text: // Copyright 2014 the V8 project authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  
  #include <limits>
  
  #include "src/compiler/node-matchers.h"
  #include "src/compiler/representation-change.h"
  #include "src/compiler/type-cache.h"
  #include "src/objects-inl.h"
  #include "test/cctest/cctest.h"
  #include "test/cctest/compiler/codegen-tester.h"
  #include "test/cctest/compiler/graph-builder-tester.h"
  #include "test/cctest/compiler/value-helper.h"
  
  namespace v8 {
  namespace internal {
  namespace compiler {
  
  class RepresentationChangerTester : public HandleAndZoneScope,
                                      public GraphAndBuilders {
   public:
    explicit RepresentationChangerTester(int num_parameters = 0)
        : GraphAndBuilders(main_zone()),
          javascript_(main_zone()),
          jsgraph_(main_isolate(), main_graph_, &main_common_, &javascript_,
                   &main_simplified_, &main_machine_),
          changer_(&jsgraph_, main_isolate()) {
      Node* s = graph()->NewNode(common()->Start(num_parameters));
      graph()->SetStart(s);
    }
  
    JSOperatorBuilder javascript_;
    JSGraph jsgraph_;
    RepresentationChanger changer_;
  
    Isolate* isolate() { return main_isolate(); }
    Graph* graph() { return main_graph_; }
    CommonOperatorBuilder* common() { return &main_common_; }
    JSGraph* jsgraph() { return &jsgraph_; }
    RepresentationChanger* changer() { return &changer_; }
  
    // TODO(titzer): use ValueChecker / ValueUtil
    void CheckInt32Constant(Node* n, int32_t expected) {
      Int32Matcher m(n);
      CHECK(m.HasValue());
      CHECK_EQ(expected, m.Value());
    }
  
    void CheckInt64Constant(Node* n, int64_t expected) {
      Int64Matcher m(n);
      CHECK(m.HasValue());
      CHECK_EQ(expected, m.Value());
    }
  
    void CheckUint32Constant(Node* n, uint32_t expected) {
      Uint32Matcher m(n);
      CHECK(m.HasValue());
      CHECK_EQ(static_cast<int>(expected), static_cast<int>(m.Value()));
    }
  
    void CheckFloat64Constant(Node* n, double expected) {
      Float64Matcher m(n);
      CHECK(m.HasValue());
      CHECK_DOUBLE_EQ(expected, m.Value());
    }
  
    void CheckFloat32Constant(Node* n, float expected) {
      CHECK_EQ(IrOpcode::kFloat32Constant, n->opcode());
      float fval = OpParameter<float>(n->op());
      CHECK_FLOAT_EQ(expected, fval);
    }
  
    void CheckHeapConstant(Node* n, HeapObject* expected) {
      HeapObjectMatcher m(n);
      CHECK(m.HasValue());
      CHECK_EQ(expected, *m.Value());
    }
  
    void CheckNumberConstant(Node* n, double expected) {
      NumberMatcher m(n);
      CHECK_EQ(IrOpcode::kNumberConstant, n->opcode());
      CHECK(m.HasValue());
      CHECK_DOUBLE_EQ(expected, m.Value());
    }
  
    Node* Parameter(int index = 0) {
      Node* n = graph()->NewNode(common()->Parameter(index), graph()->start());
      NodeProperties::SetType(n, Type::Any());
      return n;
    }
  
    Node* Return(Node* input) {
      Node* n = graph()->NewNode(common()->Return(), jsgraph()->Int32Constant(0),
                                 input, graph()->start(), graph()->start());
      return n;
    }
  
    void CheckTypeError(MachineRepresentation from, Type from_type,
                        MachineRepresentation to) {
      changer()->testing_type_errors_ = true;
      changer()->type_error_ = false;
      Node* n = Parameter(0);
      Node* use = Return(n);
      Node* c = changer()->GetRepresentationFor(n, from, from_type, use,
                                                UseInfo(to, Truncation::None()));
      CHECK(changer()->type_error_);
      CHECK_EQ(n, c);
    }
  
    void CheckNop(MachineRepresentation from, Type from_type,
                  MachineRepresentation to) {
      Node* n = Parameter(0);
      Node* use = Return(n);
      Node* c = changer()->GetRepresentationFor(n, from, from_type, use,
                                                UseInfo(to, Truncation::None()));
      CHECK_EQ(n, c);
    }
  };
  
  
  const MachineType kMachineTypes[] = {
      MachineType::Float32(), MachineType::Float64(),  MachineType::Int8(),
      MachineType::Uint8(),   MachineType::Int16(),    MachineType::Uint16(),
      MachineType::Int32(),   MachineType::Uint32(),   MachineType::Int64(),
      MachineType::Uint64(),  MachineType::AnyTagged()};
  
