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diff --git a/llvm/tools/llvm-exegesis/lib/Clustering.h b/llvm/tools/llvm-exegesis/lib/Clustering.h
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+//===-- Clustering.h --------------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// Utilities to compute benchmark result clusters.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TOOLS_LLVM_EXEGESIS_CLUSTERING_H
+#define LLVM_TOOLS_LLVM_EXEGESIS_CLUSTERING_H
+
+#include "BenchmarkResult.h"
+#include "llvm/Support/Error.h"
+#include <vector>
+
+namespace exegesis {
+
+class InstructionBenchmarkClustering {
+public:
+  // Clusters `Points` using DBSCAN with the given parameters. See the cc file
+  // for more explanations on the algorithm.
+  static llvm::Expected<InstructionBenchmarkClustering>
+  create(const std::vector<InstructionBenchmark> &Points, size_t MinPts,
+         double Epsilon);
+
+  class ClusterId {
+  public:
+    static ClusterId noise() { return ClusterId(kNoise); }
+    static ClusterId error() { return ClusterId(kError); }
+    static ClusterId makeValid(int Id) {
+      assert(Id >= 0);
+      return ClusterId(Id);
+    }
+    ClusterId() : Id_(kUndef) {}
+    bool operator==(const ClusterId &O) const { return Id_ == O.Id_; }
+
+    bool isValid() const { return Id_ >= 0; }
+    bool isUndef() const { return Id_ == kUndef; }
+    bool isNoise() const { return Id_ == kNoise; }
+    bool isError() const { return Id_ == kError; }
+
+    // Precondition: isValid().
+    size_t getId() const {
+      assert(isValid());
+      return static_cast<size_t>(Id_);
+    }
+
+  private:
+    explicit ClusterId(int Id) : Id_(Id) {}
+    static constexpr const int kUndef = -1;
+    static constexpr const int kNoise = -2;
+    static constexpr const int kError = -3;
+    int Id_;
+  };
+
+  struct Cluster {
+    Cluster() = delete;
+    explicit Cluster(const ClusterId &Id) : Id(Id) {}
+
+    const ClusterId Id;
+    // Indices of benchmarks within the cluster.
+    std::vector<int> PointIndices;
+  };
+
+  ClusterId getClusterIdForPoint(size_t P) const {
+    return ClusterIdForPoint_[P];
+  }
+
+  const Cluster &getCluster(ClusterId Id) const {
+    assert(!Id.isUndef() && "unlabeled cluster");
+    if (Id.isNoise()) {
+      return NoiseCluster_;
+    }
+    if (Id.isError()) {
+      return ErrorCluster_;
+    }
+    return Clusters_[Id.getId()];
+  }
+
+  const std::vector<Cluster> &getValidClusters() const { return Clusters_; }
+
+private:
+  InstructionBenchmarkClustering();
+  llvm::Error validateAndSetup(const std::vector<InstructionBenchmark> &Points);
+  void dbScan(const std::vector<InstructionBenchmark> &Points, size_t MinPts,
+              double EpsilonSquared);
+  int NumDimensions_ = 0;
+  // ClusterForPoint_[P] is the cluster id for Points[P].
+  std::vector<ClusterId> ClusterIdForPoint_;
+  std::vector<Cluster> Clusters_;
+  Cluster NoiseCluster_;
+  Cluster ErrorCluster_;
+};
+
+} // namespace exegesis
+
+#endif // LLVM_TOOLS_LLVM_EXEGESIS_CLUSTERING_H