/* Copyright 2017 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/xla/service/transpose_folding.h"

#include <memory>
#include <unordered_set>
#include <vector>

#include "tensorflow/compiler/xla/client/computation_builder.h"
#include "tensorflow/compiler/xla/literal_util.h"
#include "tensorflow/compiler/xla/service/gpu/ir_emission_utils.h"
#include "tensorflow/compiler/xla/service/hlo_computation.h"
#include "tensorflow/compiler/xla/service/hlo_instruction.h"
#include "tensorflow/compiler/xla/service/hlo_module.h"
#include "tensorflow/compiler/xla/service/hlo_opcode.h"
#include "tensorflow/compiler/xla/service/shape_inference.h"
#include "tensorflow/compiler/xla/shape_util.h"
#include "tensorflow/compiler/xla/test.h"
#include "tensorflow/compiler/xla/test_helpers.h"
#include "tensorflow/compiler/xla/tests/hlo_test_base.h"
#include "tensorflow/compiler/xla/xla_data.pb.h"
#include "tensorflow/core/platform/logging.h"

namespace xla {
namespace {

class TransposeFoldingTest : public HloTestBase {
 protected:
  void FoldTranspose(HloModule* module) {
    TransposeFolding transpose_folding(
        [](const HloInstruction& dot,
           const TransposeFolding::OperandIndices& candidate_operands) {
          return candidate_operands;
        },
        [](const HloInstruction& convolution,
           const TransposeFolding::OperandIndices& candidate_operands) {
          return candidate_operands;
        });
    EXPECT_IS_OK(transpose_folding.Run(module).status());
  }
};

TEST_F(TransposeFoldingTest, FoldDotTranspose) {
  auto builder = HloComputation::Builder("entry_computation");
  HloInstruction* x = builder.AddInstruction(HloInstruction::CreateParameter(
      /*parameter_number=*/0, ShapeUtil::MakeShape(F32, {2, 3}),
      /*name=*/"x"));
  HloInstruction* y = builder.AddInstruction(HloInstruction::CreateParameter(
      /*parameter_number=*/1, ShapeUtil::MakeShape(F32, {2, 3}),
      /*name=*/"y"));
  HloInstruction* transpose_y =
      builder.AddInstruction(HloInstruction::CreateTranspose(
          ShapeUtil::MakeShape(F32, {3, 2}), y, {1, 0}));
  HloInstruction* dot = builder.AddInstruction(HloInstruction::CreateBinary(
      ShapeUtil::MakeShape(F32, {2, 2}), /*opcode=*/HloOpcode::kDot,
      /*lhs=*/x, /*rhs=*/transpose_y));

  HloModule module("test_module");
  HloComputation* entry_computation =
      module.AddEntryComputation(builder.Build(dot));
  FoldTranspose(&module);

  // Instructions after folding: x, y, and the fusion.
  std::unordered_set<HloInstruction*> instruction_set(
      entry_computation->instructions().begin(),
      entry_computation->instructions().end());
  CHECK_EQ(1, instruction_set.erase(x)) << "x is not in entry_computation.";
  CHECK_EQ(1, instruction_set.erase(y)) << "y is not in entry_computation.";
  CHECK_EQ(1, instruction_set.size())
      << "entry_computation should contain exactly 3 instructions.";
  HloInstruction* fusion = *instruction_set.begin();
  EXPECT_EQ(HloOpcode::kFusion, fusion->opcode());

  // The fusion instruction should contain two parameters, one transpose and
  // one dot.
  EXPECT_EQ(4, fusion->fused_instruction_count());
}

TEST_F(TransposeFoldingTest, FoldDotTransposeConstant) {
  auto builder = HloComputation::Builder("entry_computation");
  // 2x1
  HloInstruction* const0 = builder.AddInstruction(
      HloInstruction::CreateConstant(Literal::CreateR2<float>({{1}, {2}})));
  // 3x2
  HloInstruction* const1 =
      builder.AddInstruction(HloInstruction::CreateConstant(
          Literal::CreateR2<float>({{1, 2}, {3, 4}, {5, 6}})));
  HloInstruction* transpose0 =
      builder.AddInstruction(HloInstruction::CreateTranspose(
          ShapeUtil::MakeShape(F32, {1, 2}), const0, {1, 0}));
  HloInstruction* transpose1 =
      builder.AddInstruction(HloInstruction::CreateTranspose(
          ShapeUtil::MakeShape(F32, {2, 3}), const1, {1, 0}));
  HloInstruction* dot = builder.AddInstruction(HloInstruction::CreateBinary(
      ShapeUtil::MakeShape(F32, {1, 3}), /*opcode=*/HloOpcode::kDot,
      /*lhs=*/transpose0, /*rhs=*/transpose1));

