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 "src/base/utils/random-number-generator.h"
  #include "src/codegen.h"
  #include "src/compiler/js-graph.h"
  #include "src/compiler/machine-operator-reducer.h"
  #include "src/compiler/operator-properties.h"
  #include "src/compiler/typer.h"
  #include "test/cctest/cctest.h"
  #include "test/cctest/compiler/value-helper.h"
  
  namespace v8 {
  namespace internal {
  namespace compiler {
  
  template <typename T>
  const Operator* NewConstantOperator(CommonOperatorBuilder* common,
                                      volatile T value);
  
  template <>
  const Operator* NewConstantOperator<int32_t>(CommonOperatorBuilder* common,
                                               volatile int32_t value) {
    return common->Int32Constant(value);
  }
  
  template <>
  const Operator* NewConstantOperator<int64_t>(CommonOperatorBuilder* common,
                                               volatile int64_t value) {
    return common->Int64Constant(value);
  }
  
  template <>
  const Operator* NewConstantOperator<double>(CommonOperatorBuilder* common,
                                              volatile double value) {
    return common->Float64Constant(value);
  }
  
  template <>
  const Operator* NewConstantOperator<float>(CommonOperatorBuilder* common,
                                             volatile float value) {
    return common->Float32Constant(value);
  }
  
  template <typename T>
  T ValueOfOperator(const Operator* op);
  
  template <>
  int32_t ValueOfOperator<int32_t>(const Operator* op) {
    CHECK_EQ(IrOpcode::kInt32Constant, op->opcode());
    return OpParameter<int32_t>(op);
  }
  
  template <>
  int64_t ValueOfOperator<int64_t>(const Operator* op) {
    CHECK_EQ(IrOpcode::kInt64Constant, op->opcode());
    return OpParameter<int64_t>(op);
  }
  
  template <>
  float ValueOfOperator<float>(const Operator* op) {
    CHECK_EQ(IrOpcode::kFloat32Constant, op->opcode());
    return OpParameter<float>(op);
  }
  
  template <>
  double ValueOfOperator<double>(const Operator* op) {
    CHECK_EQ(IrOpcode::kFloat64Constant, op->opcode());
    return OpParameter<double>(op);
  }
  
  
  class ReducerTester : public HandleAndZoneScope {
   public:
    explicit ReducerTester(int num_parameters = 0,
                           MachineOperatorBuilder::Flags flags =
                               MachineOperatorBuilder::kAllOptionalOps)
        : isolate(main_isolate()),
          binop(NULL),
          unop(NULL),
          machine(main_zone(), MachineType::PointerRepresentation(), flags),
          common(main_zone()),
          graph(main_zone()),
          javascript(main_zone()),
          typer(isolate, &graph),
          jsgraph(isolate, &graph, &common, &javascript, nullptr, &machine),
          maxuint32(Constant<int32_t>(kMaxUInt32)) {
      Node* s = graph.NewNode(common.Start(num_parameters));
      graph.SetStart(s);
    }
  
    Isolate* isolate;
    const Operator* binop;
    const Operator* unop;
    MachineOperatorBuilder machine;
    CommonOperatorBuilder common;
    Graph graph;
    JSOperatorBuilder javascript;
    Typer typer;
    JSGraph jsgraph;
    Node* maxuint32;
  
    template <typename T>
    Node* Constant(volatile T value) {
      return graph.NewNode(NewConstantOperator<T>(&common, value));
    }
  
    template <typename T>
    const T ValueOf(const Operator* op) {
      return ValueOfOperator<T>(op);
    }
  
    // Check that the reduction of this binop applied to constants {a} and {b}
    // yields the {expect} value.
    template <typename T>
    void CheckFoldBinop(volatile T expect, volatile T a, volatile T b) {
      CheckFoldBinop<T>(expect, Constant<T>(a), Constant<T>(b));
    }
  
    // Check that the reduction of this binop applied to {a} and {b} yields
    // the {expect} value.
    template <typename T>
    void CheckFoldBinop(volatile T expect, Node* a, Node* b) {
      CHECK(binop);
      Node* n = CreateBinopNode(a, b);
      MachineOperatorReducer reducer(&jsgraph);
      Reduction reduction = reducer.Reduce(n);
      CHECK(reduction.Changed());
      CHECK_NE(n, reduction.replacement());
      // Deal with NaNs.
      if (expect == expect) {
        // We do not expect a NaN, check for equality.
        CHECK_EQ(expect, ValueOf<T>(reduction.replacement()->op()));
      } else {
        // Check for NaN.
        T result = ValueOf<T>(reduction.replacement()->op());
        CHECK_NE(result, result);
      }
    }
  
