    if (MCID.mayLoad())
+      // Cluster loads from "near" addresses into combined SUnits.
+      ClusterNeighboringLoads(Node);
+  }
+}
+
+void ScheduleDAGSDNodes::BuildSchedUnits() {
+  // During scheduling, the NodeId field of SDNode is used to map SDNodes
+  // to their associated SUnits by holding SUnits table indices. A value
+  // of -1 means the SDNode does not yet have an associated SUnit.
+  unsigned NumNodes = 0;
+  for (SDNode &NI : DAG->allnodes()) {
+    NI.setNodeId(-1);
+    ++NumNodes;
+  }
+
+  // Reserve entries in the vector for each of the SUnits we are creating.  This
+  // ensure that reallocation of the vector won't happen, so SUnit*'s won't get
+  // invalidated.
+  // FIXME: Multiply by 2 because we may clone nodes during scheduling.
+  // This is a temporary workaround.
+  SUnits.reserve(NumNodes * 2);
+
+  // Add all nodes in depth first order.
+  SmallVector<SDNode*, 64> Worklist;
+  SmallPtrSet<SDNode*, 32> Visited;
+  Worklist.push_back(DAG->getRoot().getNode());
+  Visited.insert(DAG->getRoot().getNode());
+
+  SmallVector<SUnit*, 8> CallSUnits;
+  while (!Worklist.empty()) {
+    SDNode *NI = Worklist.pop_back_val();
+
+    // Add all operands to the worklist unless they've already been added.
+    for (const SDValue &Op : NI->op_values())
+      if (Visited.insert(Op.getNode()).second)
+        Worklist.push_back(Op.getNode());
+
+    if (isPassiveNode(NI))  // Leaf node, e.g. a TargetImmediate.
+      continue;
+
+    // If this node has already been processed, stop now.
+    if (NI->getNodeId() != -1) continue;
+
+    SUnit *NodeSUnit = newSUnit(NI);
+
+    // See if anything is glued to this node, if so, add them to glued
+    // nodes.  Nodes can have at most one glue input and one glue output.  Glue
+    // is required to be the last operand and result of a node.
+
+    // Scan up to find glued preds.
+    SDNode *N = NI;
+    while (N->getNumOperands() &&
+           N->getOperand(N->getNumOperands()-1).getValueType() == MVT::Glue) {
+      N = N->getOperand(N->getNumOperands()-1).getNode();
+      assert(N->getNodeId() == -1 && "Node already inserted!");
+      N->setNodeId(NodeSUnit->NodeNum);
+      if (N->isMachineOpcode() && TII->get(N->getMachineOpcode()).isCall())
+        NodeSUnit->isCall = true;
+    }
+
+    // Scan down to find any glued succs.
+    N = NI;
+    while (N->getValueType(N->getNumValues()-1) == MVT::Glue) {
+      SDValue GlueVal(N, N->getNumValues()-1);
+
+      // There are either zero or one users of the Glue result.
+      bool HasGlueUse = false;
+      for (SDNode::use_iterator UI = N->use_begin(), E = N->use_end();
+           UI != E; ++UI)
+        if (GlueVal.isOperandOf(*UI)) {
+          HasGlueUse = true;
+          assert(N->getNodeId() == -1 && "Node already inserted!");
+          N->setNodeId(NodeSUnit->NodeNum);
+          N = *UI;
+          if (N->isMachineOpcode() && TII->get(N->getMachineOpcode()).isCall())
+            NodeSUnit->isCall = true;
+          break;
+        }
+      if (!HasGlueUse) break;
+    }
+
+    if (NodeSUnit->isCall)
+      CallSUnits.push_back(NodeSUnit);
+
+    // Schedule zero-latency TokenFactor below any nodes that may increase the
+    // schedule height. Otherwise, ancestors of the TokenFactor may appear to
+    // have false stalls.
+    if (NI->getOpcode() == ISD::TokenFactor)
+      NodeSUnit->isScheduleLow = true;
+
+    // If there are glue operands involved, N is now the bottom-most node
+    // of the sequence of nodes that are glued together.