  HloModule module("test_module");
  HloComputation* entry_computation =
      module.AddEntryComputation(builder.Build(dot));
  FoldTranspose(&module);

  for (auto* instruction : entry_computation->instructions()) {
    if (instruction->opcode() == HloOpcode::kFusion) {
      CHECK_EQ(2, instruction->operand_count());
      EXPECT_EQ(const0, instruction->operand(0));
      EXPECT_EQ(const1, instruction->operand(1));
    }
  }

  // The created fusion instruction should contain two parameters, two
  // transposes (one for each parameter) and one dot.
  EXPECT_EQ(5,
            entry_computation->root_instruction()->fused_instruction_count());
}

TEST_F(TransposeFoldingTest, FuseDotWithConstantOperands) {
  auto builder = HloComputation::Builder("entry");
  // (1.0 + 2.0) * (2.0 - 3.0)
  HloInstruction* const1 = builder.AddInstruction(
      HloInstruction::CreateConstant(Literal::CreateR0<float>(1.0)));
  HloInstruction* const2 = builder.AddInstruction(
      HloInstruction::CreateConstant(Literal::CreateR0<float>(2.0)));
  HloInstruction* const3 = builder.AddInstruction(
      HloInstruction::CreateConstant(Literal::CreateR0<float>(3.0)));
  HloInstruction* add = builder.AddInstruction(HloInstruction::CreateBinary(
      const1->shape(), HloOpcode::kAdd, const1, const2));
  HloInstruction* sub = builder.AddInstruction(HloInstruction::CreateBinary(
      const2->shape(), HloOpcode::kSubtract, const2, const3));
  HloInstruction* mul = builder.AddInstruction(HloInstruction::CreateBinary(
      add->shape(), HloOpcode::kMultiply, add, sub));

  HloModule module("fuse_with_constant_operands");
  HloComputation* entry_computation =
      module.AddEntryComputation(builder.Build(mul));
  HloInstruction* call = module.OutlineExpressionFromComputation(
      {add, sub, mul}, "", entry_computation);
  EXPECT_EQ(call, entry_computation->root_instruction());
  HloComputation* callee_computation = call->to_apply();
  // The arguments to the call should be const1, const2, and const3.
  EXPECT_THAT(call->operands(),
              ::testing::UnorderedElementsAre(const1, const2, const3));

  // The callee should contain 3 parameters and 3 binary operators.
  EXPECT_EQ(6, callee_computation->instruction_count());
}

TEST_F(TransposeFoldingTest, FoldDotTransposeInWhile) {
  auto builder = HloComputation::Builder("entry_computation");
  HloInstruction* x = builder.AddInstruction(HloInstruction::CreateParameter(
      /*parameter_number=*/0, ShapeUtil::MakeShape(F32, {2, 3}),
      /*name=*/"x"));
  HloInstruction* y = builder.AddInstruction(HloInstruction::CreateParameter(
      /*parameter_number=*/1, ShapeUtil::MakeShape(F32, {2, 3}),
      /*name=*/"y"));
  HloInstruction* transpose_y =
      builder.AddInstruction(HloInstruction::CreateTranspose(
          ShapeUtil::MakeShape(F32, {3, 2}), y, {1, 0}));
  HloInstruction* dot = builder.AddInstruction(HloInstruction::CreateBinary(
      ShapeUtil::MakeShape(F32, {2, 2}), /*opcode=*/HloOpcode::kDot,
      /*lhs=*/x, /*rhs=*/transpose_y));

  HloModule module("test_module");
  HloComputation* entry_computation =
      module.AddEntryComputation(builder.Build(dot));

  HloInstruction* call = module.OutlineExpressionFromComputation(
      {transpose_y, dot}, "outlined", entry_computation);

  FoldTranspose(&module);

  // Instructions after folding: x, y, and the fusion.
  std::unordered_set<HloInstruction*> instruction_set(
      entry_computation->instructions().begin(),
      entry_computation->instructions().end());
  CHECK_EQ(1, instruction_set.erase(x)) << "x is not in entry_computation.";
  CHECK_EQ(1, instruction_set.erase(y)) << "y is not in entry_computation.";
  CHECK_EQ(1, instruction_set.erase(call))
      << "call is not in entry_computation.";
  CHECK(instruction_set.empty())
      << "entry_computation should contain exactly 3 instructions.";
  HloInstruction* fusion =
      call->called_computations().front()->root_instruction();
  EXPECT_EQ(HloOpcode::kFusion, fusion->opcode());

