| // 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/load-elimination.h" |
| |
| #include "src/compiler/node-properties-inl.h" |
| #include "src/compiler/simplified-operator.h" |
| |
| namespace v8 { |
| namespace internal { |
| namespace compiler { |
| |
| LoadElimination::~LoadElimination() {} |
| |
| |
| Reduction LoadElimination::Reduce(Node* node) { |
| switch (node->opcode()) { |
| case IrOpcode::kLoadField: |
| return ReduceLoadField(node); |
| default: |
| break; |
| } |
| return NoChange(); |
| } |
| |
| |
| Reduction LoadElimination::ReduceLoadField(Node* node) { |
| DCHECK_EQ(IrOpcode::kLoadField, node->opcode()); |
| FieldAccess const access = FieldAccessOf(node->op()); |
| Node* const object = NodeProperties::GetValueInput(node, 0); |
| for (Node* effect = NodeProperties::GetEffectInput(node);; |
| effect = NodeProperties::GetEffectInput(effect)) { |
| switch (effect->opcode()) { |
| case IrOpcode::kLoadField: { |
| if (object == NodeProperties::GetValueInput(effect, 0) && |
| access == FieldAccessOf(effect->op())) { |
| Node* const value = effect; |
| NodeProperties::ReplaceWithValue(node, value); |
| return Replace(value); |
| } |
| break; |
| } |
| case IrOpcode::kStoreField: { |
| if (access == FieldAccessOf(effect->op())) { |
| if (object == NodeProperties::GetValueInput(effect, 0)) { |
| Node* const value = NodeProperties::GetValueInput(effect, 1); |
| NodeProperties::ReplaceWithValue(node, value); |
| return Replace(value); |
| } |
| // TODO(turbofan): Alias analysis to the rescue? |
| return NoChange(); |
| } |
| break; |
| } |
| case IrOpcode::kStoreBuffer: |
| case IrOpcode::kStoreElement: { |
| // These can never interfere with field loads. |
| break; |
| } |
| default: { |
| if (!effect->op()->HasProperty(Operator::kNoWrite) || |
| effect->op()->EffectInputCount() != 1) { |
| return NoChange(); |
| } |
| break; |
| } |
| } |
| } |
| UNREACHABLE(); |
| return NoChange(); |
| } |
| |
| } // namespace compiler |
| } // namespace internal |
| } // namespace v8 |