+    // Update the SUnit.
+    NodeSUnit->setNode(N);
+    assert(N->getNodeId() == -1 && "Node already inserted!");
+    N->setNodeId(NodeSUnit->NodeNum);
+
+    // Compute NumRegDefsLeft. This must be done before AddSchedEdges.
+    InitNumRegDefsLeft(NodeSUnit);
+
+    // Assign the Latency field of NodeSUnit using target-provided information.
+    computeLatency(NodeSUnit);
+  }
+
+  // Find all call operands.
+  while (!CallSUnits.empty()) {
+    SUnit *SU = CallSUnits.pop_back_val();
+    for (const SDNode *SUNode = SU->getNode(); SUNode;
+         SUNode = SUNode->getGluedNode()) {
+      if (SUNode->getOpcode() != ISD::CopyToReg)
+        continue;
+      SDNode *SrcN = SUNode->getOperand(2).getNode();
+      if (isPassiveNode(SrcN)) continue;   // Not scheduled.
+      SUnit *SrcSU = &SUnits[SrcN->getNodeId()];
+      SrcSU->isCallOp = true;
+    }
+  }
+}
+
+void ScheduleDAGSDNodes::AddSchedEdges() {
+  const TargetSubtargetInfo &ST = MF.getSubtarget();
+
+  // Check to see if the scheduler cares about latencies.
+  bool UnitLatencies = forceUnitLatencies();
+
+  // Pass 2: add the preds, succs, etc.
+  for (unsigned su = 0, e = SUnits.size(); su != e; ++su) {
+    SUnit *SU = &SUnits[su];
+    SDNode *MainNode = SU->getNode();
+
+    if (MainNode->isMachineOpcode()) {
+      unsigned Opc = MainNode->getMachineOpcode();
+      const MCInstrDesc &MCID = TII->get(Opc);
+      for (unsigned i = 0; i != MCID.getNumOperands(); ++i) {
+        if (MCID.getOperandConstraint(i, MCOI::TIED_TO) != -1) {
+          SU->isTwoAddress = true;
+          break;
+        }
+      }
+      if (MCID.isCommutable())
+        SU->isCommutable = true;
+    }
+
+    // Find all predecessors and successors of the group.
+    for (SDNode *N = SU->getNode(); N; N = N->getGluedNode()) {
+      if (N->isMachineOpcode() &&
+          TII->get(N->getMachineOpcode()).getImplicitDefs()) {
+        SU->hasPhysRegClobbers = true;
+        unsigned NumUsed = InstrEmitter::CountResults(N);
+        while (NumUsed != 0 && !N->hasAnyUseOfValue(NumUsed - 1))
+          --NumUsed;    // Skip over unused values at the end.
+        if (NumUsed > TII->get(N->getMachineOpcode()).getNumDefs())
+          SU->hasPhysRegDefs = true;
+      }
+
+      for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
+        SDNode *OpN = N->getOperand(i).getNode();
+        if (isPassiveNode(OpN)) continue;   // Not scheduled.
+        SUnit *OpSU = &SUnits[OpN->getNodeId()];
+        assert(OpSU && "Node has no SUnit!");
+        if (OpSU == SU) continue;           // In the same group.
+
+        EVT OpVT = N->getOperand(i).getValueType();
+        assert(OpVT != MVT::Glue && "Glued nodes should be in same sunit!");
+        bool isChain = OpVT == MVT::Other;
+
+        unsigned PhysReg = 0;
+        int Cost = 1;
+        // Determine if this is a physical register dependency.
+        CheckForPhysRegDependency(OpN, N, i, TRI, TII, PhysReg, Cost);
+        assert((PhysReg == 0 || !isChain) &&
+               "Chain dependence via physreg data?");
+        // FIXME: See ScheduleDAGSDNodes::EmitCopyFromReg. For now, scheduler
+        // emits a copy from the physical register to a virtual register unless
+        // it requires a cross class copy (cost < 0). That means we are only
+        // treating "expensive to copy" register dependency as physical register
+        // dependency. This may change in the future though.