  // The fusion instruction should contain two parameters, one transpose and
  // one dot.
  EXPECT_EQ(4, fusion->fused_instruction_count());
}

// Test that a two dimension swap of the kernel gets folded into convolution.
TEST_F(TransposeFoldingTest, FoldConvDimSwapTransposeRhs) {
  auto builder = HloComputation::Builder("entry_computation");
  HloInstruction* x = builder.AddInstruction(HloInstruction::CreateParameter(
      /*parameter_number=*/0, ShapeUtil::MakeShape(F32, {2, 3, 1, 1}),
      /*name=*/"x"));
  HloInstruction* y = builder.AddInstruction(HloInstruction::CreateParameter(
      /*parameter_number=*/1, ShapeUtil::MakeShape(F32, {3, 2, 1, 1}),
      /*name=*/"y"));
  HloInstruction* transpose_y =
      builder.AddInstruction(HloInstruction::CreateTranspose(
          ShapeUtil::MakeShape(F32, {2, 3, 1, 1}), y, {1, 0, 2, 3}));
  auto dnums = ComputationBuilder::CreateDefaultConvDimensionNumbers();
  Window window;
  for (int i = 0; i < 2; ++i) {
    WindowDimension* dim = window.add_dimensions();
    dim->set_padding_low(0);
    dim->set_padding_high(0);
    dim->set_base_dilation(1);
    dim->set_window_dilation(1);
    dim->set_stride(1);
    dim->set_size(
        transpose_y->shape().dimensions(dnums.kernel_spatial_dimensions(i)));
  }
  StatusOr<Shape> conv_shape = ShapeInference::InferConvolveShape(
      x->shape(), transpose_y->shape(), window, dnums);
  EXPECT_IS_OK(conv_shape);
  HloInstruction* conv = builder.AddInstruction(HloInstruction::CreateConvolve(
      conv_shape.ValueOrDie(), x, transpose_y, window, dnums));

  HloModule module("test_module");
  HloComputation* entry_computation =
      module.AddEntryComputation(builder.Build(conv));
  FoldTranspose(&module);

  // Instructions after folding: x, y, and the convolution.
  std::unordered_set<HloInstruction*> instruction_set(
      entry_computation->instructions().begin(),
      entry_computation->instructions().end());
  CHECK_EQ(1, instruction_set.erase(x)) << "x is not in entry_computation.";
  CHECK_EQ(1, instruction_set.erase(y)) << "y is not in entry_computation.";
  CHECK_EQ(1, instruction_set.size())
      << "entry_computation should contain exactly 3 instructions.";
  HloInstruction* new_conv = *instruction_set.begin();
  EXPECT_EQ(HloOpcode::kConvolution, new_conv->opcode());
  EXPECT_EQ(dnums.kernel_input_feature_dimension(),
            new_conv->convolution_dimension_numbers()
                .kernel_output_feature_dimension());
  EXPECT_EQ(dnums.kernel_output_feature_dimension(),
            new_conv->convolution_dimension_numbers()
                .kernel_input_feature_dimension());
}

// Test that a complex transpose of the kernel gets folded into convolution.
TEST_F(TransposeFoldingTest, FoldConvComplexTransposeRhs) {
  auto builder = HloComputation::Builder("entry_computation");
  HloInstruction* x = builder.AddInstruction(HloInstruction::CreateParameter(
      /*parameter_number=*/0, ShapeUtil::MakeShape(F32, {2, 3, 1, 1}),
      /*name=*/"x"));
  HloInstruction* y = builder.AddInstruction(HloInstruction::CreateParameter(
      /*parameter_number=*/1, ShapeUtil::MakeShape(F32, {1, 2, 1, 3}),
      /*name=*/"y"));
  HloInstruction* transpose_y =
      builder.AddInstruction(HloInstruction::CreateTranspose(
          ShapeUtil::MakeShape(F32, {2, 3, 1, 1}), y, {1, 3, 0, 2}));
  auto dnums = ComputationBuilder::CreateDefaultConvDimensionNumbers();
  Window window;
  for (int i = 0; i < 2; ++i) {
    WindowDimension* dim = window.add_dimensions();
    dim->set_padding_low(0);
    dim->set_padding_high(0);
    dim->set_base_dilation(1);
    dim->set_window_dilation(1);
    dim->set_stride(1);
    dim->set_size(
        transpose_y->shape().dimensions(dnums.kernel_spatial_dimensions(i)));
  }
  StatusOr<Shape> conv_shape = ShapeInference::InferConvolveShape(
      x->shape(), transpose_y->shape(), window, dnums);
  EXPECT_IS_OK(conv_shape);
  HloInstruction* conv = builder.AddInstruction(HloInstruction::CreateConvolve(
      conv_shape.ValueOrDie(), x, transpose_y, window, dnums));