    // Check that the reduction of this binop applied to {a} and {b} yields
    // the {expect} node.
    void CheckBinop(Node* expect, Node* a, Node* b) {
      CHECK(binop);
      Node* n = CreateBinopNode(a, b);
      MachineOperatorReducer reducer(&jsgraph);
      Reduction reduction = reducer.Reduce(n);
      CHECK(reduction.Changed());
      CHECK_EQ(expect, reduction.replacement());
    }
  
    // Check that the reduction of this binop applied to {left} and {right} yields
    // this binop applied to {left_expect} and {right_expect}.
    void CheckFoldBinop(Node* left_expect, Node* right_expect, Node* left,
                        Node* right) {
      CHECK(binop);
      Node* n = CreateBinopNode(left, right);
      MachineOperatorReducer reducer(&jsgraph);
      Reduction reduction = reducer.Reduce(n);
      CHECK(reduction.Changed());
      CHECK_EQ(binop, reduction.replacement()->op());
      CHECK_EQ(left_expect, reduction.replacement()->InputAt(0));
      CHECK_EQ(right_expect, reduction.replacement()->InputAt(1));
    }
  
    // Check that the reduction of this binop applied to {left} and {right} yields
    // the {op_expect} applied to {left_expect} and {right_expect}.
    template <typename T>
    void CheckFoldBinop(volatile T left_expect, const Operator* op_expect,
                        Node* right_expect, Node* left, Node* right) {
      CHECK(binop);
      Node* n = CreateBinopNode(left, right);
      MachineOperatorReducer reducer(&jsgraph);
      Reduction r = reducer.Reduce(n);
      CHECK(r.Changed());
      CHECK_EQ(op_expect->opcode(), r.replacement()->op()->opcode());
      CHECK_EQ(left_expect, ValueOf<T>(r.replacement()->InputAt(0)->op()));
      CHECK_EQ(right_expect, r.replacement()->InputAt(1));
    }
  
    // Check that the reduction of this binop applied to {left} and {right} yields
    // the {op_expect} applied to {left_expect} and {right_expect}.
    template <typename T>
    void CheckFoldBinop(Node* left_expect, const Operator* op_expect,
                        volatile T right_expect, Node* left, Node* right) {
      CHECK(binop);
      Node* n = CreateBinopNode(left, right);
      MachineOperatorReducer reducer(&jsgraph);
      Reduction r = reducer.Reduce(n);
      CHECK(r.Changed());
      CHECK_EQ(op_expect->opcode(), r.replacement()->op()->opcode());
      CHECK_EQ(OperatorProperties::GetTotalInputCount(op_expect),
               r.replacement()->InputCount());
      CHECK_EQ(left_expect, r.replacement()->InputAt(0));
      CHECK_EQ(right_expect, ValueOf<T>(r.replacement()->InputAt(1)->op()));
    }
  
    // Check that if the given constant appears on the left, the reducer will
    // swap it to be on the right.
    template <typename T>
    void CheckPutConstantOnRight(volatile T constant) {
      // TODO(titzer): CHECK(binop->HasProperty(Operator::kCommutative));
      Node* p = Parameter();
      Node* k = Constant<T>(constant);
      {
        Node* n = CreateBinopNode(k, p);
        MachineOperatorReducer reducer(&jsgraph);
        Reduction reduction = reducer.Reduce(n);
        CHECK(!reduction.Changed() || reduction.replacement() == n);
        CHECK_EQ(p, n->InputAt(0));
        CHECK_EQ(k, n->InputAt(1));
      }
      {
        Node* n = CreateBinopNode(p, k);
        MachineOperatorReducer reducer(&jsgraph);
        Reduction reduction = reducer.Reduce(n);
        CHECK(!reduction.Changed());
        CHECK_EQ(p, n->InputAt(0));
        CHECK_EQ(k, n->InputAt(1));
      }
    }
  