+        if (Cost >= 0 && !StressSched)
+          PhysReg = 0;
+
+        // If this is a ctrl dep, latency is 1.
+        unsigned OpLatency = isChain ? 1 : OpSU->Latency;
+        // Special-case TokenFactor chains as zero-latency.
+        if(isChain && OpN->getOpcode() == ISD::TokenFactor)
+          OpLatency = 0;
+
+        SDep Dep = isChain ? SDep(OpSU, SDep::Barrier)
+          : SDep(OpSU, SDep::Data, PhysReg);
+        Dep.setLatency(OpLatency);
+        if (!isChain && !UnitLatencies) {
+          computeOperandLatency(OpN, N, i, Dep);
+          ST.adjustSchedDependency(OpSU, SU, Dep);
+        }
+
+        if (!SU->addPred(Dep) && !Dep.isCtrl() && OpSU->NumRegDefsLeft > 1) {
+          // Multiple register uses are combined in the same SUnit. For example,
+          // we could have a set of glued nodes with all their defs consumed by
+          // another set of glued nodes. Register pressure tracking sees this as
+          // a single use, so to keep pressure balanced we reduce the defs.
+          //
+          // We can't tell (without more book-keeping) if this results from
+          // glued nodes or duplicate operands. As long as we don't reduce
+          // NumRegDefsLeft to zero, we handle the common cases well.
+          --OpSU->NumRegDefsLeft;
+        }
+      }
+    }
+  }
+}
+
+/// BuildSchedGraph - Build the SUnit graph from the selection dag that we
+/// are input.  This SUnit graph is similar to the SelectionDAG, but
+/// excludes nodes that aren't interesting to scheduling, and represents
+/// glued together nodes with a single SUnit.
+void ScheduleDAGSDNodes::BuildSchedGraph(AliasAnalysis *AA) {
+  // Cluster certain nodes which should be scheduled together.
+  ClusterNodes();
+  // Populate the SUnits array.
+  BuildSchedUnits();
+  // Compute all the scheduling dependencies between nodes.
+  AddSchedEdges();
+}
+
+// Initialize NumNodeDefs for the current Node's opcode.
+void ScheduleDAGSDNodes::RegDefIter::InitNodeNumDefs() {
+  // Check for phys reg copy.
+  if (!Node)
+    return;
+
+  if (!Node->isMachineOpcode()) {
+    if (Node->getOpcode() == ISD::CopyFromReg)
+      NodeNumDefs = 1;
+    else
+      NodeNumDefs = 0;
+    return;
+  }
+  unsigned POpc = Node->getMachineOpcode();
+  if (POpc == TargetOpcode::IMPLICIT_DEF) {
+    // No register need be allocated for this.
+    NodeNumDefs = 0;
+    return;
+  }
+  if (POpc == TargetOpcode::PATCHPOINT &&
+      Node->getValueType(0) == MVT::Other) {
+    // PATCHPOINT is defined to have one result, but it might really have none
+    // if we're not using CallingConv::AnyReg. Don't mistake the chain for a
+    // real definition.
+    NodeNumDefs = 0;
+    return;
+  }
+  unsigned NRegDefs = SchedDAG->TII->get(Node->getMachineOpcode()).getNumDefs();
+  // Some instructions define regs that are not represented in the selection DAG
+  // (e.g. unused flags). See tMOVi8. Make sure we don't access past NumValues.
+  NodeNumDefs = std::min(Node->getNumValues(), NRegDefs);
+  DefIdx = 0;
+}
+
+// Construct a RegDefIter for this SUnit and find the first valid value.
+ScheduleDAGSDNodes::RegDefIter::RegDefIter(const SUnit *SU,
+                                           const ScheduleDAGSDNodes *SD)
+  : SchedDAG(SD), Node(SU->getNode()), DefIdx(0), NodeNumDefs(0) {
+  InitNodeNumDefs();
+  Advance();
+}
+
+// Advance to the next valid value defined by the SUnit.
