1// Copyright 2014 the V8 project authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#include "src/compiler/simplified-operator-reducer.h"
6
7#include "src/compiler/common-operator.h"
8#include "src/compiler/js-graph.h"
9#include "src/compiler/js-heap-broker.h"
10#include "src/compiler/machine-operator.h"
11#include "src/compiler/node-matchers.h"
12#include "src/compiler/opcodes.h"
13#include "src/compiler/operator-properties.h"
14#include "src/compiler/simplified-operator.h"
15#include "src/compiler/type-cache.h"
16#include "src/numbers/conversions-inl.h"
17
18namespace v8 {
19namespace internal {
20namespace compiler {
21
22namespace {
23
24Decision DecideObjectIsSmi(Node* const input) {
25  NumberMatcher m(input);
26  if (m.HasResolvedValue()) {
27    return IsSmiDouble(m.ResolvedValue()) ? Decision::kTrue : Decision::kFalse;
28  }
29  if (m.IsAllocate()) return Decision::kFalse;
30  if (m.IsChangeBitToTagged()) return Decision::kFalse;
31  if (m.IsChangeInt31ToTaggedSigned()) return Decision::kTrue;
32  if (m.IsHeapConstant()) return Decision::kFalse;
33  return Decision::kUnknown;
34}
35
36}  // namespace
37
38SimplifiedOperatorReducer::SimplifiedOperatorReducer(
39    Editor* editor, JSGraph* jsgraph, JSHeapBroker* broker,
40    BranchSemantics branch_semantics)
41    : AdvancedReducer(editor),
42      jsgraph_(jsgraph),
43      broker_(broker),
44      branch_semantics_(branch_semantics) {}
45
46SimplifiedOperatorReducer::~SimplifiedOperatorReducer() = default;
47
48
49Reduction SimplifiedOperatorReducer::Reduce(Node* node) {
50  switch (node->opcode()) {
51    case IrOpcode::kBooleanNot: {
52      HeapObjectMatcher m(node->InputAt(0));
53      if (m.Is(factory()->true_value())) return ReplaceBoolean(false);
54      if (m.Is(factory()->false_value())) return ReplaceBoolean(true);
55      if (m.IsBooleanNot()) return Replace(m.InputAt(0));
56      break;
57    }
58    case IrOpcode::kChangeBitToTagged: {
59      Int32Matcher m(node->InputAt(0));
60      if (m.Is(0)) return Replace(jsgraph()->FalseConstant());
61      if (m.Is(1)) return Replace(jsgraph()->TrueConstant());
62      if (m.IsChangeTaggedToBit()) return Replace(m.InputAt(0));
63      break;
64    }
65    case IrOpcode::kChangeTaggedToBit: {
66      HeapObjectMatcher m(node->InputAt(0));
67      if (m.HasResolvedValue()) {
68        base::Optional<bool> maybe_result =
69            m.Ref(broker()).TryGetBooleanValue();
70        if (maybe_result.has_value()) return ReplaceInt32(*maybe_result);
71      }
72      if (m.IsChangeBitToTagged()) return Replace(m.InputAt(0));
73      break;
74    }
75    case IrOpcode::kChangeFloat64ToTagged: {
76      Float64Matcher m(node->InputAt(0));
77      if (m.HasResolvedValue()) return ReplaceNumber(m.ResolvedValue());
78      if (m.IsChangeTaggedToFloat64()) return Replace(m.node()->InputAt(0));
79      break;
80    }
81    case IrOpcode::kChangeInt31ToTaggedSigned:
82    case IrOpcode::kChangeInt32ToTagged: {
83      Int32Matcher m(node->InputAt(0));
84      if (m.HasResolvedValue()) return ReplaceNumber(m.ResolvedValue());
85      if (m.IsChangeTaggedSignedToInt32()) {
86        return Replace(m.InputAt(0));
87      }
88      break;
89    }
90    case IrOpcode::kChangeTaggedToFloat64:
91    case IrOpcode::kTruncateTaggedToFloat64: {
92      NumberMatcher m(node->InputAt(0));
93      if (m.HasResolvedValue()) return ReplaceFloat64(m.ResolvedValue());
94      if (m.IsChangeFloat64ToTagged() || m.IsChangeFloat64ToTaggedPointer()) {
95        return Replace(m.node()->InputAt(0));
96      }
97      if (m.IsChangeInt31ToTaggedSigned() || m.IsChangeInt32ToTagged()) {
98        return Change(node, machine()->ChangeInt32ToFloat64(), m.InputAt(0));
99      }
100      if (m.IsChangeUint32ToTagged()) {
101        return Change(node, machine()->ChangeUint32ToFloat64(), m.InputAt(0));
102      }
103      break;
104    }
105    case IrOpcode::kChangeTaggedSignedToInt32:
106    case IrOpcode::kChangeTaggedToInt32: {
107      NumberMatcher m(node->InputAt(0));
108      if (m.HasResolvedValue())
109        return ReplaceInt32(DoubleToInt32(m.ResolvedValue()));
110      if (m.IsChangeFloat64ToTagged() || m.IsChangeFloat64ToTaggedPointer()) {
111        return Change(node, machine()->ChangeFloat64ToInt32(), m.InputAt(0));
112      }
113      if (m.IsChangeInt31ToTaggedSigned() || m.IsChangeInt32ToTagged()) {
114        return Replace(m.InputAt(0));
