/* Copyright 2018 The TensorFlow Authors. All Rights Reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
==============================================================================*/

#include "tensorflow/compiler/jit/partially_decluster_pass.h"

#include "absl/memory/memory.h"
#include "tensorflow/cc/framework/ops.h"
#include "tensorflow/cc/ops/array_ops.h"
#include "tensorflow/cc/ops/control_flow_ops_internal.h"
#include "tensorflow/cc/ops/function_ops.h"
#include "tensorflow/cc/ops/sendrecv_ops.h"
#include "tensorflow/cc/ops/standard_ops.h"
#include "tensorflow/compiler/jit/defs.h"
#include "tensorflow/compiler/jit/xla_cluster_util.h"
#include "tensorflow/compiler/tf2xla/cc/ops/xla_ops.h"
#include "tensorflow/compiler/tf2xla/xla_op_kernel.h"
#include "tensorflow/compiler/tf2xla/xla_op_registry.h"
#include "tensorflow/core/framework/function.h"
#include "tensorflow/core/framework/function.pb.h"
#include "tensorflow/core/framework/node_def_util.h"
#include "tensorflow/core/framework/op.h"
#include "tensorflow/core/graph/algorithm.h"
#include "tensorflow/core/graph/graph_constructor.h"
#include "tensorflow/core/graph/graph_def_builder.h"
#include "tensorflow/core/graph/graph_def_builder_util.h"
#include "tensorflow/core/lib/core/status_test_util.h"
#include "tensorflow/core/platform/test.h"

namespace tensorflow {
namespace {
REGISTER_OP("FakeNullary").Output("out: int32");

REGISTER_OP("FakeBinary")
    .Input("host_in: int32")
    .Input("device_in: int32")
    .Output("host_out: int32")
    .Output("device_out: int32");

REGISTER_OP("FakeResourceVar").Output("out: resource");

REGISTER_OP("FakeResourceUpdate")
    .Input("in: resource")
    .Output("out: resource")
    .Output("something_else: int32");

class FakeBinaryOp : public OpKernel {
 public:
  explicit FakeBinaryOp(OpKernelConstruction* context) : OpKernel(context) {}

  void Compute(OpKernelContext* ctx) override { CHECK(false); }
};

class FakeResourceUpdateOp : public OpKernel {
 public:
  explicit FakeResourceUpdateOp(OpKernelConstruction* context)
      : OpKernel(context) {}

  void Compute(OpKernelContext* ctx) override { CHECK(false); }
};

REGISTER_KERNEL_BUILDER(Name("FakeBinary")
                            .Device(DEVICE_CPU)
                            .HostMemory("host_in")
                            .HostMemory("host_out"),
                        FakeBinaryOp);

REGISTER_KERNEL_BUILDER(
    Name("FakeResourceUpdate").Device(DEVICE_CPU).HostMemory("something_else"),
    FakeResourceUpdateOp);

Status PartiallyDecluster(std::unique_ptr<Graph>* graph) {
  FixupSourceAndSinkEdges(graph->get());
  // Assign all nodes to the CPU device.
  static const char* kCpuDevice = "/job:localhost/replica:0/task:0/cpu:0";
  for (Node* n : (*graph)->nodes()) {
    if (n->assigned_device_name().empty()) {
      n->set_assigned_device_name(kCpuDevice);
    }
  }

  GraphOptimizationPassOptions opt_options;
  opt_options.graph = graph;
  FunctionDefLibrary fdef_lib;
  FunctionLibraryDefinition flib_def(OpRegistry::Global(), fdef_lib);
  opt_options.flib_def = &flib_def;
  SessionOptions session_options;
  session_options.env = Env::Default();
  opt_options.session_options = &session_options;
  PartiallyDeclusterPass pass;
  return pass.Run(opt_options);
}

Node* FindNodeByName(const Graph& graph, const string& name) {
  for (Node* node : graph.nodes()) {
    if (node->name() == name) {
      return node;
    }
  }
  return nullptr;
}

bool GetInputsForNode(const Graph& graph, const string& node_name,
                      std::vector<Node*>* inputs) {
  const Node* node = FindNodeByName(graph, node_name);
  if (node == nullptr) {
    return false;
  }
  for (const Edge* e : node->in_edges()) {
    inputs->push_back(e->src());
  }
  std::sort(inputs->begin(), inputs->end(), NodeComparatorName());
  return true;
}