+void ScheduleDAGSDNodes::RegDefIter::Advance() {
+  for (;Node;) { // Visit all glued nodes.
+    for (;DefIdx < NodeNumDefs; ++DefIdx) {
+      if (!Node->hasAnyUseOfValue(DefIdx))
+        continue;
+      ValueType = Node->getSimpleValueType(DefIdx);
+      ++DefIdx;
+      return; // Found a normal regdef.
+    }
+    Node = Node->getGluedNode();
+    if (!Node) {
+      return; // No values left to visit.
+    }
+    InitNodeNumDefs();
+  }
+}
+
+void ScheduleDAGSDNodes::InitNumRegDefsLeft(SUnit *SU) {
+  assert(SU->NumRegDefsLeft == 0 && "expect a new node");
+  for (RegDefIter I(SU, this); I.IsValid(); I.Advance()) {
+    assert(SU->NumRegDefsLeft < USHRT_MAX && "overflow is ok but unexpected");
+    ++SU->NumRegDefsLeft;
+  }
+}
+
+void ScheduleDAGSDNodes::computeLatency(SUnit *SU) {
+  SDNode *N = SU->getNode();
+
+  // TokenFactor operands are considered zero latency, and some schedulers
+  // (e.g. Top-Down list) may rely on the fact that operand latency is nonzero
+  // whenever node latency is nonzero.
+  if (N && N->getOpcode() == ISD::TokenFactor) {
+    SU->Latency = 0;
+    return;
+  }
+
+  // Check to see if the scheduler cares about latencies.
+  if (forceUnitLatencies()) {
+    SU->Latency = 1;
+    return;
+  }
+
+  if (!InstrItins || InstrItins->isEmpty()) {
+    if (N && N->isMachineOpcode() &&
+        TII->isHighLatencyDef(N->getMachineOpcode()))
+      SU->Latency = HighLatencyCycles;
+    else
+      SU->Latency = 1;
+    return;
+  }
+
+  // Compute the latency for the node.  We use the sum of the latencies for
+  // all nodes glued together into this SUnit.
+  SU->Latency = 0;
+  for (SDNode *N = SU->getNode(); N; N = N->getGluedNode())
+    if (N->isMachineOpcode())
+      SU->Latency += TII->getInstrLatency(InstrItins, N);
+}
+
+void ScheduleDAGSDNodes::computeOperandLatency(SDNode *Def, SDNode *Use,
+                                               unsigned OpIdx, SDep& dep) const{
+  // Check to see if the scheduler cares about latencies.
+  if (forceUnitLatencies())
+    return;
+
+  if (dep.getKind() != SDep::Data)
+    return;
+
+  unsigned DefIdx = Use->getOperand(OpIdx).getResNo();
+  if (Use->isMachineOpcode())
+    // Adjust the use operand index by num of defs.
+    OpIdx += TII->get(Use->getMachineOpcode()).getNumDefs();
+  int Latency = TII->getOperandLatency(InstrItins, Def, DefIdx, Use, OpIdx);
+  if (Latency > 1 && Use->getOpcode() == ISD::CopyToReg &&
+      !BB->succ_empty()) {
+    unsigned Reg = cast<RegisterSDNode>(Use->getOperand(1))->getReg();
+    if (TargetRegisterInfo::isVirtualRegister(Reg))
+      // This copy is a liveout value. It is likely coalesced, so reduce the
+      // latency so not to penalize the def.
+      // FIXME: need target specific adjustment here?