    // Check that if the given constant appears on the left, the reducer will
    // *NOT* swap it to be on the right.
    template <typename T>
    void CheckDontPutConstantOnRight(volatile T constant) {
      CHECK(!binop->HasProperty(Operator::kCommutative));
      Node* p = Parameter();
      Node* k = Constant<T>(constant);
      Node* n = CreateBinopNode(k, p);
      MachineOperatorReducer reducer(&jsgraph);
      Reduction reduction = reducer.Reduce(n);
      CHECK(!reduction.Changed());
      CHECK_EQ(k, n->InputAt(0));
      CHECK_EQ(p, n->InputAt(1));
    }
  
    Node* Parameter(int32_t index = 0) {
      return graph.NewNode(common.Parameter(index), graph.start());
    }
  
   private:
    Node* CreateBinopNode(Node* left, Node* right) {
      if (binop->ControlInputCount() > 0) {
        return graph.NewNode(binop, left, right, graph.start());
      } else {
        return graph.NewNode(binop, left, right);
      }
    }
  };
  
  
  TEST(ReduceWord32And) {
    ReducerTester R;
    R.binop = R.machine.Word32And();
  
    FOR_INT32_INPUTS(pl) {
      FOR_INT32_INPUTS(pr) {
        int32_t x = *pl, y = *pr;
        R.CheckFoldBinop<int32_t>(x & y, x, y);
      }
    }
  
    R.CheckPutConstantOnRight(33);
    R.CheckPutConstantOnRight(44000);
  
    Node* x = R.Parameter();
    Node* zero = R.Constant<int32_t>(0);
    Node* minus_1 = R.Constant<int32_t>(-1);
  
    R.CheckBinop(zero, x, zero);  // x  & 0  => 0
    R.CheckBinop(zero, zero, x);  // 0  & x  => 0
    R.CheckBinop(x, x, minus_1);  // x  & -1 => 0
    R.CheckBinop(x, minus_1, x);  // -1 & x  => 0
    R.CheckBinop(x, x, x);        // x  & x  => x
  }
  
  
  TEST(ReduceWord32Or) {
    ReducerTester R;
    R.binop = R.machine.Word32Or();
  
    FOR_INT32_INPUTS(pl) {
      FOR_INT32_INPUTS(pr) {
        int32_t x = *pl, y = *pr;
        R.CheckFoldBinop<int32_t>(x | y, x, y);
      }
    }
  
    R.CheckPutConstantOnRight(36);
    R.CheckPutConstantOnRight(44001);
  
    Node* x = R.Parameter();
    Node* zero = R.Constant<int32_t>(0);
    Node* minus_1 = R.Constant<int32_t>(-1);
  
    R.CheckBinop(x, x, zero);           // x  & 0  => x
    R.CheckBinop(x, zero, x);           // 0  & x  => x
    R.CheckBinop(minus_1, x, minus_1);  // x  & -1 => -1
    R.CheckBinop(minus_1, minus_1, x);  // -1 & x  => -1
    R.CheckBinop(x, x, x);              // x  & x  => x
  }
  
  
  TEST(ReduceWord32Xor) {
    ReducerTester R;
    R.binop = R.machine.Word32Xor();
  
    FOR_INT32_INPUTS(pl) {
      FOR_INT32_INPUTS(pr) {
        int32_t x = *pl, y = *pr;
        R.CheckFoldBinop<int32_t>(x ^ y, x, y);
      }
    }
  
    R.CheckPutConstantOnRight(39);
    R.CheckPutConstantOnRight(4403);
  
    Node* x = R.Parameter();
    Node* zero = R.Constant<int32_t>(0);
  
    R.CheckBinop(x, x, zero);            // x ^ 0  => x
    R.CheckBinop(x, zero, x);            // 0 ^ x  => x
    R.CheckFoldBinop<int32_t>(0, x, x);  // x ^ x  => 0
  }
  
  
  TEST(ReduceWord32Shl) {
    ReducerTester R;
    R.binop = R.machine.Word32Shl();
  
    // TODO(titzer): out of range shifts
    FOR_INT32_INPUTS(i) {
      for (int y = 0; y < 32; y++) {
        int32_t x = *i;
        R.CheckFoldBinop<int32_t>(x << y, x, y);
      }
    }
  
    R.CheckDontPutConstantOnRight(44);
  