  
  TEST(BoolToBit_constant) {
    RepresentationChangerTester r;
  
    Node* true_node = r.jsgraph()->TrueConstant();
    Node* true_use = r.Return(true_node);
    Node* true_bit = r.changer()->GetRepresentationFor(
        true_node, MachineRepresentation::kTagged, Type::None(), true_use,
        UseInfo(MachineRepresentation::kBit, Truncation::None()));
    r.CheckInt32Constant(true_bit, 1);
  
    Node* false_node = r.jsgraph()->FalseConstant();
    Node* false_use = r.Return(false_node);
    Node* false_bit = r.changer()->GetRepresentationFor(
        false_node, MachineRepresentation::kTagged, Type::None(), false_use,
        UseInfo(MachineRepresentation::kBit, Truncation::None()));
    r.CheckInt32Constant(false_bit, 0);
  }
  
  TEST(ToTagged_constant) {
    RepresentationChangerTester r;
  
    for (double i : ValueHelper::float64_vector()) {
      Node* n = r.jsgraph()->Constant(i);
      Node* use = r.Return(n);
      Node* c = r.changer()->GetRepresentationFor(
          n, MachineRepresentation::kFloat64, Type::None(), use,
          UseInfo(MachineRepresentation::kTagged, Truncation::None()));
      r.CheckNumberConstant(c, i);
    }
  
    for (int i : ValueHelper::int32_vector()) {
      Node* n = r.jsgraph()->Constant(i);
      Node* use = r.Return(n);
      Node* c = r.changer()->GetRepresentationFor(
          n, MachineRepresentation::kWord32, Type::Signed32(), use,
          UseInfo(MachineRepresentation::kTagged, Truncation::None()));
      r.CheckNumberConstant(c, i);
    }
  
    for (uint32_t i : ValueHelper::uint32_vector()) {
      Node* n = r.jsgraph()->Constant(i);
      Node* use = r.Return(n);
      Node* c = r.changer()->GetRepresentationFor(
          n, MachineRepresentation::kWord32, Type::Unsigned32(), use,
          UseInfo(MachineRepresentation::kTagged, Truncation::None()));
      r.CheckNumberConstant(c, i);
    }
  }
  
  TEST(ToFloat64_constant) {
    RepresentationChangerTester r;
  
    for (double i : ValueHelper::float64_vector()) {
      Node* n = r.jsgraph()->Constant(i);
      Node* use = r.Return(n);
      Node* c = r.changer()->GetRepresentationFor(
          n, MachineRepresentation::kTagged, Type::None(), use,
          UseInfo(MachineRepresentation::kFloat64, Truncation::None()));
      r.CheckFloat64Constant(c, i);
    }
  
    for (int i : ValueHelper::int32_vector()) {
      Node* n = r.jsgraph()->Constant(i);
      Node* use = r.Return(n);
      Node* c = r.changer()->GetRepresentationFor(
          n, MachineRepresentation::kWord32, Type::Signed32(), use,
          UseInfo(MachineRepresentation::kFloat64, Truncation::None()));
      r.CheckFloat64Constant(c, i);
    }
  
    for (uint32_t i : ValueHelper::uint32_vector()) {
      Node* n = r.jsgraph()->Constant(i);
      Node* use = r.Return(n);
      Node* c = r.changer()->GetRepresentationFor(
          n, MachineRepresentation::kWord32, Type::Unsigned32(), use,
          UseInfo(MachineRepresentation::kFloat64, Truncation::None()));
      r.CheckFloat64Constant(c, i);
    }
  
    {
      Node* n = r.jsgraph()->Constant(0);
      Node* use = r.Return(n);
      Node* c = r.changer()->GetRepresentationFor(
          n, MachineRepresentation::kWord64, Type::Range(0, 0, r.zone()), use,
          UseInfo(MachineRepresentation::kFloat64, Truncation::None()));
      r.CheckFloat64Constant(c, 0);
    }
  }
  
  
  static bool IsFloat32Int32(int32_t val) {
    return val >= -(1 << 23) && val <= (1 << 23);
  }
  
  
  static bool IsFloat32Uint32(uint32_t val) { return val <= (1 << 23); }
  
  
  TEST(ToFloat32_constant) {
    RepresentationChangerTester r;
  