+      Latency = (Latency > 1) ? Latency - 1 : 1;
+  }
+  if (Latency >= 0)
+    dep.setLatency(Latency);
+}
+
+void ScheduleDAGSDNodes::dumpNode(const SUnit &SU) const {
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+  dumpNodeName(SU);
+  dbgs() << ": ";
+
+  if (!SU.getNode()) {
+    dbgs() << "PHYS REG COPY\n";
+    return;
+  }
+
+  SU.getNode()->dump(DAG);
+  dbgs() << "\n";
+  SmallVector<SDNode *, 4> GluedNodes;
+  for (SDNode *N = SU.getNode()->getGluedNode(); N; N = N->getGluedNode())
+    GluedNodes.push_back(N);
+  while (!GluedNodes.empty()) {
+    dbgs() << "    ";
+    GluedNodes.back()->dump(DAG);
+    dbgs() << "\n";
+    GluedNodes.pop_back();
+  }
+#endif
+}
+
+void ScheduleDAGSDNodes::dump() const {
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+  if (EntrySU.getNode() != nullptr)
+    dumpNodeAll(EntrySU);
+  for (const SUnit &SU : SUnits)
+    dumpNodeAll(SU);
+  if (ExitSU.getNode() != nullptr)
+    dumpNodeAll(ExitSU);
+#endif
+}
+
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+void ScheduleDAGSDNodes::dumpSchedule() const {
+  for (unsigned i = 0, e = Sequence.size(); i != e; i++) {
+    if (SUnit *SU = Sequence[i])
+      dumpNode(*SU);
+    else
+      dbgs() << "**** NOOP ****\n";
+  }
+}
+#endif
+
+#ifndef NDEBUG
+/// VerifyScheduledSequence - Verify that all SUnits were scheduled and that
+/// their state is consistent with the nodes listed in Sequence.
+///
+void ScheduleDAGSDNodes::VerifyScheduledSequence(bool isBottomUp) {
+  unsigned ScheduledNodes = ScheduleDAG::VerifyScheduledDAG(isBottomUp);
+  unsigned Noops = 0;
+  for (unsigned i = 0, e = Sequence.size(); i != e; ++i)
+    if (!Sequence[i])
+      ++Noops;
+  assert(Sequence.size() - Noops == ScheduledNodes &&
+         "The number of nodes scheduled doesn't match the expected number!");
+}
+#endif // NDEBUG
+
+/// ProcessSDDbgValues - Process SDDbgValues associated with this node.
+static void
+ProcessSDDbgValues(SDNode *N, SelectionDAG *DAG, InstrEmitter &Emitter,
+                   SmallVectorImpl<std::pair<unsigned, MachineInstr*> > &Orders,
+                   DenseMap<SDValue, unsigned> &VRBaseMap, unsigned Order) {
+  if (!N->getHasDebugValue())
+    return;
+
+  // Opportunistically insert immediate dbg_value uses, i.e. those with the same
+  // source order number as N.
+  MachineBasicBlock *BB = Emitter.getBlock();
+  MachineBasicBlock::iterator InsertPos = Emitter.getInsertPos();
+  for (auto DV : DAG->GetDbgValues(N)) {
+    if (DV->isEmitted())
+      continue;
+    unsigned DVOrder = DV->getOrder();
+    if (!Order || DVOrder == Order) {
+      MachineInstr *DbgMI = Emitter.EmitDbgValue(DV, VRBaseMap);
+      if (DbgMI) {
+        Orders.push_back({DVOrder, DbgMI});
+        BB->insert(InsertPos, DbgMI);
+      }
+    }
+  }
+}
+
+// ProcessSourceNode - Process nodes with source order numbers. These are added
+// to a vector which EmitSchedule uses to determine how to insert dbg_value
+// instructions in the right order.
+static void
+ProcessSourceNode(SDNode *N, SelectionDAG *DAG, InstrEmitter &Emitter,
+                  DenseMap<SDValue, unsigned> &VRBaseMap,
+                  SmallVectorImpl<std::pair<unsigned, MachineInstr *>> &Orders,
+                  SmallSet<unsigned, 8> &Seen, MachineInstr *NewInsn) {
+  unsigned Order = N->getIROrder();
+  if (!Order || Seen.count(Order)) {
+    // Process any valid SDDbgValues even if node does not have any order
+    // assigned.
+    ProcessSDDbgValues(N, DAG, Emitter, Orders, VRBaseMap, 0);
+    return;
+  }
+
+  // If a new instruction was generated for this Order number, record it.
