simplified-operator-reducer.cc 10.7 KB
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// 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/compiler/simplified-operator-reducer.h"

#include "src/compiler/js-graph.h"
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#include "src/compiler/js-heap-broker.h"
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#include "src/compiler/machine-operator.h"
#include "src/compiler/node-matchers.h"
#include "src/compiler/operator-properties.h"
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#include "src/compiler/simplified-operator.h"
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#include "src/compiler/type-cache.h"
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#include "src/numbers/conversions-inl.h"
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namespace v8 {
namespace internal {
namespace compiler {

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namespace {

Decision DecideObjectIsSmi(Node* const input) {
  NumberMatcher m(input);
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  if (m.HasResolvedValue()) {
    return IsSmiDouble(m.ResolvedValue()) ? Decision::kTrue : Decision::kFalse;
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  }
  if (m.IsAllocate()) return Decision::kFalse;
  if (m.IsChangeBitToTagged()) return Decision::kFalse;
  if (m.IsChangeInt31ToTaggedSigned()) return Decision::kTrue;
  if (m.IsHeapConstant()) return Decision::kFalse;
  return Decision::kUnknown;
}

}  // namespace

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SimplifiedOperatorReducer::SimplifiedOperatorReducer(Editor* editor,
                                                     JSGraph* jsgraph,
                                                     JSHeapBroker* broker)
    : AdvancedReducer(editor), jsgraph_(jsgraph), broker_(broker) {}
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SimplifiedOperatorReducer::~SimplifiedOperatorReducer() = default;
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Reduction SimplifiedOperatorReducer::Reduce(Node* node) {
  switch (node->opcode()) {
    case IrOpcode::kBooleanNot: {
      HeapObjectMatcher m(node->InputAt(0));
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      if (m.Is(factory()->true_value())) return ReplaceBoolean(false);
      if (m.Is(factory()->false_value())) return ReplaceBoolean(true);
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      if (m.IsBooleanNot()) return Replace(m.InputAt(0));
      break;
    }
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    case IrOpcode::kChangeBitToTagged: {
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      Int32Matcher m(node->InputAt(0));
      if (m.Is(0)) return Replace(jsgraph()->FalseConstant());
      if (m.Is(1)) return Replace(jsgraph()->TrueConstant());
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      if (m.IsChangeTaggedToBit()) return Replace(m.InputAt(0));
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      break;
    }
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    case IrOpcode::kChangeTaggedToBit: {
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      HeapObjectMatcher m(node->InputAt(0));
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      if (m.HasResolvedValue()) {
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        base::Optional<bool> maybe_result =
            m.Ref(broker()).TryGetBooleanValue();
        if (maybe_result.has_value()) return ReplaceInt32(*maybe_result);
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      }
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      if (m.IsChangeBitToTagged()) return Replace(m.InputAt(0));
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      break;
    }
    case IrOpcode::kChangeFloat64ToTagged: {
      Float64Matcher m(node->InputAt(0));
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      if (m.HasResolvedValue()) return ReplaceNumber(m.ResolvedValue());
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      if (m.IsChangeTaggedToFloat64()) return Replace(m.node()->InputAt(0));
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      break;
    }
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    case IrOpcode::kChangeInt31ToTaggedSigned:
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    case IrOpcode::kChangeInt32ToTagged: {
      Int32Matcher m(node->InputAt(0));
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      if (m.HasResolvedValue()) return ReplaceNumber(m.ResolvedValue());
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      if (m.IsChangeTaggedToInt32() || m.IsChangeTaggedSignedToInt32()) {
        return Replace(m.InputAt(0));
      }
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      break;
    }
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    case IrOpcode::kChangeTaggedToFloat64:
    case IrOpcode::kTruncateTaggedToFloat64: {
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      NumberMatcher m(node->InputAt(0));
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      if (m.HasResolvedValue()) return ReplaceFloat64(m.ResolvedValue());
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      if (m.IsChangeFloat64ToTagged() || m.IsChangeFloat64ToTaggedPointer()) {
        return Replace(m.node()->InputAt(0));
      }
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      if (m.IsChangeInt31ToTaggedSigned() || m.IsChangeInt32ToTagged()) {
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        return Change(node, machine()->ChangeInt32ToFloat64(), m.InputAt(0));
      }
      if (m.IsChangeUint32ToTagged()) {
        return Change(node, machine()->ChangeUint32ToFloat64(), m.InputAt(0));
      }
      break;
    }
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    case IrOpcode::kChangeTaggedSignedToInt32:
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    case IrOpcode::kChangeTaggedToInt32: {
      NumberMatcher m(node->InputAt(0));
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      if (m.HasResolvedValue())
        return ReplaceInt32(DoubleToInt32(m.ResolvedValue()));
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      if (m.IsChangeFloat64ToTagged() || m.IsChangeFloat64ToTaggedPointer()) {
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        return Change(node, machine()->ChangeFloat64ToInt32(), m.InputAt(0));
      }
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      if (m.IsChangeInt31ToTaggedSigned() || m.IsChangeInt32ToTagged()) {
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        return Replace(m.InputAt(0));
      }
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      break;
    }
    case IrOpcode::kChangeTaggedToUint32: {
      NumberMatcher m(node->InputAt(0));
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      if (m.HasResolvedValue())
        return ReplaceUint32(DoubleToUint32(m.ResolvedValue()));
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      if (m.IsChangeFloat64ToTagged() || m.IsChangeFloat64ToTaggedPointer()) {
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        return Change(node, machine()->ChangeFloat64ToUint32(), m.InputAt(0));
      }
      if (m.IsChangeUint32ToTagged()) return Replace(m.InputAt(0));
      break;
    }
    case IrOpcode::kChangeUint32ToTagged: {
      Uint32Matcher m(node->InputAt(0));