TEST(PartiallyDeclusterPassTest, ClusteredAndUnclustered) {
  std::unique_ptr<Graph> graph(new Graph(OpRegistry::Global()));
  {
    GraphDefBuilder builder(GraphDefBuilder::kFailImmediately);
    Node* input =
        ops::SourceOp("FakeNullary", builder.opts().WithName("Input"));
    Node* clustered_producer =
        ops::BinaryOp("FakeBinary", input, input,
                      builder.opts().WithName("ClusteredProducer"));
    ops::BinaryOp("FakeBinary", clustered_producer, input,
                  builder.opts().WithName("UnclusteredConsumer"));
    Node* clustered_consumer =
        ops::BinaryOp("FakeBinary", {clustered_producer, 1}, input,
                      builder.opts().WithName("ClusteredConsumer"));
    clustered_producer->AddAttr(kXlaClusterAttr, "cluster_0");
    clustered_consumer->AddAttr(kXlaClusterAttr, "cluster_0");
    TF_EXPECT_OK(GraphDefBuilderToGraph(builder, graph.get()));
  }

  TF_ASSERT_OK(PartiallyDecluster(&graph));
  std::vector<Node*> unclustered_consumer_inputs;
  ASSERT_TRUE(GetInputsForNode(*graph, "UnclusteredConsumer",
                               &unclustered_consumer_inputs));
  ASSERT_EQ(unclustered_consumer_inputs.size(), 2);
  EXPECT_EQ(unclustered_consumer_inputs[0]->name(),
            "ClusteredProducer/declustered");
  EXPECT_EQ(unclustered_consumer_inputs[1]->name(), "Input");

  std::vector<Node*> clustered_consumer_inputs;
  ASSERT_TRUE(GetInputsForNode(*graph, "ClusteredConsumer",
                               &clustered_consumer_inputs));
  ASSERT_EQ(clustered_consumer_inputs.size(), 2);
  EXPECT_EQ(clustered_consumer_inputs[0]->name(), "ClusteredProducer");
  EXPECT_EQ(clustered_consumer_inputs[1]->name(), "Input");
}

TEST(PartiallyDeclusterPassTest, DifferentClusters) {
  std::unique_ptr<Graph> graph(new Graph(OpRegistry::Global()));
  {
    GraphDefBuilder builder(GraphDefBuilder::kFailImmediately);
    Node* input =
        ops::SourceOp("FakeNullary", builder.opts().WithName("Input"));
    Node* clustered_producer =
        ops::BinaryOp("FakeBinary", input, input,
                      builder.opts().WithName("ClusteredProducer"));
    Node* consumer_in_different_cluster =
        ops::BinaryOp("FakeBinary", clustered_producer, input,
                      builder.opts().WithName("ConsumerInDifferentCluster"));
    Node* clustered_consumer =
        ops::BinaryOp("FakeBinary", input, {clustered_producer, 1},
                      builder.opts().WithName("ClusteredConsumer"));
    clustered_producer->AddAttr(kXlaClusterAttr, "cluster_0");
    clustered_consumer->AddAttr(kXlaClusterAttr, "cluster_0");
    consumer_in_different_cluster->AddAttr(kXlaClusterAttr, "cluster_1");
    TF_EXPECT_OK(GraphDefBuilderToGraph(builder, graph.get()));
  }

  TF_ASSERT_OK(PartiallyDecluster(&graph));
  std::vector<Node*> inputs;
  ASSERT_TRUE(GetInputsForNode(*graph, "ConsumerInDifferentCluster", &inputs));
  ASSERT_EQ(inputs.size(), 2);
  EXPECT_EQ(inputs[0]->name(), "ClusteredProducer/declustered");
  EXPECT_EQ(inputs[1]->name(), "Input");
}

TEST(PartiallyDeclusterPassTest, DontDeclusterIfUserIsDeviceMem) {
  std::unique_ptr<Graph> graph(new Graph(OpRegistry::Global()));
  {
    GraphDefBuilder builder(GraphDefBuilder::kFailImmediately);
    Node* input =
        ops::SourceOp("FakeNullary", builder.opts().WithName("Input"));
    Node* clustered_producer =
        ops::BinaryOp("FakeBinary", input, input,
                      builder.opts().WithName("ClusteredProducer"));
    // The first input is hostmem and the second input is devicemem.
    Node* consumer_in_different_cluster =
        ops::BinaryOp("FakeBinary", input, clustered_producer,
                      builder.opts().WithName("ConsumerInDifferentCluster"));
    Node* clustered_consumer =
        ops::BinaryOp("FakeBinary", input, {clustered_producer, 1},
                      builder.opts().WithName("ClusteredConsumer"));
    clustered_producer->AddAttr(kXlaClusterAttr, "cluster_0");
    clustered_consumer->AddAttr(kXlaClusterAttr, "cluster_0");
    consumer_in_different_cluster->AddAttr(kXlaClusterAttr, "cluster_1");
    TF_EXPECT_OK(GraphDefBuilderToGraph(builder, graph.get()));
  }