    Node* x = R.Parameter();
    Node* zero = R.Constant<int32_t>(0);
  
    R.CheckBinop(x, x, zero);  // x << 0  => x
  }
  
  TEST(ReduceWord64Shl) {
    ReducerTester R;
    R.binop = R.machine.Word64Shl();
  
    FOR_INT64_INPUTS(i) {
      for (int64_t y = 0; y < 64; y++) {
        int64_t x = *i;
        R.CheckFoldBinop<int64_t>(x << y, x, y);
      }
    }
  
    R.CheckDontPutConstantOnRight(44);
  
    Node* x = R.Parameter();
    Node* zero = R.Constant<int64_t>(0);
  
    R.CheckBinop(x, x, zero);  // x << 0  => x
  }
  
  TEST(ReduceWord32Shr) {
    ReducerTester R;
    R.binop = R.machine.Word32Shr();
  
    // TODO(titzer): test out of range shifts
    FOR_UINT32_INPUTS(i) {
      for (uint32_t y = 0; y < 32; y++) {
        uint32_t x = *i;
        R.CheckFoldBinop<int32_t>(x >> y, x, y);
      }
    }
  
    R.CheckDontPutConstantOnRight(44);
  
    Node* x = R.Parameter();
    Node* zero = R.Constant<int32_t>(0);
  
    R.CheckBinop(x, x, zero);  // x >>> 0  => x
  }
  
  TEST(ReduceWord64Shr) {
    ReducerTester R;
    R.binop = R.machine.Word64Shr();
  
    FOR_UINT64_INPUTS(i) {
      for (uint64_t y = 0; y < 64; y++) {
        uint64_t x = *i;
        R.CheckFoldBinop<int64_t>(x >> y, x, y);
      }
    }
  
    R.CheckDontPutConstantOnRight(44);
  
    Node* x = R.Parameter();
    Node* zero = R.Constant<int64_t>(0);
  
    R.CheckBinop(x, x, zero);  // x >>> 0  => x
  }
  
  TEST(ReduceWord32Sar) {
    ReducerTester R;
    R.binop = R.machine.Word32Sar();
  
    // TODO(titzer): test out of range shifts
    FOR_INT32_INPUTS(i) {
      for (int32_t y = 0; y < 32; y++) {
        int32_t x = *i;
        R.CheckFoldBinop<int32_t>(x >> y, x, y);
      }
    }
  
    R.CheckDontPutConstantOnRight(44);
  
    Node* x = R.Parameter();
    Node* zero = R.Constant<int32_t>(0);
  
    R.CheckBinop(x, x, zero);  // x >> 0  => x
  }
  
  TEST(ReduceWord64Sar) {
    ReducerTester R;
    R.binop = R.machine.Word64Sar();
  
    FOR_INT64_INPUTS(i) {
      for (int64_t y = 0; y < 64; y++) {
        int64_t x = *i;
        R.CheckFoldBinop<int64_t>(x >> y, x, y);
      }
    }
  
    R.CheckDontPutConstantOnRight(44);
  
    Node* x = R.Parameter();
    Node* zero = R.Constant<int64_t>(0);
  
    R.CheckBinop(x, x, zero);  // x >> 0  => x
  }
  
  static void CheckJsShift(ReducerTester* R) {
    CHECK(R->machine.Word32ShiftIsSafe());
  
    Node* x = R->Parameter(0);
    Node* y = R->Parameter(1);
    Node* thirty_one = R->Constant<int32_t>(0x1f);
    Node* y_and_thirty_one =
        R->graph.NewNode(R->machine.Word32And(), y, thirty_one);
  
    // If the underlying machine shift instructions 'and' their right operand
    // with 0x1f then:  x << (y & 0x1f) => x << y
    R->CheckFoldBinop(x, y, x, y_and_thirty_one);
  }
  
  
  TEST(ReduceJsShifts) {
    ReducerTester R(0, MachineOperatorBuilder::kWord32ShiftIsSafe);
  
    R.binop = R.machine.Word32Shl();
    CheckJsShift(&R);
  
    R.binop = R.machine.Word32Shr();
    CheckJsShift(&R);
  
    R.binop = R.machine.Word32Sar();
    CheckJsShift(&R);
  }
  
  
  TEST(Word32Equal) {
    ReducerTester R;
    R.binop = R.machine.Word32Equal();
  