+  // Otherwise, leave this order number unseen: we will either find later
+  // instructions for it, or leave it unseen if there were no instructions at
+  // all.
+  if (NewInsn) {
+    Seen.insert(Order);
+    Orders.push_back({Order, NewInsn});
+  }
+
+  // Even if no instruction was generated, a Value may have become defined via
+  // earlier nodes. Try to process them now.
+  ProcessSDDbgValues(N, DAG, Emitter, Orders, VRBaseMap, Order);
+}
+
+void ScheduleDAGSDNodes::
+EmitPhysRegCopy(SUnit *SU, DenseMap<SUnit*, unsigned> &VRBaseMap,
+                MachineBasicBlock::iterator InsertPos) {
+  for (SUnit::const_pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
+       I != E; ++I) {
+    if (I->isCtrl()) continue;  // ignore chain preds
+    if (I->getSUnit()->CopyDstRC) {
+      // Copy to physical register.
+      DenseMap<SUnit*, unsigned>::iterator VRI = VRBaseMap.find(I->getSUnit());
+      assert(VRI != VRBaseMap.end() && "Node emitted out of order - late");
+      // Find the destination physical register.
+      unsigned Reg = 0;
+      for (SUnit::const_succ_iterator II = SU->Succs.begin(),
+             EE = SU->Succs.end(); II != EE; ++II) {
+        if (II->isCtrl()) continue;  // ignore chain preds
+        if (II->getReg()) {
+          Reg = II->getReg();
+          break;
+        }
+      }
+      BuildMI(*BB, InsertPos, DebugLoc(), TII->get(TargetOpcode::COPY), Reg)
+        .addReg(VRI->second);
+    } else {
+      // Copy from physical register.
+      assert(I->getReg() && "Unknown physical register!");
+      unsigned VRBase = MRI.createVirtualRegister(SU->CopyDstRC);
+      bool isNew = VRBaseMap.insert(std::make_pair(SU, VRBase)).second;
+      (void)isNew; // Silence compiler warning.
+      assert(isNew && "Node emitted out of order - early");
+      BuildMI(*BB, InsertPos, DebugLoc(), TII->get(TargetOpcode::COPY), VRBase)
+        .addReg(I->getReg());
+    }
+    break;
+  }
+}
+
+/// EmitSchedule - Emit the machine code in scheduled order. Return the new
+/// InsertPos and MachineBasicBlock that contains this insertion
+/// point. ScheduleDAGSDNodes holds a BB pointer for convenience, but this does
+/// not necessarily refer to returned BB. The emitter may split blocks.
+MachineBasicBlock *ScheduleDAGSDNodes::
+EmitSchedule(MachineBasicBlock::iterator &InsertPos) {
+  InstrEmitter Emitter(BB, InsertPos);
+  DenseMap<SDValue, unsigned> VRBaseMap;
+  DenseMap<SUnit*, unsigned> CopyVRBaseMap;
+  SmallVector<std::pair<unsigned, MachineInstr*>, 32> Orders;
+  SmallSet<unsigned, 8> Seen;
+  bool HasDbg = DAG->hasDebugValues();
+
+  // Emit a node, and determine where its first instruction is for debuginfo.
+  // Zero, one, or multiple instructions can be created when emitting a node.
+  auto EmitNode =
+      [&](SDNode *Node, bool IsClone, bool IsCloned,
+          DenseMap<SDValue, unsigned> &VRBaseMap) -> MachineInstr * {
+    // Fetch instruction prior to this, or end() if nonexistant.
+    auto GetPrevInsn = [&](MachineBasicBlock::iterator I) {
+      if (I == BB->begin())
+        return BB->end();
+      else
+        return std::prev(Emitter.getInsertPos());
+    };
+
+    MachineBasicBlock::iterator Before = GetPrevInsn(Emitter.getInsertPos());
+    Emitter.EmitNode(Node, IsClone, IsCloned, VRBaseMap);
+    MachineBasicBlock::iterator After = GetPrevInsn(Emitter.getInsertPos());
+
+    // If the iterator did not change, no instructions were inserted.