  TF_ASSERT_OK(PartiallyDecluster(&graph));
  std::vector<Node*> inputs;
  ASSERT_TRUE(GetInputsForNode(*graph, "ConsumerInDifferentCluster", &inputs));
  ASSERT_EQ(inputs.size(), 2);
  EXPECT_EQ(inputs[0]->name(), "ClusteredProducer");
  EXPECT_EQ(inputs[1]->name(), "Input");
}

TEST(PartiallyDeclusterPassTest, DontDuplicateResourceVarOps) {
  std::unique_ptr<Graph> graph(new Graph(OpRegistry::Global()));
  {
    GraphDefBuilder builder(GraphDefBuilder::kFailImmediately);
    Node* input =
        ops::SourceOp("FakeNullary", builder.opts().WithName("Input"));
    Node* resource_var = ops::SourceOp("FakeResourceVar",
                                       builder.opts().WithName("ResourceVar"));
    Node* clustered_producer =
        ops::UnaryOp("FakeResourceUpdate", resource_var,
                     builder.opts().WithName("ClusteredProducer"));
    Node* consumer_in_different_cluster =
        ops::BinaryOp("FakeBinary", {clustered_producer, 1}, input,
                      builder.opts().WithName("ConsumerInDifferentCluster"));
    Node* clustered_consumer =
        ops::BinaryOp("FakeBinary", input, {clustered_producer, 1},
                      builder.opts().WithName("ClusteredConsumer"));
    clustered_producer->AddAttr(kXlaClusterAttr, "cluster_0");
    clustered_consumer->AddAttr(kXlaClusterAttr, "cluster_0");
    consumer_in_different_cluster->AddAttr(kXlaClusterAttr, "cluster_1");
    TF_EXPECT_OK(GraphDefBuilderToGraph(builder, graph.get()));
  }

  TF_ASSERT_OK(PartiallyDecluster(&graph));
  std::vector<Node*> inputs;
  ASSERT_TRUE(GetInputsForNode(*graph, "ConsumerInDifferentCluster", &inputs));
  ASSERT_EQ(inputs.size(), 2);
  EXPECT_EQ(inputs[0]->name(), "ClusteredProducer");
  EXPECT_EQ(inputs[1]->name(), "Input");
}

TEST(PartiallyDeclusterPassTest, DeclusterDependentNodes) {
  std::unique_ptr<Graph> graph(new Graph(OpRegistry::Global()));
  {
    GraphDefBuilder builder(GraphDefBuilder::kFailImmediately);
    Node* input =
        ops::SourceOp("FakeNullary", builder.opts().WithName("Input"));
    Node* clustered_producer_0 =
        ops::BinaryOp("FakeBinary", input, input,
                      builder.opts().WithName("ClusteredProducer0"));
    Node* clustered_producer_1 =
        ops::BinaryOp("FakeBinary", clustered_producer_0, input,
                      builder.opts().WithName("ClusteredProducer1"));
    ops::BinaryOp("FakeBinary", clustered_producer_1, input,
                  builder.opts().WithName("UnclusteredConsumer"));
    Node* clustered_consumer =
        ops::BinaryOp("FakeBinary", {clustered_producer_1, 1}, input,
                      builder.opts().WithName("ClusteredConsumer"));
    clustered_producer_0->AddAttr(kXlaClusterAttr, "cluster_0");
    clustered_producer_1->AddAttr(kXlaClusterAttr, "cluster_0");
    clustered_consumer->AddAttr(kXlaClusterAttr, "cluster_0");
    TF_EXPECT_OK(GraphDefBuilderToGraph(builder, graph.get()));
  }

  TF_ASSERT_OK(PartiallyDecluster(&graph));
  std::vector<Node*> unclustered_consumer_inputs, declustered_producer_1_inputs;