    FOR_INT32_INPUTS(pl) {
      FOR_INT32_INPUTS(pr) {
        int32_t x = *pl, y = *pr;
        R.CheckFoldBinop<int32_t>(x == y ? 1 : 0, x, y);
      }
    }
  
    R.CheckPutConstantOnRight(48);
    R.CheckPutConstantOnRight(-48);
  
    Node* x = R.Parameter(0);
    Node* y = R.Parameter(1);
    Node* zero = R.Constant<int32_t>(0);
    Node* sub = R.graph.NewNode(R.machine.Int32Sub(), x, y);
  
    R.CheckFoldBinop<int32_t>(1, x, x);  // x == x  => 1
    R.CheckFoldBinop(x, y, sub, zero);   // x - y == 0  => x == y
    R.CheckFoldBinop(x, y, zero, sub);   // 0 == x - y  => x == y
  }
  
  
  TEST(ReduceInt32Add) {
    ReducerTester R;
    R.binop = R.machine.Int32Add();
  
    FOR_INT32_INPUTS(pl) {
      FOR_INT32_INPUTS(pr) {
        int32_t x = *pl, y = *pr;
        R.CheckFoldBinop<int32_t>(x + y, x, y);  // TODO(titzer): signed overflow
      }
    }
  
    R.CheckPutConstantOnRight(41);
    R.CheckPutConstantOnRight(4407);
  
    Node* x = R.Parameter();
    Node* zero = R.Constant<int32_t>(0);
  
    R.CheckBinop(x, x, zero);  // x + 0  => x
    R.CheckBinop(x, zero, x);  // 0 + x  => x
  }
  
  TEST(ReduceInt64Add) {
    ReducerTester R;
    R.binop = R.machine.Int64Add();
  
    FOR_INT64_INPUTS(pl) {
      FOR_INT64_INPUTS(pr) {
        int64_t x = *pl, y = *pr;
        R.CheckFoldBinop<int64_t>(x + y, x, y);
      }
    }
  
    R.CheckPutConstantOnRight(41);
  
    Node* x = R.Parameter();
    Node* zero = R.Constant<int64_t>(0);
    R.CheckBinop(x, x, zero);  // x + 0 => x
    R.CheckBinop(x, zero, x);  // 0 + x => x
  }
  
  TEST(ReduceInt32Sub) {
    ReducerTester R;
    R.binop = R.machine.Int32Sub();
  
    FOR_INT32_INPUTS(pl) {
      FOR_INT32_INPUTS(pr) {
        int32_t x = *pl, y = *pr;
        R.CheckFoldBinop<int32_t>(x - y, x, y);
      }
    }
  
    R.CheckDontPutConstantOnRight(412);
  
    Node* x = R.Parameter();
    Node* zero = R.Constant<int32_t>(0);
  
    R.CheckBinop(x, x, zero);  // x - 0  => x
  }
  
  TEST(ReduceInt64Sub) {
    ReducerTester R;
    R.binop = R.machine.Int64Sub();
  
    FOR_INT64_INPUTS(pl) {
      FOR_INT64_INPUTS(pr) {
        int64_t x = *pl, y = *pr;
        R.CheckFoldBinop<int64_t>(x - y, x, y);
      }
    }
  
    R.CheckDontPutConstantOnRight(42);
  
    Node* x = R.Parameter();
    Node* zero = R.Constant<int64_t>(0);
  
    R.CheckBinop(x, x, zero);            // x - 0 => x
    R.CheckFoldBinop<int64_t>(0, x, x);  // x - x => 0
  
    Node* k = R.Constant<int64_t>(6);
  
    R.CheckFoldBinop<int64_t>(x, R.machine.Int64Add(), -6, x,
                              k);  // x - K => x + -K
  }
  
  TEST(ReduceInt32Mul) {
    ReducerTester R;
    R.binop = R.machine.Int32Mul();
  
    FOR_INT32_INPUTS(pl) {
      FOR_INT32_INPUTS(pr) {
        int32_t x = *pl, y = *pr;
        R.CheckFoldBinop<int32_t>(x * y, x, y);  // TODO(titzer): signed overflow
      }
    }
  
    R.CheckPutConstantOnRight(4111);
    R.CheckPutConstantOnRight(-4407);
  