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      if (m.HasResolvedValue())
        return ReplaceNumber(FastUI2D(m.ResolvedValue()));
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      break;
    }
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    case IrOpcode::kTruncateTaggedToWord32: {
      NumberMatcher m(node->InputAt(0));
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      if (m.HasResolvedValue())
        return ReplaceInt32(DoubleToInt32(m.ResolvedValue()));
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      if (m.IsChangeInt31ToTaggedSigned() || m.IsChangeInt32ToTagged() ||
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          m.IsChangeUint32ToTagged()) {
        return Replace(m.InputAt(0));
      }
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      if (m.IsChangeFloat64ToTagged() || m.IsChangeFloat64ToTaggedPointer()) {
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        return Change(node, machine()->TruncateFloat64ToWord32(), m.InputAt(0));
      }
      break;
    }
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    case IrOpcode::kCheckedFloat64ToInt32: {
      Float64Matcher m(node->InputAt(0));
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      if (m.HasResolvedValue() && IsInt32Double(m.ResolvedValue())) {
        Node* value =
            jsgraph()->Int32Constant(static_cast<int32_t>(m.ResolvedValue()));
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        ReplaceWithValue(node, value);
        return Replace(value);
      }
      break;
    }
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    case IrOpcode::kCheckedTaggedToArrayIndex:
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    case IrOpcode::kCheckedTaggedToInt32:
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    case IrOpcode::kCheckedTaggedSignedToInt32: {
      NodeMatcher m(node->InputAt(0));
      if (m.IsConvertTaggedHoleToUndefined()) {
        node->ReplaceInput(0, m.InputAt(0));
        return Changed(node);
      }
      break;
    }
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    case IrOpcode::kCheckIf: {
      HeapObjectMatcher m(node->InputAt(0));
      if (m.Is(factory()->true_value())) {
        Node* const effect = NodeProperties::GetEffectInput(node);
        return Replace(effect);
      }
      break;
    }
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    case IrOpcode::kCheckNumber: {
      NodeMatcher m(node->InputAt(0));
      if (m.IsConvertTaggedHoleToUndefined()) {
        node->ReplaceInput(0, m.InputAt(0));
        return Changed(node);
      }
      break;
    }
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    case IrOpcode::kCheckHeapObject: {
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      Node* const input = node->InputAt(0);
      if (DecideObjectIsSmi(input) == Decision::kFalse) {
        ReplaceWithValue(node, input);
        return Replace(input);
      }
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      NodeMatcher m(input);
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      if (m.IsCheckHeapObject()) {
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        ReplaceWithValue(node, input);
        return Replace(input);
      }
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      break;
    }
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    case IrOpcode::kCheckSmi: {
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      Node* const input = node->InputAt(0);
      if (DecideObjectIsSmi(input) == Decision::kTrue) {
        ReplaceWithValue(node, input);
        return Replace(input);
      }
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      NodeMatcher m(input);
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      if (m.IsCheckSmi()) {
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        ReplaceWithValue(node, input);
        return Replace(input);
      } else if (m.IsConvertTaggedHoleToUndefined()) {
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        node->ReplaceInput(0, m.InputAt(0));
        return Changed(node);
      }
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      break;
    }
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    case IrOpcode::kObjectIsSmi: {
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      Node* const input = node->InputAt(0);
      switch (DecideObjectIsSmi(input)) {
        case Decision::kTrue:
          return ReplaceBoolean(true);
        case Decision::kFalse:
          return ReplaceBoolean(false);
        case Decision::kUnknown:
          break;
      }
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      break;
    }
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    case IrOpcode::kNumberAbs: {
      NumberMatcher m(node->InputAt(0));
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      if (m.HasResolvedValue())
        return ReplaceNumber(std::fabs(m.ResolvedValue()));
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      break;
    }
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    case IrOpcode::kReferenceEqual: {
      HeapObjectBinopMatcher m(node);
      if (m.left().node() == m.right().node()) return ReplaceBoolean(true);
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      break;
    }
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    case IrOpcode::kCheckedInt32Add: {
      // (x + a) + b => x + (a + b) where a and b are constants and have the
      // same sign.
      Int32BinopMatcher m(node);
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      if (m.right().HasResolvedValue()) {
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        Node* checked_int32_add = m.left().node();
        if (checked_int32_add->opcode() == IrOpcode::kCheckedInt32Add) {
          Int32BinopMatcher n(checked_int32_add);
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          if (n.right().HasResolvedValue() &&
              (n.right().ResolvedValue() >= 0) ==
                  (m.right().ResolvedValue() >= 0)) {
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            int32_t val;
            bool overflow = base::bits::SignedAddOverflow32(
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                n.right().ResolvedValue(), m.right().ResolvedValue(), &val);
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            if (!overflow) {
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              bool has_no_other_uses = true;
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              for (Edge edge : checked_int32_add->use_edges()) {
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                if (!edge.from()->IsDead() && edge.from() != node) {
                  has_no_other_uses = false;
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                  break;
                }
              }
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              if (has_no_other_uses) {
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                node->ReplaceInput(0, n.left().node());
                node->ReplaceInput(1, jsgraph()->Int32Constant(val));
                RelaxEffectsAndControls(checked_int32_add);
                return Changed(node);
              }
            }
          }
        }
      }
      break;
    }
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    default:
      break;
  }
  return NoChange();
}