  ASSERT_TRUE(GetInputsForNode(*graph, "UnclusteredConsumer",
                               &unclustered_consumer_inputs));
  ASSERT_EQ(unclustered_consumer_inputs.size(), 2);
  EXPECT_EQ(unclustered_consumer_inputs[0]->name(),
            "ClusteredProducer1/declustered");
  EXPECT_EQ(unclustered_consumer_inputs[1]->name(), "Input");

  ASSERT_TRUE(GetInputsForNode(*graph, "ClusteredProducer1/declustered",
                               &declustered_producer_1_inputs));
  ASSERT_EQ(declustered_producer_1_inputs.size(), 2);
  EXPECT_EQ(declustered_producer_1_inputs[0]->name(),
            "ClusteredProducer0/declustered");
  EXPECT_EQ(declustered_producer_1_inputs[1]->name(), "Input");
}

void AddToCluster(absl::Span<Node* const> nodes,
                  absl::string_view cluster_name) {
  for (Node* n : nodes) {
    n->AddAttr(kXlaClusterAttr, string(cluster_name));
  }
}

TEST(PartiallyDeclusterPassTest, DeclusterMustBeConstantNodes) {
  tensorflow::Scope s = tensorflow::Scope::NewRootScope();
  Output shape_a = ops::Placeholder(s.WithOpName("shape_a"), DT_INT32,
                                    ops::Placeholder::Attrs{});
  Output shape_b = ops::Placeholder(s.WithOpName("shape_b"), DT_INT32,
                                    ops::Placeholder::Attrs{});
  Output shape = ops::Add(s.WithOpName("shape"), shape_a, shape_b);

  Output reshape_input = ops::Placeholder(s.WithOpName("reshape_input"),
                                          DT_FLOAT, ops::Placeholder::Attrs{});
  Output reshape = ops::Reshape(s.WithOpName("reshape"), reshape_input, shape);

  AddToCluster({shape.node(), reshape.node()}, "cluster_0");

  auto graph = absl::make_unique<Graph>(OpRegistry::Global());
  TF_ASSERT_OK(s.ToGraph(graph.get()));
  TF_ASSERT_OK(PartiallyDecluster(&graph));

  const Node* n = FindNodeByName(*graph, "shape");
  ASSERT_NE(n, nullptr);

  EXPECT_EQ(GetXlaClusterForNode(*n), absl::nullopt);
}

TEST(PartiallyDeclusterPassTest, DeclusteringStopsAtMetadataOps) {
  tensorflow::Scope s = tensorflow::Scope::NewRootScope();
  Output input_a = ops::Placeholder(s.WithOpName("input_a"), DT_INT32,
                                    ops::Placeholder::Attrs{});
  Output input_b = ops::Placeholder(s.WithOpName("shape_b"), DT_FLOAT,
                                    ops::Placeholder::Attrs{});
  Output mul = ops::Mul(s.WithOpName("mul"), input_b, input_b);
  Output shape_of_mul = ops::Shape(s.WithOpName("shape_of_mul"), mul);

  Output shape = ops::Add(s.WithOpName("shape"), shape_of_mul, input_a);

  Output reshape_input = ops::Placeholder(s.WithOpName("reshape_input"),
                                          DT_FLOAT, ops::Placeholder::Attrs{});
  Output reshape = ops::Reshape(s.WithOpName("reshape"), reshape_input, shape);

  AddToCluster({mul.node(), shape_of_mul.node(), shape.node(), reshape.node()},
               "cluster_0");

  std::unique_ptr<Graph> graph = absl::make_unique<Graph>(OpRegistry::Global());
  TF_ASSERT_OK(s.ToGraph(graph.get()));
  TF_ASSERT_OK(PartiallyDecluster(&graph));

  const Node* n = FindNodeByName(*graph, "shape");
  ASSERT_NE(n, nullptr);

  EXPECT_EQ(GetXlaClusterForNode(*n), "cluster_0");
}

TEST(PartiallyDeclusterPassTest, EdgeAcrossDifferentClusters) {
  tensorflow::Scope s = tensorflow::Scope::NewRootScope();
  Output shape_a = ops::Placeholder(s.WithOpName("shape_a"), DT_INT32,
                                    ops::Placeholder::Attrs{});
  Output shape_b = ops::Placeholder(s.WithOpName("shape_b"), DT_INT32,
                                    ops::Placeholder::Attrs{});
  Output shape = ops::Add(s.WithOpName("shape"), shape_a, shape_b);