+    if (Before == After)
+      return nullptr;
+
+    MachineInstr *MI;
+    if (Before == BB->end()) {
+      // There were no prior instructions; the new ones must start at the
+      // beginning of the block.
+      MI = &Emitter.getBlock()->instr_front();
+    } else {
+      // Return first instruction after the pre-existing instructions.
+      MI = &*std::next(Before);
+    }
+
+    if (MI->isCall() && DAG->getTarget().Options.EnableDebugEntryValues)
+      MF.addCallArgsForwardingRegs(MI, DAG->getSDCallSiteInfo(Node));
+
+    return MI;
+  };
+
+  // If this is the first BB, emit byval parameter dbg_value's.
+  if (HasDbg && BB->getParent()->begin() == MachineFunction::iterator(BB)) {
+    SDDbgInfo::DbgIterator PDI = DAG->ByvalParmDbgBegin();
+    SDDbgInfo::DbgIterator PDE = DAG->ByvalParmDbgEnd();
+    for (; PDI != PDE; ++PDI) {
+      MachineInstr *DbgMI= Emitter.EmitDbgValue(*PDI, VRBaseMap);
+      if (DbgMI) {
+        BB->insert(InsertPos, DbgMI);
+        // We re-emit the dbg_value closer to its use, too, after instructions
+        // are emitted to the BB.
+        (*PDI)->clearIsEmitted();
+      }
+    }
+  }
+
+  for (unsigned i = 0, e = Sequence.size(); i != e; i++) {
+    SUnit *SU = Sequence[i];
+    if (!SU) {
+      // Null SUnit* is a noop.
+      TII->insertNoop(*Emitter.getBlock(), InsertPos);
+      continue;
+    }
+
+    // For pre-regalloc scheduling, create instructions corresponding to the
+    // SDNode and any glued SDNodes and append them to the block.
+    if (!SU->getNode()) {
+      // Emit a copy.
+      EmitPhysRegCopy(SU, CopyVRBaseMap, InsertPos);
+      continue;
+    }
+
+    SmallVector<SDNode *, 4> GluedNodes;
+    for (SDNode *N = SU->getNode()->getGluedNode(); N; N = N->getGluedNode())
+      GluedNodes.push_back(N);
+    while (!GluedNodes.empty()) {
+      SDNode *N = GluedNodes.back();
+      auto NewInsn = EmitNode(N, SU->OrigNode != SU, SU->isCloned, VRBaseMap);
+      // Remember the source order of the inserted instruction.
+      if (HasDbg)
+        ProcessSourceNode(N, DAG, Emitter, VRBaseMap, Orders, Seen, NewInsn);
+
+      if (MDNode *MD = DAG->getHeapAllocSite(N)) {
+        if (NewInsn && NewInsn->isCall())
+          MF.addCodeViewHeapAllocSite(NewInsn, MD);
+      }
+
+      GluedNodes.pop_back();
+    }
+    auto NewInsn =
+        EmitNode(SU->getNode(), SU->OrigNode != SU, SU->isCloned, VRBaseMap);
+    // Remember the source order of the inserted instruction.
+    if (HasDbg)
+      ProcessSourceNode(SU->getNode(), DAG, Emitter, VRBaseMap, Orders, Seen,
+                        NewInsn);
+    if (MDNode *MD = DAG->getHeapAllocSite(SU->getNode())) {
+      if (NewInsn && NewInsn->isCall())
+        MF.addCodeViewHeapAllocSite(NewInsn, MD);
+    }
+  }
+
+  // Insert all the dbg_values which have not already been inserted in source
+  // order sequence.
+  if (HasDbg) {
+    MachineBasicBlock::iterator BBBegin = BB->getFirstNonPHI();
+
+    // Sort the source order instructions and use the order to insert debug
+    // values. Use stable_sort so that DBG_VALUEs are inserted in the same order
+    // regardless of the host's implementation fo std::sort.
