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diff --git a/include/llvm/CodeGen/ScheduleDFS.h b/include/llvm/CodeGen/ScheduleDFS.h
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+//===- ScheduleDAGILP.h - ILP metric for ScheduleDAGInstrs ------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Definition of an ILP metric for machine level instruction scheduling.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CODEGEN_SCHEDULEDAGILP_H
+#define LLVM_CODEGEN_SCHEDULEDAGILP_H
+
+#include "llvm/CodeGen/ScheduleDAG.h"
+#include "llvm/Support/DataTypes.h"
+#include <vector>
+
+namespace llvm {
+
+class raw_ostream;
+class IntEqClasses;
+class ScheduleDAGInstrs;
+class SUnit;
+
+/// \brief Represent the ILP of the subDAG rooted at a DAG node.
+///
+/// When computed using bottom-up DFS, this metric assumes that the DAG is a
+/// forest of trees with roots at the bottom of the schedule branching upward.
+struct ILPValue {
+  unsigned InstrCount;
+  /// Length may either correspond to depth or height, depending on direction,
+  /// and cycles or nodes depending on context.
+  unsigned Length;
+
+  ILPValue(unsigned count, unsigned length):
+    InstrCount(count), Length(length) {}
+
+  // Order by the ILP metric's value.
+  bool operator<(ILPValue RHS) const {
+    return (uint64_t)InstrCount * RHS.Length
+      < (uint64_t)Length * RHS.InstrCount;
+  }
+  bool operator>(ILPValue RHS) const {
+    return RHS < *this;
+  }
+  bool operator<=(ILPValue RHS) const {
+    return (uint64_t)InstrCount * RHS.Length
+      <= (uint64_t)Length * RHS.InstrCount;
+  }
+  bool operator>=(ILPValue RHS) const {
+    return RHS <= *this;
+  }
+
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+  void print(raw_ostream &OS) const;
+
+  void dump() const;
+#endif
+};
+
+/// \brief Compute the values of each DAG node for various metrics during DFS.
+///
+/// ILPValues summarize the DAG subtree rooted at each node up to
+/// SubtreeLimit. ILPValues are also valid for interior nodes of a subtree, not
+/// just the root.
+class SchedDFSResult {
+  friend class SchedDFSImpl;
+
+  /// \brief Per-SUnit data computed during DFS for various metrics.
+  struct NodeData {
+    unsigned InstrCount;
+    unsigned SubtreeID;
+
+    NodeData(): InstrCount(0), SubtreeID(0) {}
+  };
+
+  /// \brief Record a connection between subtrees and the connection level.
+  struct Connection {
+    unsigned TreeID;
+    unsigned Level;
+
+    Connection(unsigned tree, unsigned level): TreeID(tree), Level(level) {}
+  };
+
+  bool IsBottomUp;
+  unsigned SubtreeLimit;
+  /// DFS results for each SUnit in this DAG.
+  std::vector<NodeData> DFSData;
+
+  // For each subtree discovered during DFS, record its connections to other
+  // subtrees.
+  std::vector<SmallVector<Connection, 4> > SubtreeConnections;
+
+  /// Cache the current connection level of each subtree.
+  /// This mutable array is updated during scheduling.
+  std::vector<unsigned> SubtreeConnectLevels;
+
+public:
+  SchedDFSResult(bool IsBU, unsigned lim)
+    : IsBottomUp(IsBU), SubtreeLimit(lim) {}
+
+  /// \brief Clear the results.
+  void clear() {
+    DFSData.clear();
+    SubtreeConnections.clear();
+    SubtreeConnectLevels.clear();
+  }
+
+  /// \brief Initialize the result data with the size of the DAG.
+  void resize(unsigned NumSUnits) {
+    DFSData.resize(NumSUnits);
+  }
+
+  /// \brief Compute various metrics for the DAG with given roots.
+  void compute(ArrayRef<SUnit *> Roots);
+
+  /// \brief Get the ILP value for a DAG node.
+  ///
+  /// A leaf node has an ILP of 1/1.
+  ILPValue getILP(const SUnit *SU) {
+    return ILPValue(DFSData[SU->NodeNum].InstrCount, 1 + SU->getDepth());
+  }
+
+  /// \brief The number of subtrees detected in this DAG.
+  unsigned getNumSubtrees() const { return SubtreeConnectLevels.size(); }
+
+  /// \brief Get the ID of the subtree the given DAG node belongs to.
+  unsigned getSubtreeID(const SUnit *SU) {
+    return DFSData[SU->NodeNum].SubtreeID;
+  }
+
+  /// \brief Get the connection level of a subtree.
+  ///
+  /// For bottom-up trees, the connection level is the latency depth (in cycles)
+  /// of the deepest connection to another subtree.
+  unsigned getSubtreeLevel(unsigned SubtreeID) {
+    return SubtreeConnectLevels[SubtreeID];
+  }
+
+  /// \brief Scheduler callback to update SubtreeConnectLevels when a tree is
+  /// initially scheduled.
+  void scheduleTree(unsigned SubtreeID);
+};
+
+raw_ostream &operator<<(raw_ostream &OS, const ILPValue &Val);
+
+} // namespace llvm
+
+#endif