    for (double i : ValueHelper::float32_vector()) {
      Node* n = r.jsgraph()->Constant(i);
      Node* use = r.Return(n);
      Node* c = r.changer()->GetRepresentationFor(
          n, MachineRepresentation::kTagged, Type::None(), use,
          UseInfo(MachineRepresentation::kFloat32, Truncation::None()));
      r.CheckFloat32Constant(c, i);
    }
  
    for (int i : ValueHelper::int32_vector()) {
      if (!IsFloat32Int32(i)) continue;
      Node* n = r.jsgraph()->Constant(i);
      Node* use = r.Return(n);
      Node* c = r.changer()->GetRepresentationFor(
          n, MachineRepresentation::kWord32, Type::Signed32(), use,
          UseInfo(MachineRepresentation::kFloat32, Truncation::None()));
      r.CheckFloat32Constant(c, static_cast<float>(i));
    }
  
    for (uint32_t i : ValueHelper::uint32_vector()) {
      if (!IsFloat32Uint32(i)) continue;
      Node* n = r.jsgraph()->Constant(i);
      Node* use = r.Return(n);
      Node* c = r.changer()->GetRepresentationFor(
          n, MachineRepresentation::kWord32, Type::Unsigned32(), use,
          UseInfo(MachineRepresentation::kFloat32, Truncation::None()));
      r.CheckFloat32Constant(c, static_cast<float>(i));
    }
  }
  
  TEST(ToInt32_constant) {
    RepresentationChangerTester r;
    {
      FOR_INT32_INPUTS(i) {
        Node* n = r.jsgraph()->Constant(*i);
        Node* use = r.Return(n);
        Node* c = r.changer()->GetRepresentationFor(
            n, MachineRepresentation::kTagged, Type::Signed32(), use,
            UseInfo(MachineRepresentation::kWord32, Truncation::None()));
        r.CheckInt32Constant(c, *i);
      }
    }
  }
  
  TEST(ToUint32_constant) {
    RepresentationChangerTester r;
    FOR_UINT32_INPUTS(i) {
      Node* n = r.jsgraph()->Constant(static_cast<double>(*i));
      Node* use = r.Return(n);
      Node* c = r.changer()->GetRepresentationFor(
          n, MachineRepresentation::kTagged, Type::Unsigned32(), use,
          UseInfo(MachineRepresentation::kWord32, Truncation::None()));
      r.CheckUint32Constant(c, *i);
    }
  }
  
  TEST(ToInt64_constant) {
    RepresentationChangerTester r;
    FOR_INT32_INPUTS(i) {
      Node* n = r.jsgraph()->Constant(*i);
      Node* use = r.Return(n);
      Node* c = r.changer()->GetRepresentationFor(
          n, MachineRepresentation::kTagged, TypeCache::Get().kSafeInteger, use,
          UseInfo(MachineRepresentation::kWord64, Truncation::None()));
      r.CheckInt64Constant(c, *i);
    }
  }
  
  static void CheckChange(IrOpcode::Value expected, MachineRepresentation from,
                          Type from_type, UseInfo use_info) {
    RepresentationChangerTester r;
  
    Node* n = r.Parameter();
    Node* use = r.Return(n);
    Node* c =
        r.changer()->GetRepresentationFor(n, from, from_type, use, use_info);
  
    CHECK_NE(c, n);
    CHECK_EQ(expected, c->opcode());
    CHECK_EQ(n, c->InputAt(0));
  
    if (expected == IrOpcode::kCheckedFloat64ToInt32 ||
        expected == IrOpcode::kCheckedFloat64ToInt64) {
      CheckForMinusZeroMode mode =
          from_type.Maybe(Type::MinusZero())
              ? use_info.minus_zero_check()
              : CheckForMinusZeroMode::kDontCheckForMinusZero;
      CHECK_EQ(mode, CheckMinusZeroParametersOf(c->op()).mode());
    }
  }
  
  static void CheckChange(IrOpcode::Value expected, MachineRepresentation from,
                          Type from_type, MachineRepresentation to) {
    CheckChange(expected, from, from_type, UseInfo(to, Truncation::Any()));
  }
  
  static void CheckTwoChanges(IrOpcode::Value expected2,
                              IrOpcode::Value expected1,
                              MachineRepresentation from, Type from_type,
                              MachineRepresentation to, UseInfo use_info) {
    RepresentationChangerTester r;
  
    Node* n = r.Parameter();
    Node* use = r.Return(n);
    Node* c1 =
        r.changer()->GetRepresentationFor(n, from, from_type, use, use_info);
  