115      }
116      break;
117    }
118    case IrOpcode::kChangeTaggedToUint32: {
119      NumberMatcher m(node->InputAt(0));
120      if (m.HasResolvedValue())
121        return ReplaceUint32(DoubleToUint32(m.ResolvedValue()));
122      if (m.IsChangeFloat64ToTagged() || m.IsChangeFloat64ToTaggedPointer()) {
123        return Change(node, machine()->ChangeFloat64ToUint32(), m.InputAt(0));
124      }
125      if (m.IsChangeUint32ToTagged()) return Replace(m.InputAt(0));
126      break;
127    }
128    case IrOpcode::kChangeUint32ToTagged: {
129      Uint32Matcher m(node->InputAt(0));
130      if (m.HasResolvedValue())
131        return ReplaceNumber(FastUI2D(m.ResolvedValue()));
132      break;
133    }
134    case IrOpcode::kTruncateTaggedToWord32: {
135      NumberMatcher m(node->InputAt(0));
136      if (m.HasResolvedValue())
137        return ReplaceInt32(DoubleToInt32(m.ResolvedValue()));
138      if (m.IsChangeInt31ToTaggedSigned() || m.IsChangeInt32ToTagged() ||
139          m.IsChangeUint32ToTagged()) {
140        return Replace(m.InputAt(0));
141      }
142      if (m.IsChangeFloat64ToTagged() || m.IsChangeFloat64ToTaggedPointer()) {
143        return Change(node, machine()->TruncateFloat64ToWord32(), m.InputAt(0));
144      }
145      break;
146    }
147    case IrOpcode::kCheckedFloat64ToInt32: {
148      Float64Matcher m(node->InputAt(0));
149      if (m.HasResolvedValue() && IsInt32Double(m.ResolvedValue())) {
150        Node* value =
151            jsgraph()->Int32Constant(static_cast<int32_t>(m.ResolvedValue()));
152        ReplaceWithValue(node, value);
153        return Replace(value);
154      }
155      break;
156    }
157    case IrOpcode::kCheckedTaggedToArrayIndex:
158    case IrOpcode::kCheckedTaggedToInt32:
159    case IrOpcode::kCheckedTaggedSignedToInt32: {
160      NodeMatcher m(node->InputAt(0));
161      if (m.IsConvertTaggedHoleToUndefined()) {
162        node->ReplaceInput(0, m.InputAt(0));
163        return Changed(node);
164      }
165      break;
166    }
167    case IrOpcode::kCheckIf: {
168      HeapObjectMatcher m(node->InputAt(0));
169      if (m.Is(factory()->true_value())) {
170        Node* const effect = NodeProperties::GetEffectInput(node);
171        return Replace(effect);
172      }
173      break;
174    }
175    case IrOpcode::kCheckNumber: {
176      NodeMatcher m(node->InputAt(0));
177      if (m.IsConvertTaggedHoleToUndefined()) {
178        node->ReplaceInput(0, m.InputAt(0));
179        return Changed(node);
180      }
181      break;
182    }
183    case IrOpcode::kCheckHeapObject: {
184      Node* const input = node->InputAt(0);
185      if (DecideObjectIsSmi(input) == Decision::kFalse) {
186        ReplaceWithValue(node, input);
187        return Replace(input);
188      }
189      NodeMatcher m(input);
190      if (m.IsCheckHeapObject()) {
191        ReplaceWithValue(node, input);
192        return Replace(input);
193      }
194      break;
195    }
196    case IrOpcode::kCheckSmi: {
197      Node* const input = node->InputAt(0);
198      if (DecideObjectIsSmi(input) == Decision::kTrue) {
199        ReplaceWithValue(node, input);
200        return Replace(input);
201      }
202      NodeMatcher m(input);
203      if (m.IsCheckSmi()) {
204        ReplaceWithValue(node, input);
205        return Replace(input);
206      } else if (m.IsConvertTaggedHoleToUndefined()) {
207        node->ReplaceInput(0, m.InputAt(0));
208        return Changed(node);
209      }
210      break;
211    }
212    case IrOpcode::kObjectIsSmi: {
213      Node* const input = node->InputAt(0);
214      switch (DecideObjectIsSmi(input)) {
215        case Decision::kTrue:
216          return ReplaceBoolean(true);
217        case Decision::kFalse:
218          return ReplaceBoolean(false);
219        case Decision::kUnknown:
220          break;
221      }
222      break;
223    }
224    case IrOpcode::kNumberAbs: {
225      NumberMatcher m(node->InputAt(0));
226      if (m.HasResolvedValue())
227        return ReplaceNumber(std::fabs(m.ResolvedValue()));
228      break;
229    }
230    case IrOpcode::kReferenceEqual: {
231      HeapObjectBinopMatcher m(node);
232      if (m.left().node() == m.right().node()) return ReplaceBoolean(true);
233      break;
234    }
235    case IrOpcode::kCheckedInt32Add: {
236      // (x + a) + b => x + (a + b) where a and b are constants and have the
237      // same sign.