  Output reshape_input = ops::Placeholder(s.WithOpName("reshape_input"),
                                          DT_FLOAT, ops::Placeholder::Attrs{});
  Output reshape = ops::Reshape(s.WithOpName("reshape"), reshape_input, shape);

  AddToCluster({reshape.node()}, "cluster_0");
  AddToCluster({shape.node()}, "cluster_1");

  std::unique_ptr<Graph> graph = absl::make_unique<Graph>(OpRegistry::Global());
  TF_ASSERT_OK(s.ToGraph(graph.get()));
  TF_ASSERT_OK(PartiallyDecluster(&graph));

  const Node* n = FindNodeByName(*graph, "shape");
  ASSERT_NE(n, nullptr);

  EXPECT_EQ(GetXlaClusterForNode(*n), "cluster_1");
}

TEST(PartiallyDeclusterPassTest, DontDeclusterXlaDeviceOps) {
  tensorflow::Scope s = tensorflow::Scope::NewRootScope();
  Output shape_a = ops::Placeholder(s.WithOpName("shape_a"), DT_INT32,
                                    ops::Placeholder::Attrs{});
  Output shape_b = ops::Placeholder(s.WithOpName("shape_b"), DT_INT32,
                                    ops::Placeholder::Attrs{});
  Output shape = ops::Add(s.WithOpName("shape"), shape_a, shape_b);

  Output reshape_input = ops::Placeholder(s.WithOpName("reshape_input"),
                                          DT_FLOAT, ops::Placeholder::Attrs{});
  Output reshape = ops::Reshape(s.WithOpName("reshape"), reshape_input, shape);

  AddToCluster({shape.node(), reshape.node()}, "cluster_0");

  std::unique_ptr<Graph> graph = absl::make_unique<Graph>(OpRegistry::Global());
  TF_ASSERT_OK(s.ToGraph(graph.get()));

  // This is needed to register the XLA_GPU device.
  std::vector<std::unique_ptr<Device>> devices;
  TF_ASSERT_OK(DeviceFactory::AddDevices(
      SessionOptions(), "/job:localhost/replica:0/task:0", &devices));

  // Scope::ToGraph loses the assigned device name since it goes through
  // GraphDef/NodeDef which does not have a field for the assigned device name.
  Node* n = FindNodeByName(*graph, "shape");
  ASSERT_NE(n, nullptr);
  n->set_assigned_device_name(
      "/job:localhost/replica:0/task:0/device:XLA_GPU:0");

  TF_ASSERT_OK(PartiallyDecluster(&graph));

  EXPECT_EQ(GetXlaClusterForNode(*n), "cluster_0");
}

TEST(PartiallyDeclusterPassTest, DontDeclusterNonTensorFlowOps) {
  tensorflow::Scope s = tensorflow::Scope::NewRootScope();
  Output dynamic_slice_operand =
      ops::Placeholder(s.WithOpName("dynamic_slice_operand"), DT_INT32,
                       ops::Placeholder::Attrs{});
  Output dynamic_slice_begin = ops::Placeholder(
      s.WithOpName("dynamic_slice_begin"), DT_INT32, ops::Placeholder::Attrs{});
  Output dynamic_slice_size = ops::Placeholder(
      s.WithOpName("dynamic_slice_size"), DT_INT32, ops::Placeholder::Attrs{});
  Output dynamic_slice =
      ops::XlaDynamicSlice(s.WithOpName("dynamic_slice"), dynamic_slice_operand,
                           dynamic_slice_begin, dynamic_slice_size);

  Output reshape_input = ops::Placeholder(s.WithOpName("reshape_input"),
                                          DT_FLOAT, ops::Placeholder::Attrs{});
  Output reshape =
      ops::Reshape(s.WithOpName("reshape"), reshape_input, dynamic_slice);

  AddToCluster({dynamic_slice.node(), reshape.node()}, "cluster_0");

  std::unique_ptr<Graph> graph = absl::make_unique<Graph>(OpRegistry::Global());
  TF_ASSERT_OK(s.ToGraph(graph.get()));

  Node* n = FindNodeByName(*graph, "dynamic_slice");
  ASSERT_NE(n, nullptr);

  TF_ASSERT_OK(PartiallyDecluster(&graph));