    CHECK_NE(c1, n);
    CHECK_EQ(expected1, c1->opcode());
    Node* c2 = c1->InputAt(0);
    CHECK_NE(c2, n);
    CHECK_EQ(expected2, c2->opcode());
    CHECK_EQ(n, c2->InputAt(0));
  }
  
  static void CheckTwoChanges(IrOpcode::Value expected2,
                              IrOpcode::Value expected1,
                              MachineRepresentation from, Type from_type,
                              MachineRepresentation to) {
    CheckTwoChanges(expected2, expected1, from, from_type, to,
                    UseInfo(to, Truncation::None()));
  }
  
  static void CheckChange(IrOpcode::Value expected, MachineRepresentation from,
                          Type from_type, MachineRepresentation to,
                          UseInfo use_info) {
    RepresentationChangerTester r;
  
    Node* n = r.Parameter();
    Node* use = r.Return(n);
    Node* c =
        r.changer()->GetRepresentationFor(n, from, from_type, use, use_info);
  
    CHECK_NE(c, n);
    CHECK_EQ(expected, c->opcode());
    CHECK_EQ(n, c->InputAt(0));
  }
  
  TEST(Word64) {
    CheckChange(IrOpcode::kChangeInt32ToInt64, MachineRepresentation::kWord8,
                TypeCache::Get().kInt8, MachineRepresentation::kWord64);
    CheckChange(IrOpcode::kChangeUint32ToUint64, MachineRepresentation::kWord8,
                TypeCache::Get().kUint8, MachineRepresentation::kWord64);
    CheckChange(IrOpcode::kChangeInt32ToInt64, MachineRepresentation::kWord16,
                TypeCache::Get().kInt16, MachineRepresentation::kWord64);
    CheckChange(IrOpcode::kChangeUint32ToUint64, MachineRepresentation::kWord16,
                TypeCache::Get().kUint16, MachineRepresentation::kWord64);
    CheckChange(IrOpcode::kChangeInt32ToInt64, MachineRepresentation::kWord32,
                Type::Signed32(), MachineRepresentation::kWord64);
    CheckChange(IrOpcode::kChangeUint32ToUint64, MachineRepresentation::kWord32,
                Type::Unsigned32(), MachineRepresentation::kWord64);
  
    CheckChange(IrOpcode::kTruncateInt64ToInt32, MachineRepresentation::kWord64,
                Type::Signed32(), MachineRepresentation::kWord32);
    CheckChange(IrOpcode::kTruncateInt64ToInt32, MachineRepresentation::kWord64,
                Type::Unsigned32(), MachineRepresentation::kWord32);
    CheckChange(IrOpcode::kTruncateInt64ToInt32, MachineRepresentation::kWord64,
                TypeCache::Get().kSafeInteger, MachineRepresentation::kWord32,
                UseInfo::TruncatingWord32());
    CheckChange(
        IrOpcode::kCheckedInt64ToInt32, MachineRepresentation::kWord64,
        TypeCache::Get().kSafeInteger, MachineRepresentation::kWord32,
        UseInfo::CheckedSigned32AsWord32(kIdentifyZeros, VectorSlotPair()));
    CheckChange(
        IrOpcode::kCheckedUint64ToInt32, MachineRepresentation::kWord64,
        TypeCache::Get().kPositiveSafeInteger, MachineRepresentation::kWord32,
        UseInfo::CheckedSigned32AsWord32(kIdentifyZeros, VectorSlotPair()));
  
    CheckChange(IrOpcode::kChangeFloat64ToInt64, MachineRepresentation::kFloat64,
                Type::Signed32(), MachineRepresentation::kWord64);
    CheckChange(IrOpcode::kChangeFloat64ToInt64, MachineRepresentation::kFloat64,
                Type::Unsigned32(), MachineRepresentation::kWord64);
    CheckChange(IrOpcode::kChangeFloat64ToInt64, MachineRepresentation::kFloat64,
                TypeCache::Get().kSafeInteger, MachineRepresentation::kWord64);
    CheckChange(IrOpcode::kChangeFloat64ToInt64, MachineRepresentation::kFloat64,
                TypeCache::Get().kInt64, MachineRepresentation::kWord64);
    CheckChange(IrOpcode::kChangeFloat64ToUint64, MachineRepresentation::kFloat64,
                TypeCache::Get().kUint64, MachineRepresentation::kWord64);
    CheckChange(
        IrOpcode::kCheckedFloat64ToInt64, MachineRepresentation::kFloat64,
        Type::Number(), MachineRepresentation::kWord64,
        UseInfo::CheckedSigned64AsWord64(kIdentifyZeros, VectorSlotPair()));
  
