| // Copyright 2013 the V8 project authors. All rights reserved. |
| // Redistribution and use in source and binary forms, with or without |
| // modification, are permitted provided that the following conditions are |
| // met: |
| // |
| // * Redistributions of source code must retain the above copyright |
| // notice, this list of conditions and the following disclaimer. |
| // * Redistributions in binary form must reproduce the above |
| // copyright notice, this list of conditions and the following |
| // disclaimer in the documentation and/or other materials provided |
| // with the distribution. |
| // * Neither the name of Google Inc. nor the names of its |
| // contributors may be used to endorse or promote products derived |
| // from this software without specific prior written permission. |
| // |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| |
| #include "hydrogen-dehoist.h" |
| |
| namespace v8 { |
| namespace internal { |
| |
| static void DehoistArrayIndex(ArrayInstructionInterface* array_operation) { |
| HValue* index = array_operation->GetKey()->ActualValue(); |
| if (!index->representation().IsSmiOrInteger32()) return; |
| if (!index->IsAdd() && !index->IsSub()) return; |
| |
| HConstant* constant; |
| HValue* subexpression; |
| HBinaryOperation* binary_operation = HBinaryOperation::cast(index); |
| if (binary_operation->left()->IsConstant()) { |
| subexpression = binary_operation->right(); |
| constant = HConstant::cast(binary_operation->left()); |
| } else if (binary_operation->right()->IsConstant()) { |
| subexpression = binary_operation->left(); |
| constant = HConstant::cast(binary_operation->right()); |
| } else { |
| return; |
| } |
| |
| if (!constant->HasInteger32Value()) return; |
| int32_t sign = binary_operation->IsSub() ? -1 : 1; |
| int32_t value = constant->Integer32Value() * sign; |
| // We limit offset values to 30 bits because we want to avoid the risk of |
| // overflows when the offset is added to the object header size. |
| if (value >= 1 << 30 || value < 0) return; |
| array_operation->SetKey(subexpression); |
| if (binary_operation->HasNoUses()) { |
| binary_operation->DeleteAndReplaceWith(NULL); |
| } |
| array_operation->SetIndexOffset(static_cast<uint32_t>(value)); |
| array_operation->SetDehoisted(true); |
| } |
| |
| |
| void HDehoistIndexComputationsPhase::Run() { |
| const ZoneList<HBasicBlock*>* blocks(graph()->blocks()); |
| for (int i = 0; i < blocks->length(); ++i) { |
| for (HInstructionIterator it(blocks->at(i)); !it.Done(); it.Advance()) { |
| HInstruction* instr = it.Current(); |
| if (instr->IsLoadKeyed()) { |
| DehoistArrayIndex(HLoadKeyed::cast(instr)); |
| } else if (instr->IsStoreKeyed()) { |
| DehoistArrayIndex(HStoreKeyed::cast(instr)); |
| } |
| } |
| } |
| } |
| |
| } } // namespace v8::internal |