Reduction SimplifiedOperatorReducer::Change(Node* node, const Operator* op,
                                            Node* a) {
  DCHECK_EQ(node->InputCount(), OperatorProperties::GetTotalInputCount(op));
  DCHECK_LE(1, node->InputCount());
  node->ReplaceInput(0, a);
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  NodeProperties::ChangeOp(node, op);
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  return Changed(node);
}

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Reduction SimplifiedOperatorReducer::ReplaceBoolean(bool value) {
  return Replace(jsgraph()->BooleanConstant(value));
}
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Reduction SimplifiedOperatorReducer::ReplaceFloat64(double value) {
  return Replace(jsgraph()->Float64Constant(value));
}


Reduction SimplifiedOperatorReducer::ReplaceInt32(int32_t value) {
  return Replace(jsgraph()->Int32Constant(value));
}


Reduction SimplifiedOperatorReducer::ReplaceNumber(double value) {
  return Replace(jsgraph()->Constant(value));
}


Reduction SimplifiedOperatorReducer::ReplaceNumber(int32_t value) {
  return Replace(jsgraph()->Constant(value));
}

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Factory* SimplifiedOperatorReducer::factory() const {
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  return jsgraph()->isolate()->factory();
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}
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Graph* SimplifiedOperatorReducer::graph() const { return jsgraph()->graph(); }

MachineOperatorBuilder* SimplifiedOperatorReducer::machine() const {
  return jsgraph()->machine();
}

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SimplifiedOperatorBuilder* SimplifiedOperatorReducer::simplified() const {
  return jsgraph()->simplified();
}

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}  // namespace compiler
}  // namespace internal
}  // namespace v8