    CheckChange(IrOpcode::kChangeInt64ToFloat64, MachineRepresentation::kWord64,
                Type::Signed32(), MachineRepresentation::kFloat64);
    CheckChange(IrOpcode::kChangeInt64ToFloat64, MachineRepresentation::kWord64,
                Type::Unsigned32(), MachineRepresentation::kFloat64);
    CheckChange(IrOpcode::kChangeInt64ToFloat64, MachineRepresentation::kWord64,
                TypeCache::Get().kSafeInteger, MachineRepresentation::kFloat64);
  
    CheckTwoChanges(IrOpcode::kChangeFloat32ToFloat64,
                    IrOpcode::kChangeFloat64ToInt64,
                    MachineRepresentation::kFloat32, Type::Signed32(),
                    MachineRepresentation::kWord64);
    CheckTwoChanges(IrOpcode::kChangeFloat32ToFloat64,
                    IrOpcode::kChangeFloat64ToInt64,
                    MachineRepresentation::kFloat32, Type::Unsigned32(),
                    MachineRepresentation::kWord64);
    CheckTwoChanges(IrOpcode::kChangeFloat32ToFloat64,
                    IrOpcode::kChangeFloat64ToInt64,
                    MachineRepresentation::kFloat32, TypeCache::Get().kInt64,
                    MachineRepresentation::kWord64);
    CheckTwoChanges(IrOpcode::kChangeFloat32ToFloat64,
                    IrOpcode::kChangeFloat64ToUint64,
                    MachineRepresentation::kFloat32, TypeCache::Get().kUint64,
                    MachineRepresentation::kWord64);
    CheckTwoChanges(
        IrOpcode::kChangeFloat32ToFloat64, IrOpcode::kCheckedFloat64ToInt64,
        MachineRepresentation::kFloat32, Type::Number(),
        MachineRepresentation::kWord64,
        UseInfo::CheckedSigned64AsWord64(kIdentifyZeros, VectorSlotPair()));
  
    CheckTwoChanges(IrOpcode::kChangeInt64ToFloat64,
                    IrOpcode::kTruncateFloat64ToFloat32,
                    MachineRepresentation::kWord64, Type::Signed32(),
                    MachineRepresentation::kFloat32);
  
    CheckChange(IrOpcode::kChangeTaggedToInt64, MachineRepresentation::kTagged,
                Type::Signed32(), MachineRepresentation::kWord64);
    CheckChange(IrOpcode::kChangeTaggedToInt64, MachineRepresentation::kTagged,
                Type::Unsigned32(), MachineRepresentation::kWord64);
    CheckChange(IrOpcode::kChangeTaggedToInt64, MachineRepresentation::kTagged,
                TypeCache::Get().kSafeInteger, MachineRepresentation::kWord64);
    CheckChange(IrOpcode::kChangeTaggedToInt64, MachineRepresentation::kTagged,
                TypeCache::Get().kInt64, MachineRepresentation::kWord64);
    CheckChange(IrOpcode::kChangeTaggedSignedToInt64,
                MachineRepresentation::kTaggedSigned, Type::SignedSmall(),
                MachineRepresentation::kWord64);
    CheckChange(
        IrOpcode::kCheckedTaggedToInt64, MachineRepresentation::kTagged,
        Type::Number(), MachineRepresentation::kWord64,
        UseInfo::CheckedSigned64AsWord64(kIdentifyZeros, VectorSlotPair()));
    CheckChange(
        IrOpcode::kCheckedTaggedToInt64, MachineRepresentation::kTaggedPointer,
        Type::Number(), MachineRepresentation::kWord64,
        UseInfo::CheckedSigned64AsWord64(kIdentifyZeros, VectorSlotPair()));
  
    CheckTwoChanges(IrOpcode::kTruncateInt64ToInt32,
                    IrOpcode::kChangeInt31ToTaggedSigned,
                    MachineRepresentation::kWord64, Type::Signed31(),
                    MachineRepresentation::kTagged);
    CheckTwoChanges(IrOpcode::kTruncateInt64ToInt32,
                    IrOpcode::kChangeInt32ToTagged,
                    MachineRepresentation::kWord64, Type::Signed32(),
                    MachineRepresentation::kTagged);
    CheckTwoChanges(IrOpcode::kTruncateInt64ToInt32,
                    IrOpcode::kChangeUint32ToTagged,
                    MachineRepresentation::kWord64, Type::Unsigned32(),
                    MachineRepresentation::kTagged);
    CheckChange(IrOpcode::kChangeInt64ToTagged, MachineRepresentation::kWord64,
                TypeCache::Get().kSafeInteger, MachineRepresentation::kTagged);
    CheckChange(IrOpcode::kChangeUint64ToTagged, MachineRepresentation::kWord64,
                TypeCache::Get().kPositiveSafeInteger,
                MachineRepresentation::kTagged);
  