  HloModule module("test_module");
  HloComputation* entry_computation =
      module.AddEntryComputation(builder.Build(conv));
  FoldTranspose(&module);

  // Instructions after folding: x, y, and the convolution.
  std::unordered_set<HloInstruction*> instruction_set(
      entry_computation->instructions().begin(),
      entry_computation->instructions().end());
  CHECK_EQ(1, instruction_set.erase(x)) << "x is not in entry_computation.";
  CHECK_EQ(1, instruction_set.erase(y)) << "y is not in entry_computation.";
  CHECK_EQ(1, instruction_set.size())
      << "entry_computation should contain exactly 3 instructions.";
  HloInstruction* new_conv = *instruction_set.begin();
  EXPECT_EQ(HloOpcode::kConvolution, new_conv->opcode());
  EXPECT_EQ(dnums.kernel_input_feature_dimension(),
            new_conv->convolution_dimension_numbers()
                .kernel_output_feature_dimension());
  EXPECT_EQ(dnums.kernel_spatial_dimensions(1),
            new_conv->convolution_dimension_numbers()
                .kernel_input_feature_dimension());
  EXPECT_EQ(
      dnums.kernel_output_feature_dimension(),
      new_conv->convolution_dimension_numbers().kernel_spatial_dimensions(0));
  EXPECT_EQ(
      dnums.kernel_spatial_dimensions(0),
      new_conv->convolution_dimension_numbers().kernel_spatial_dimensions(1));
}

// Test that a transpose of the activations does not get folded into
// convolution.
TEST_F(TransposeFoldingTest, FoldConvTransposeLhs) {
  auto builder = HloComputation::Builder("entry_computation");
  HloInstruction* x = builder.AddInstruction(HloInstruction::CreateParameter(
      /*parameter_number=*/0, ShapeUtil::MakeShape(F32, {3, 2, 1, 1}),
      /*name=*/"x"));
  HloInstruction* y = builder.AddInstruction(HloInstruction::CreateParameter(
      /*parameter_number=*/1, ShapeUtil::MakeShape(F32, {2, 3, 1, 1}),
      /*name=*/"y"));
  HloInstruction* transpose_x =
      builder.AddInstruction(HloInstruction::CreateTranspose(
          ShapeUtil::MakeShape(F32, {2, 3, 1, 1}), x, {1, 0, 2, 3}));
  auto dnums = ComputationBuilder::CreateDefaultConvDimensionNumbers();
  Window window;
  for (int i = 0; i < 2; ++i) {
    WindowDimension* dim = window.add_dimensions();
    dim->set_padding_low(0);
    dim->set_padding_high(0);
    dim->set_base_dilation(1);
    dim->set_window_dilation(1);
    dim->set_stride(1);
    dim->set_size(y->shape().dimensions(dnums.kernel_spatial_dimensions(i)));
  }
  StatusOr<Shape> conv_shape = ShapeInference::InferConvolveShape(
      transpose_x->shape(), y->shape(), window, dnums);
  EXPECT_IS_OK(conv_shape);
  HloInstruction* conv = builder.AddInstruction(HloInstruction::CreateConvolve(
      conv_shape.ValueOrDie(), transpose_x, y, window, dnums));

  HloModule module("test_module");
  HloComputation* entry_computation =
      module.AddEntryComputation(builder.Build(conv));
  FoldTranspose(&module);

  // Instructions after folding: transpose_x, y, and the convolution.
  std::unordered_set<HloInstruction*> instruction_set(
      entry_computation->instructions().begin(),
      entry_computation->instructions().end());
  CHECK_EQ(1, instruction_set.erase(x)) << "x is not in entry_computation.";
  CHECK_EQ(1, instruction_set.erase(y)) << "y is not in entry_computation.";
  CHECK_EQ(1, instruction_set.erase(transpose_x))
      << "transpose_x is not in entry_computation.";
  CHECK_EQ(1, instruction_set.erase(conv))
      << "transpose_x is not in entry_computation.";
  CHECK_EQ(0, instruction_set.size())
      << "entry_computation should contain exactly 4 instructions.";
}

}  // namespace
}  // namespace xla