    Node* x = R.Parameter();
    Node* zero = R.Constant<int32_t>(0);
    Node* one = R.Constant<int32_t>(1);
    Node* minus_one = R.Constant<int32_t>(-1);
  
    R.CheckBinop(zero, x, zero);  // x * 0  => 0
    R.CheckBinop(zero, zero, x);  // 0 * x  => 0
    R.CheckBinop(x, x, one);      // x * 1  => x
    R.CheckBinop(x, one, x);      // 1 * x  => x
    R.CheckFoldBinop<int32_t>(0, R.machine.Int32Sub(), x, minus_one,
                              x);  // -1 * x  => 0 - x
    R.CheckFoldBinop<int32_t>(0, R.machine.Int32Sub(), x, x,
                              minus_one);  // x * -1  => 0 - x
  
    for (int32_t n = 1; n < 31; ++n) {
      Node* multiplier = R.Constant<int32_t>(1 << n);
      R.CheckFoldBinop<int32_t>(x, R.machine.Word32Shl(), n, x,
                                multiplier);  // x * 2^n => x << n
      R.CheckFoldBinop<int32_t>(x, R.machine.Word32Shl(), n, multiplier,
                                x);  // 2^n * x => x << n
    }
  }
  
  
  TEST(ReduceInt32Div) {
    ReducerTester R;
    R.binop = R.machine.Int32Div();
  
    FOR_INT32_INPUTS(pl) {
      FOR_INT32_INPUTS(pr) {
        int32_t x = *pl, y = *pr;
        if (y == 0) continue;              // TODO(titzer): test / 0
        int32_t r = y == -1 ? -x : x / y;  // INT_MIN / -1 may explode in C
        R.CheckFoldBinop<int32_t>(r, x, y);
      }
    }
  
    R.CheckDontPutConstantOnRight(41111);
    R.CheckDontPutConstantOnRight(-44071);
  
    Node* x = R.Parameter();
    Node* one = R.Constant<int32_t>(1);
    Node* minus_one = R.Constant<int32_t>(-1);
  
    R.CheckBinop(x, x, one);  // x / 1  => x
    // TODO(titzer):                          // 0 / x  => 0 if x != 0
    // TODO(titzer):                          // x / 2^n => x >> n and round
    R.CheckFoldBinop<int32_t>(0, R.machine.Int32Sub(), x, x,
                              minus_one);  // x / -1  => 0 - x
  }
  
  
  TEST(ReduceUint32Div) {
    ReducerTester R;
    R.binop = R.machine.Uint32Div();
  
    FOR_UINT32_INPUTS(pl) {
      FOR_UINT32_INPUTS(pr) {
        uint32_t x = *pl, y = *pr;
        if (y == 0) continue;  // TODO(titzer): test / 0
        R.CheckFoldBinop<int32_t>(x / y, x, y);
      }
    }
  
    R.CheckDontPutConstantOnRight(41311);
    R.CheckDontPutConstantOnRight(-44371);
  
    Node* x = R.Parameter();
    Node* one = R.Constant<int32_t>(1);
  
    R.CheckBinop(x, x, one);  // x / 1  => x
    // TODO(titzer):                            // 0 / x  => 0 if x != 0
  
    for (uint32_t n = 1; n < 32; ++n) {
      Node* divisor = R.Constant<int32_t>(1u << n);
      R.CheckFoldBinop<int32_t>(x, R.machine.Word32Shr(), n, x,
                                divisor);  // x / 2^n => x >> n
    }
  }
  
  
  TEST(ReduceInt32Mod) {
    ReducerTester R;
    R.binop = R.machine.Int32Mod();
  
    FOR_INT32_INPUTS(pl) {
      FOR_INT32_INPUTS(pr) {
        int32_t x = *pl, y = *pr;
        if (y == 0) continue;             // TODO(titzer): test % 0
        int32_t r = y == -1 ? 0 : x % y;  // INT_MIN % -1 may explode in C
        R.CheckFoldBinop<int32_t>(r, x, y);
      }
    }
  
    R.CheckDontPutConstantOnRight(413);
    R.CheckDontPutConstantOnRight(-4401);
  
    Node* x = R.Parameter();
    Node* one = R.Constant<int32_t>(1);
  