    CheckTwoChanges(IrOpcode::kTruncateInt64ToInt32,
                    IrOpcode::kChangeInt31ToTaggedSigned,
                    MachineRepresentation::kWord64, Type::Signed31(),
                    MachineRepresentation::kTaggedSigned);
    if (SmiValuesAre32Bits()) {
      CheckTwoChanges(IrOpcode::kTruncateInt64ToInt32,
                      IrOpcode::kChangeInt32ToTagged,
                      MachineRepresentation::kWord64, Type::Signed32(),
                      MachineRepresentation::kTaggedSigned);
    }
    CheckChange(IrOpcode::kCheckedInt64ToTaggedSigned,
                MachineRepresentation::kWord64, TypeCache::Get().kSafeInteger,
                MachineRepresentation::kTaggedSigned,
                UseInfo::CheckedSignedSmallAsTaggedSigned(VectorSlotPair()));
    CheckChange(IrOpcode::kCheckedUint64ToTaggedSigned,
                MachineRepresentation::kWord64,
                TypeCache::Get().kPositiveSafeInteger,
                MachineRepresentation::kTaggedSigned,
                UseInfo::CheckedSignedSmallAsTaggedSigned(VectorSlotPair()));
  
    CheckTwoChanges(IrOpcode::kChangeInt64ToFloat64,
                    IrOpcode::kChangeFloat64ToTaggedPointer,
                    MachineRepresentation::kWord64, TypeCache::Get().kSafeInteger,
                    MachineRepresentation::kTaggedPointer);
  }
  
  TEST(SingleChanges) {
    CheckChange(IrOpcode::kChangeTaggedToBit, MachineRepresentation::kTagged,
                Type::Boolean(), MachineRepresentation::kBit);
    CheckChange(IrOpcode::kChangeBitToTagged, MachineRepresentation::kBit,
                Type::Boolean(), MachineRepresentation::kTagged);
  
    CheckChange(IrOpcode::kChangeInt31ToTaggedSigned,
                MachineRepresentation::kWord32, Type::Signed31(),
                MachineRepresentation::kTagged);
    CheckChange(IrOpcode::kChangeInt32ToTagged, MachineRepresentation::kWord32,
                Type::Signed32(), MachineRepresentation::kTagged);
    CheckChange(IrOpcode::kChangeUint32ToTagged, MachineRepresentation::kWord32,
                Type::Unsigned32(), MachineRepresentation::kTagged);
    CheckChange(IrOpcode::kChangeFloat64ToTagged, MachineRepresentation::kFloat64,
                Type::Number(), MachineRepresentation::kTagged);
    CheckTwoChanges(IrOpcode::kChangeFloat64ToInt32,
                    IrOpcode::kChangeInt31ToTaggedSigned,
                    MachineRepresentation::kFloat64, Type::Signed31(),
                    MachineRepresentation::kTagged);
    CheckTwoChanges(IrOpcode::kChangeFloat64ToInt32,
                    IrOpcode::kChangeInt32ToTagged,
                    MachineRepresentation::kFloat64, Type::Signed32(),
                    MachineRepresentation::kTagged);
    CheckTwoChanges(IrOpcode::kChangeFloat64ToUint32,
                    IrOpcode::kChangeUint32ToTagged,
                    MachineRepresentation::kFloat64, Type::Unsigned32(),
                    MachineRepresentation::kTagged);
  
    CheckChange(IrOpcode::kChangeTaggedToInt32, MachineRepresentation::kTagged,
                Type::Signed32(), MachineRepresentation::kWord32);
    CheckChange(IrOpcode::kChangeTaggedToUint32, MachineRepresentation::kTagged,
                Type::Unsigned32(), MachineRepresentation::kWord32);
    CheckChange(IrOpcode::kChangeTaggedToFloat64, MachineRepresentation::kTagged,
                Type::Number(), MachineRepresentation::kFloat64);
    CheckChange(IrOpcode::kTruncateTaggedToFloat64,
                MachineRepresentation::kTagged, Type::NumberOrUndefined(),
                MachineRepresentation::kFloat64);
    CheckChange(IrOpcode::kChangeTaggedToFloat64, MachineRepresentation::kTagged,
                Type::Signed31(), MachineRepresentation::kFloat64);
  