  EXPECT_EQ(GetXlaClusterForNode(*n), "cluster_0");
}

TEST(PartiallyDeclusterPassTest, EliminatedUnusedNodes) {
  const char* const kClusteredProducer0Name = "ClusteredProducer0";
  const char* const kClusteredProducer1Name = "ClusteredProducer1";

  std::unique_ptr<Graph> graph(new Graph(OpRegistry::Global()));
  {
    GraphDefBuilder builder(GraphDefBuilder::kFailImmediately);
    Node* input =
        ops::SourceOp("FakeNullary", builder.opts().WithName("Input"));
    Node* clustered_producer_0 =
        ops::BinaryOp("FakeBinary", input, input,
                      builder.opts().WithName(kClusteredProducer0Name));
    Node* clustered_producer_1 =
        ops::BinaryOp("FakeBinary", clustered_producer_0, input,
                      builder.opts().WithName(kClusteredProducer1Name));
    ops::BinaryOp("FakeBinary", clustered_producer_1, input,
                  builder.opts().WithName("UnclusteredConsumer"));
    clustered_producer_0->AddAttr(kXlaClusterAttr, "cluster_0");
    clustered_producer_1->AddAttr(kXlaClusterAttr, "cluster_0");
    TF_EXPECT_OK(GraphDefBuilderToGraph(builder, graph.get()));
  }

  TF_ASSERT_OK(PartiallyDecluster(&graph));
  EXPECT_EQ(FindNodeByName(*graph, kClusteredProducer0Name), nullptr);
  EXPECT_EQ(FindNodeByName(*graph, kClusteredProducer1Name), nullptr);
}

TEST(PartiallyDeclusterPassTest, MetadataOpsDontStartClusters) {
  tensorflow::Scope root = tensorflow::Scope::NewRootScope();
  tensorflow::Scope in_cluster_and = root.WithXlaCluster("cluster_0");

  Output a = ops::Placeholder(root.WithOpName("a"), DT_FLOAT);
  Output b = ops::Shape(in_cluster_and.WithOpName("b"), a);
  Output c = ops::Rank(in_cluster_and.WithOpName("c"), b);
  Output d = ops::Size(in_cluster_and.WithOpName("d"), c);
  (void)ops::Shape(in_cluster_and.WithOpName("e"), d);

  std::unique_ptr<Graph> graph = absl::make_unique<Graph>(OpRegistry::Global());
  TF_ASSERT_OK(root.ToGraph(graph.get()));

  TF_ASSERT_OK(PartiallyDecluster(&graph));

  Node* n_b = FindNodeByName(*graph, "b");
  ASSERT_NE(n_b, nullptr);
  EXPECT_EQ(GetXlaClusterForNode(*n_b), absl::nullopt);

  Node* n_c = FindNodeByName(*graph, "c");
  ASSERT_NE(n_c, nullptr);
  EXPECT_EQ(GetXlaClusterForNode(*n_c), absl::nullopt);

  Node* n_d = FindNodeByName(*graph, "d");
  ASSERT_NE(n_d, nullptr);
  EXPECT_EQ(GetXlaClusterForNode(*n_d), absl::nullopt);

  Node* n_e = FindNodeByName(*graph, "e");
  ASSERT_NE(n_e, nullptr);
  EXPECT_EQ(GetXlaClusterForNode(*n_e), absl::nullopt);
}

TEST(PartiallyDeclusterPassTest, MetaConsumersArentDeclustered) {
  tensorflow::Scope root = tensorflow::Scope::NewRootScope();
  tensorflow::Scope in_cluster_and = root.WithXlaCluster("cluster_0");
  std::unique_ptr<Graph> graph = absl::make_unique<Graph>(OpRegistry::Global());
  Output a = ops::Placeholder(root.WithOpName("a"), DT_FLOAT);
  Output b = ops::Add(in_cluster_and.WithOpName("b"), a, a);
  Output c = ops::Rank(in_cluster_and.WithOpName("c"), b);

  Output e;
  TF_ASSERT_OK(
      CreateOutputWithScope("FakeBinary", {c, c}, root.WithOpName("e"), &e));

  TF_ASSERT_OK(root.ToGraph(graph.get()));
  TF_ASSERT_OK(PartiallyDecluster(&graph));

  Node* n_b = FindNodeByName(*graph, "b");
  ASSERT_NE(n_b, nullptr);
  EXPECT_EQ(GetXlaClusterForNode(*n_b), "cluster_0");

  Node* n_c = FindNodeByName(*graph, "c");
  ASSERT_NE(n_c, nullptr);
  EXPECT_EQ(GetXlaClusterForNode(*n_c), "cluster_0");
}

}  // namespace
}  // namespace tensorflow