    R.CheckFoldBinop<int32_t>(0, x, one);  // x % 1  => 0
    // TODO(titzer):                       // x % 2^n => x & 2^n-1 and round
  }
  
  
  TEST(ReduceUint32Mod) {
    ReducerTester R;
    R.binop = R.machine.Uint32Mod();
  
    FOR_INT32_INPUTS(pl) {
      FOR_INT32_INPUTS(pr) {
        uint32_t x = *pl, y = *pr;
        if (y == 0) continue;  // TODO(titzer): test x % 0
        R.CheckFoldBinop<int32_t>(x % y, x, y);
      }
    }
  
    R.CheckDontPutConstantOnRight(417);
    R.CheckDontPutConstantOnRight(-4371);
  
    Node* x = R.Parameter();
    Node* one = R.Constant<int32_t>(1);
  
    R.CheckFoldBinop<int32_t>(0, x, one);  // x % 1  => 0
  
    for (uint32_t n = 1; n < 32; ++n) {
      Node* divisor = R.Constant<int32_t>(1u << n);
      R.CheckFoldBinop<int32_t>(x, R.machine.Word32And(), (1u << n) - 1, x,
                                divisor);  // x % 2^n => x & 2^n-1
    }
  }
  
  
  TEST(ReduceInt32LessThan) {
    ReducerTester R;
    R.binop = R.machine.Int32LessThan();
  
    FOR_INT32_INPUTS(pl) {
      FOR_INT32_INPUTS(pr) {
        int32_t x = *pl, y = *pr;
        R.CheckFoldBinop<int32_t>(x < y ? 1 : 0, x, y);
      }
    }
  
    R.CheckDontPutConstantOnRight(41399);
    R.CheckDontPutConstantOnRight(-440197);
  
    Node* x = R.Parameter(0);
  
    R.CheckFoldBinop<int32_t>(0, x, x);  // x < x  => 0
  }
  
  
  TEST(ReduceInt32LessThanOrEqual) {
    ReducerTester R;
    R.binop = R.machine.Int32LessThanOrEqual();
  
    FOR_INT32_INPUTS(pl) {
      FOR_INT32_INPUTS(pr) {
        int32_t x = *pl, y = *pr;
        R.CheckFoldBinop<int32_t>(x <= y ? 1 : 0, x, y);
      }
    }
  
    FOR_INT32_INPUTS(i) { R.CheckDontPutConstantOnRight<int32_t>(*i); }
  
    Node* x = R.Parameter(0);
  
    R.CheckFoldBinop<int32_t>(1, x, x);  // x <= x => 1
  }
  
  
  TEST(ReduceUint32LessThan) {
    ReducerTester R;
    R.binop = R.machine.Uint32LessThan();
  
    FOR_UINT32_INPUTS(pl) {
      FOR_UINT32_INPUTS(pr) {
        uint32_t x = *pl, y = *pr;
        R.CheckFoldBinop<int32_t>(x < y ? 1 : 0, x, y);
      }
    }
  
    R.CheckDontPutConstantOnRight(41399);
    R.CheckDontPutConstantOnRight(-440197);
  
    Node* x = R.Parameter();
    Node* max = R.maxuint32;
    Node* zero = R.Constant<int32_t>(0);
  
    R.CheckFoldBinop<int32_t>(0, max, x);   // M < x  => 0
    R.CheckFoldBinop<int32_t>(0, x, zero);  // x < 0  => 0
    R.CheckFoldBinop<int32_t>(0, x, x);     // x < x  => 0
  }
  
  
  TEST(ReduceUint32LessThanOrEqual) {
    ReducerTester R;
    R.binop = R.machine.Uint32LessThanOrEqual();
  
    FOR_UINT32_INPUTS(pl) {
      FOR_UINT32_INPUTS(pr) {
        uint32_t x = *pl, y = *pr;
        R.CheckFoldBinop<int32_t>(x <= y ? 1 : 0, x, y);
      }
    }
  
    R.CheckDontPutConstantOnRight(41399);
    R.CheckDontPutConstantOnRight(-440197);
  
    Node* x = R.Parameter();
    Node* max = R.maxuint32;
    Node* zero = R.Constant<int32_t>(0);
  