    // Int32,Uint32 <-> Float64 are actually machine conversions.
    CheckChange(IrOpcode::kChangeInt32ToFloat64, MachineRepresentation::kWord32,
                Type::Signed32(), MachineRepresentation::kFloat64);
    CheckChange(IrOpcode::kChangeInt32ToFloat64, MachineRepresentation::kWord32,
                Type::Signed32OrMinusZero(), MachineRepresentation::kFloat64,
                UseInfo(MachineRepresentation::kFloat64,
                        Truncation::Any(kIdentifyZeros)));
    CheckChange(IrOpcode::kChangeUint32ToFloat64, MachineRepresentation::kWord32,
                Type::Unsigned32(), MachineRepresentation::kFloat64);
    CheckChange(IrOpcode::kChangeFloat64ToInt32, MachineRepresentation::kFloat64,
                Type::Signed32(), MachineRepresentation::kWord32);
    CheckChange(IrOpcode::kChangeFloat64ToUint32, MachineRepresentation::kFloat64,
                Type::Unsigned32(), MachineRepresentation::kWord32);
  
    CheckChange(IrOpcode::kTruncateFloat64ToFloat32,
                MachineRepresentation::kFloat64, Type::Number(),
                MachineRepresentation::kFloat32);
  
    // Int32,Uint32 <-> Float32 require two changes.
    CheckTwoChanges(IrOpcode::kChangeInt32ToFloat64,
                    IrOpcode::kTruncateFloat64ToFloat32,
                    MachineRepresentation::kWord32, Type::Signed32(),
                    MachineRepresentation::kFloat32);
    CheckTwoChanges(IrOpcode::kChangeUint32ToFloat64,
                    IrOpcode::kTruncateFloat64ToFloat32,
                    MachineRepresentation::kWord32, Type::Unsigned32(),
                    MachineRepresentation::kFloat32);
    CheckTwoChanges(IrOpcode::kChangeFloat32ToFloat64,
                    IrOpcode::kChangeFloat64ToInt32,
                    MachineRepresentation::kFloat32, Type::Signed32(),
                    MachineRepresentation::kWord32);
    CheckTwoChanges(IrOpcode::kChangeFloat32ToFloat64,
                    IrOpcode::kChangeFloat64ToUint32,
                    MachineRepresentation::kFloat32, Type::Unsigned32(),
                    MachineRepresentation::kWord32);
  
    // Float32 <-> Tagged require two changes.
    CheckTwoChanges(IrOpcode::kChangeFloat32ToFloat64,
                    IrOpcode::kChangeFloat64ToTagged,
                    MachineRepresentation::kFloat32, Type::Number(),
                    MachineRepresentation::kTagged);
    CheckTwoChanges(IrOpcode::kChangeTaggedToFloat64,
                    IrOpcode::kTruncateFloat64ToFloat32,
                    MachineRepresentation::kTagged, Type::Number(),
                    MachineRepresentation::kFloat32);
  }
  
  
  TEST(SignednessInWord32) {
    RepresentationChangerTester r;
  
    CheckChange(IrOpcode::kChangeTaggedToInt32, MachineRepresentation::kTagged,
                Type::Signed32(), MachineRepresentation::kWord32);
    CheckChange(IrOpcode::kChangeTaggedToUint32, MachineRepresentation::kTagged,
                Type::Unsigned32(), MachineRepresentation::kWord32);
    CheckChange(IrOpcode::kChangeInt32ToFloat64, MachineRepresentation::kWord32,
                Type::Signed32(), MachineRepresentation::kFloat64);
    CheckChange(IrOpcode::kChangeFloat64ToInt32, MachineRepresentation::kFloat64,
                Type::Signed32(), MachineRepresentation::kWord32);
    CheckChange(IrOpcode::kTruncateFloat64ToWord32,
                MachineRepresentation::kFloat64, Type::Number(),
                MachineRepresentation::kWord32,
                UseInfo(MachineRepresentation::kWord32, Truncation::Word32()));
    CheckChange(IrOpcode::kCheckedTruncateTaggedToWord32,
                MachineRepresentation::kTagged, Type::NonInternal(),
                MachineRepresentation::kWord32,
                UseInfo::CheckedNumberOrOddballAsWord32(VectorSlotPair()));
  
    CheckTwoChanges(IrOpcode::kChangeInt32ToFloat64,
                    IrOpcode::kTruncateFloat64ToFloat32,
                    MachineRepresentation::kWord32, Type::Signed32(),
                    MachineRepresentation::kFloat32);
    CheckTwoChanges(IrOpcode::kChangeFloat32ToFloat64,
                    IrOpcode::kTruncateFloat64ToWord32,
                    MachineRepresentation::kFloat32, Type::Number(),
                    MachineRepresentation::kWord32);
  
