| OLD | NEW |
| (Empty) |
| 1 // Copyright 2013 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/hydrogen-dehoist.h" | |
| 6 #include "src/base/safe_math.h" | |
| 7 | |
| 8 namespace v8 { | |
| 9 namespace internal { | |
| 10 | |
| 11 static void DehoistArrayIndex(ArrayInstructionInterface* array_operation) { | |
| 12 HValue* index = array_operation->GetKey()->ActualValue(); | |
| 13 if (!index->representation().IsSmiOrInteger32()) return; | |
| 14 if (!index->IsAdd() && !index->IsSub()) return; | |
| 15 | |
| 16 HConstant* constant; | |
| 17 HValue* subexpression; | |
| 18 HBinaryOperation* binary_operation = HBinaryOperation::cast(index); | |
| 19 if (binary_operation->left()->IsConstant() && index->IsAdd()) { | |
| 20 subexpression = binary_operation->right(); | |
| 21 constant = HConstant::cast(binary_operation->left()); | |
| 22 } else if (binary_operation->right()->IsConstant()) { | |
| 23 subexpression = binary_operation->left(); | |
| 24 constant = HConstant::cast(binary_operation->right()); | |
| 25 } else { | |
| 26 return; | |
| 27 } | |
| 28 | |
| 29 if (!constant->HasInteger32Value()) return; | |
| 30 v8::base::internal::CheckedNumeric<int32_t> checked_value = | |
| 31 constant->Integer32Value(); | |
| 32 int32_t sign = binary_operation->IsSub() ? -1 : 1; | |
| 33 checked_value = checked_value * sign; | |
| 34 | |
| 35 // Multiply value by elements size, bailing out on overflow. | |
| 36 int32_t elements_kind_size = | |
| 37 1 << ElementsKindToShiftSize(array_operation->elements_kind()); | |
| 38 checked_value = checked_value * elements_kind_size; | |
| 39 if (!checked_value.IsValid()) return; | |
| 40 int32_t value = checked_value.ValueOrDie(); | |
| 41 if (value < 0) return; | |
| 42 | |
| 43 // Ensure that the array operation can add value to existing base offset | |
| 44 // without overflowing. | |
| 45 if (!array_operation->TryIncreaseBaseOffset(value)) return; | |
| 46 | |
| 47 array_operation->SetKey(subexpression); | |
| 48 if (binary_operation->HasNoUses()) { | |
| 49 binary_operation->DeleteAndReplaceWith(NULL); | |
| 50 } | |
| 51 | |
| 52 array_operation->SetDehoisted(true); | |
| 53 } | |
| 54 | |
| 55 | |
| 56 void HDehoistIndexComputationsPhase::Run() { | |
| 57 const ZoneList<HBasicBlock*>* blocks(graph()->blocks()); | |
| 58 for (int i = 0; i < blocks->length(); ++i) { | |
| 59 for (HInstructionIterator it(blocks->at(i)); !it.Done(); it.Advance()) { | |
| 60 HInstruction* instr = it.Current(); | |
| 61 if (instr->IsLoadKeyed()) { | |
| 62 DehoistArrayIndex(HLoadKeyed::cast(instr)); | |
| 63 } else if (instr->IsStoreKeyed()) { | |
| 64 DehoistArrayIndex(HStoreKeyed::cast(instr)); | |
| 65 } | |
| 66 } | |
| 67 } | |
| 68 } | |
| 69 | |
| 70 } // namespace internal | |
| 71 } // namespace v8 | |
| OLD | NEW |