    R.CheckFoldBinop<int32_t>(1, x, max);   // x <= M  => 1
    R.CheckFoldBinop<int32_t>(1, zero, x);  // 0 <= x  => 1
    R.CheckFoldBinop<int32_t>(1, x, x);     // x <= x  => 1
  }
  
  
  TEST(ReduceLoadStore) {
    ReducerTester R;
  
    Node* base = R.Constant<int32_t>(11);
    Node* index = R.Constant<int32_t>(4);
    Node* load = R.graph.NewNode(R.machine.Load(MachineType::Int32()), base,
                                 index, R.graph.start(), R.graph.start());
  
    {
      MachineOperatorReducer reducer(&R.jsgraph);
      Reduction reduction = reducer.Reduce(load);
      CHECK(!reduction.Changed());  // loads should not be reduced.
    }
  
    {
      Node* store =
          R.graph.NewNode(R.machine.Store(StoreRepresentation(
                              MachineRepresentation::kWord32, kNoWriteBarrier)),
                          base, index, load, load, R.graph.start());
      MachineOperatorReducer reducer(&R.jsgraph);
      Reduction reduction = reducer.Reduce(store);
      CHECK(!reduction.Changed());  // stores should not be reduced.
    }
  }
  
  TEST(ReduceFloat32Sub) {
    ReducerTester R;
    R.binop = R.machine.Float32Sub();
  
    FOR_FLOAT32_INPUTS(pl) {
      FOR_FLOAT32_INPUTS(pr) {
        float x = *pl, y = *pr;
        R.CheckFoldBinop<float>(x - y, x, y);
      }
    }
  
    Node* x = R.Parameter();
    Node* zero = R.Constant<float>(0.0);
    Node* nan = R.Constant<float>(std::numeric_limits<float>::quiet_NaN());
  
    R.CheckBinop(x, x, zero);   // x - 0 => x
    R.CheckBinop(nan, nan, x);  // nan - x  => nan
    R.CheckBinop(nan, x, nan);  // x - nan => nan
  }
  
  TEST(ReduceFloat64Sub) {
    ReducerTester R;
    R.binop = R.machine.Float64Sub();
  
    FOR_FLOAT64_INPUTS(pl) {
      FOR_FLOAT64_INPUTS(pr) {
        double x = *pl, y = *pr;
        R.CheckFoldBinop<double>(x - y, x, y);
      }
    }
  
    Node* x = R.Parameter();
    Node* zero = R.Constant<double>(0.0);
    Node* nan = R.Constant<double>(std::numeric_limits<double>::quiet_NaN());
  
    R.CheckBinop(x, x, zero);   // x - 0 => x
    R.CheckBinop(nan, nan, x);  // nan - x  => nan
    R.CheckBinop(nan, x, nan);  // x - nan => nan
  }
  
  // TODO(titzer): test MachineOperatorReducer for Word64And
  // TODO(titzer): test MachineOperatorReducer for Word64Or
  // TODO(titzer): test MachineOperatorReducer for Word64Xor
  // TODO(titzer): test MachineOperatorReducer for Word64Equal
  // TODO(titzer): test MachineOperatorReducer for Word64Not
  // TODO(titzer): test MachineOperatorReducer for Int64Mul
  // TODO(titzer): test MachineOperatorReducer for Int64UMul
  // TODO(titzer): test MachineOperatorReducer for Int64Div
  // TODO(titzer): test MachineOperatorReducer for Uint64Div
  // TODO(titzer): test MachineOperatorReducer for Int64Mod
  // TODO(titzer): test MachineOperatorReducer for Uint64Mod
  // TODO(titzer): test MachineOperatorReducer for Int64Neg
  // TODO(titzer): test MachineOperatorReducer for ChangeInt32ToFloat64
  // TODO(titzer): test MachineOperatorReducer for ChangeFloat64ToInt32
  // TODO(titzer): test MachineOperatorReducer for Float64Compare
  // TODO(titzer): test MachineOperatorReducer for Float64Add
  // TODO(titzer): test MachineOperatorReducer for Float64Sub
  // TODO(titzer): test MachineOperatorReducer for Float64Mul
  // TODO(titzer): test MachineOperatorReducer for Float64Div
  // TODO(titzer): test MachineOperatorReducer for Float64Mod
  
  }  // namespace compiler
  }  // namespace internal
  }  // namespace v8
  