    CheckChange(
        IrOpcode::kCheckedUint32ToInt32, MachineRepresentation::kWord32,
        Type::Unsigned32(),
        UseInfo::CheckedSigned32AsWord32(kIdentifyZeros, VectorSlotPair()));
  }
  
  static void TestMinusZeroCheck(IrOpcode::Value expected, Type from_type) {
    RepresentationChangerTester r;
  
    CheckChange(
        expected, MachineRepresentation::kFloat64, from_type,
        UseInfo::CheckedSignedSmallAsWord32(kDistinguishZeros, VectorSlotPair()));
  
    CheckChange(
        expected, MachineRepresentation::kFloat64, from_type,
        UseInfo::CheckedSignedSmallAsWord32(kIdentifyZeros, VectorSlotPair()));
  
    CheckChange(
        expected, MachineRepresentation::kFloat64, from_type,
        UseInfo::CheckedSigned32AsWord32(kDistinguishZeros, VectorSlotPair()));
  
    CheckChange(
        expected, MachineRepresentation::kFloat64, from_type,
        UseInfo::CheckedSigned32AsWord32(kDistinguishZeros, VectorSlotPair()));
  }
  
  TEST(MinusZeroCheck) {
    TestMinusZeroCheck(IrOpcode::kCheckedFloat64ToInt32, Type::NumberOrOddball());
    // PlainNumber cannot be minus zero so the minus zero check should be
    // eliminated.
    TestMinusZeroCheck(IrOpcode::kCheckedFloat64ToInt32, Type::PlainNumber());
  }
  
  TEST(Nops) {
    RepresentationChangerTester r;
  
    // X -> X is always a nop for any single representation X.
    for (size_t i = 0; i < arraysize(kMachineTypes); i++) {
      r.CheckNop(kMachineTypes[i].representation(), Type::Number(),
                 kMachineTypes[i].representation());
    }
  
    // 32-bit floats.
    r.CheckNop(MachineRepresentation::kFloat32, Type::Number(),
               MachineRepresentation::kFloat32);
  
    // 32-bit words can be used as smaller word sizes and vice versa, because
    // loads from memory implicitly sign or zero extend the value to the
    // full machine word size, and stores implicitly truncate.
    r.CheckNop(MachineRepresentation::kWord32, Type::Signed32(),
               MachineRepresentation::kWord8);
    r.CheckNop(MachineRepresentation::kWord32, Type::Signed32(),
               MachineRepresentation::kWord16);
    r.CheckNop(MachineRepresentation::kWord32, Type::Signed32(),
               MachineRepresentation::kWord32);
    r.CheckNop(MachineRepresentation::kWord8, Type::Signed32(),
               MachineRepresentation::kWord32);
    r.CheckNop(MachineRepresentation::kWord16, Type::Signed32(),
               MachineRepresentation::kWord32);
  
    // kRepBit (result of comparison) is implicitly a wordish thing.
    r.CheckNop(MachineRepresentation::kBit, Type::Boolean(),
               MachineRepresentation::kWord8);
    r.CheckNop(MachineRepresentation::kBit, Type::Boolean(),
               MachineRepresentation::kWord16);
    r.CheckNop(MachineRepresentation::kBit, Type::Boolean(),
               MachineRepresentation::kWord32);
    r.CheckNop(MachineRepresentation::kBit, Type::Boolean(),
               MachineRepresentation::kWord64);
  }
  
  
  TEST(TypeErrors) {
    RepresentationChangerTester r;
  
    // Floats cannot be implicitly converted to/from comparison conditions.
    r.CheckTypeError(MachineRepresentation::kBit, Type::Number(),
                     MachineRepresentation::kFloat32);
    r.CheckTypeError(MachineRepresentation::kBit, Type::Boolean(),
                     MachineRepresentation::kFloat32);
  
    // Word64 is internal and shouldn't be implicitly converted.
    r.CheckTypeError(MachineRepresentation::kWord64, Type::Internal(),
                     MachineRepresentation::kTagged);
    r.CheckTypeError(MachineRepresentation::kTagged, Type::Number(),
                     MachineRepresentation::kWord64);
    r.CheckTypeError(MachineRepresentation::kTagged, Type::Boolean(),
                     MachineRepresentation::kWord64);
    r.CheckTypeError(MachineRepresentation::kWord64, Type::Internal(),
                     MachineRepresentation::kWord32);
    r.CheckTypeError(MachineRepresentation::kWord32, Type::Number(),
                     MachineRepresentation::kWord64);
  }
  
  }  // namespace compiler
  }  // namespace internal
  }  // namespace v8
  