238      Int32BinopMatcher m(node);
239      if (m.right().HasResolvedValue()) {
240        Node* checked_int32_add = m.left().node();
241        if (checked_int32_add->opcode() == IrOpcode::kCheckedInt32Add) {
242          Int32BinopMatcher n(checked_int32_add);
243          if (n.right().HasResolvedValue() &&
244              (n.right().ResolvedValue() >= 0) ==
245                  (m.right().ResolvedValue() >= 0)) {
246            int32_t val;
247            bool overflow = base::bits::SignedAddOverflow32(
248                n.right().ResolvedValue(), m.right().ResolvedValue(), &val);
249            if (!overflow) {
250              bool has_no_other_uses = true;
251              for (Edge edge : checked_int32_add->use_edges()) {
252                if (!edge.from()->IsDead() && edge.from() != node) {
253                  has_no_other_uses = false;
254                  break;
255                }
256              }
257              if (has_no_other_uses) {
258                node->ReplaceInput(0, n.left().node());
259                node->ReplaceInput(1, jsgraph()->Int32Constant(val));
260                RelaxEffectsAndControls(checked_int32_add);
261                return Changed(node);
262              }
263            }
264          }
265        }
266      }
267      break;
268    }
269    default:
270      break;
271  }
272  return NoChange();
273}
274
275Reduction SimplifiedOperatorReducer::Change(Node* node, const Operator* op,
276                                            Node* a) {
277  DCHECK_EQ(node->InputCount(), OperatorProperties::GetTotalInputCount(op));
278  DCHECK_LE(1, node->InputCount());
279  node->ReplaceInput(0, a);
280  NodeProperties::ChangeOp(node, op);
281  return Changed(node);
282}
283
284Reduction SimplifiedOperatorReducer::ReplaceBoolean(bool value) {
285  if (branch_semantics_ == BranchSemantics::kJS) {
286    return Replace(jsgraph()->BooleanConstant(value));
287  } else {
288    return ReplaceInt32(value);
289  }
290}
291
292Reduction SimplifiedOperatorReducer::ReplaceFloat64(double value) {
293  return Replace(jsgraph()->Float64Constant(value));
294}
295
296
297Reduction SimplifiedOperatorReducer::ReplaceInt32(int32_t value) {
298  return Replace(jsgraph()->Int32Constant(value));
299}
300
301
302Reduction SimplifiedOperatorReducer::ReplaceNumber(double value) {
303  return Replace(jsgraph()->Constant(value));
304}
305
306
307Reduction SimplifiedOperatorReducer::ReplaceNumber(int32_t value) {
308  return Replace(jsgraph()->Constant(value));
309}
310
311Factory* SimplifiedOperatorReducer::factory() const {
312  return jsgraph()->isolate()->factory();
313}
314
315Graph* SimplifiedOperatorReducer::graph() const { return jsgraph()->graph(); }
316
317MachineOperatorBuilder* SimplifiedOperatorReducer::machine() const {
318  return jsgraph()->machine();
319}
320
321SimplifiedOperatorBuilder* SimplifiedOperatorReducer::simplified() const {
322  return jsgraph()->simplified();
323}
324
325}  // namespace compiler
326}  // namespace internal
327}  // namespace v8
328