+    llvm::stable_sort(Orders, less_first());
+    std::stable_sort(DAG->DbgBegin(), DAG->DbgEnd(),
+                     [](const SDDbgValue *LHS, const SDDbgValue *RHS) {
+                       return LHS->getOrder() < RHS->getOrder();
+                     });
+
+    SDDbgInfo::DbgIterator DI = DAG->DbgBegin();
+    SDDbgInfo::DbgIterator DE = DAG->DbgEnd();
+    // Now emit the rest according to source order.
+    unsigned LastOrder = 0;
+    for (unsigned i = 0, e = Orders.size(); i != e && DI != DE; ++i) {
+      unsigned Order = Orders[i].first;
+      MachineInstr *MI = Orders[i].second;
+      // Insert all SDDbgValue's whose order(s) are before "Order".
+      assert(MI);
+      for (; DI != DE; ++DI) {
+        if ((*DI)->getOrder() < LastOrder || (*DI)->getOrder() >= Order)
+          break;
+        if ((*DI)->isEmitted())
+          continue;
+
+        MachineInstr *DbgMI = Emitter.EmitDbgValue(*DI, VRBaseMap);
+        if (DbgMI) {
+          if (!LastOrder)
+            // Insert to start of the BB (after PHIs).
+            BB->insert(BBBegin, DbgMI);
+          else {
+            // Insert at the instruction, which may be in a different
+            // block, if the block was split by a custom inserter.
+            MachineBasicBlock::iterator Pos = MI;
+            MI->getParent()->insert(Pos, DbgMI);
+          }
+        }
+      }
+      LastOrder = Order;
+    }
+    // Add trailing DbgValue's before the terminator. FIXME: May want to add
+    // some of them before one or more conditional branches?
+    SmallVector<MachineInstr*, 8> DbgMIs;
+    for (; DI != DE; ++DI) {
+      if ((*DI)->isEmitted())
+        continue;
+      assert((*DI)->getOrder() >= LastOrder &&
+             "emitting DBG_VALUE out of order");
+      if (MachineInstr *DbgMI = Emitter.EmitDbgValue(*DI, VRBaseMap))
+        DbgMIs.push_back(DbgMI);
+    }
+
+    MachineBasicBlock *InsertBB = Emitter.getBlock();
+    MachineBasicBlock::iterator Pos = InsertBB->getFirstTerminator();
+    InsertBB->insert(Pos, DbgMIs.begin(), DbgMIs.end());
+
+    SDDbgInfo::DbgLabelIterator DLI = DAG->DbgLabelBegin();
+    SDDbgInfo::DbgLabelIterator DLE = DAG->DbgLabelEnd();
+    // Now emit the rest according to source order.
+    LastOrder = 0;
+    for (const auto &InstrOrder : Orders) {
+      unsigned Order = InstrOrder.first;
+      MachineInstr *MI = InstrOrder.second;
+      if (!MI)
+        continue;
+
+      // Insert all SDDbgLabel's whose order(s) are before "Order".
+      for (; DLI != DLE &&
+             (*DLI)->getOrder() >= LastOrder && (*DLI)->getOrder() < Order;
+             ++DLI) {
+        MachineInstr *DbgMI = Emitter.EmitDbgLabel(*DLI);
+        if (DbgMI) {
+          if (!LastOrder)
+            // Insert to start of the BB (after PHIs).
+            BB->insert(BBBegin, DbgMI);
+          else {
+            // Insert at the instruction, which may be in a different
+            // block, if the block was split by a custom inserter.
+            MachineBasicBlock::iterator Pos = MI;
+            MI->getParent()->insert(Pos, DbgMI);
+          }
+        }
+      }
+      if (DLI == DLE)
+        break;
+
+      LastOrder = Order;
+    }
+  }
+
+  InsertPos = Emitter.getInsertPos();
+  return Emitter.getBlock();
+}
+
+/// Return the basic block label.
+std::string ScheduleDAGSDNodes::getDAGName() const {
+  return "sunit-dag." + BB->getFullName();
+}