| /* |
| * Copyright (C) 2014 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #include "instruction_simplifier.h" |
| |
| namespace art { |
| |
| class InstructionSimplifierVisitor : public HGraphVisitor { |
| public: |
| explicit InstructionSimplifierVisitor(HGraph* graph) : HGraphVisitor(graph) {} |
| |
| private: |
| void VisitSuspendCheck(HSuspendCheck* check) OVERRIDE; |
| void VisitEqual(HEqual* equal) OVERRIDE; |
| void VisitArraySet(HArraySet* equal) OVERRIDE; |
| void VisitTypeConversion(HTypeConversion* instruction) OVERRIDE; |
| void VisitNullCheck(HNullCheck* instruction) OVERRIDE; |
| }; |
| |
| void InstructionSimplifier::Run() { |
| InstructionSimplifierVisitor visitor(graph_); |
| visitor.VisitInsertionOrder(); |
| } |
| |
| void InstructionSimplifierVisitor::VisitNullCheck(HNullCheck* null_check) { |
| HInstruction* obj = null_check->InputAt(0); |
| if (!obj->CanBeNull()) { |
| null_check->ReplaceWith(obj); |
| null_check->GetBlock()->RemoveInstruction(null_check); |
| } |
| } |
| |
| void InstructionSimplifierVisitor::VisitSuspendCheck(HSuspendCheck* check) { |
| HBasicBlock* block = check->GetBlock(); |
| // Currently always keep the suspend check at entry. |
| if (block->IsEntryBlock()) return; |
| |
| // Currently always keep suspend checks at loop entry. |
| if (block->IsLoopHeader() && block->GetFirstInstruction() == check) { |
| DCHECK(block->GetLoopInformation()->GetSuspendCheck() == check); |
| return; |
| } |
| |
| // Remove the suspend check that was added at build time for the baseline |
| // compiler. |
| block->RemoveInstruction(check); |
| } |
| |
| void InstructionSimplifierVisitor::VisitEqual(HEqual* equal) { |
| HInstruction* input1 = equal->InputAt(0); |
| HInstruction* input2 = equal->InputAt(1); |
| if (input1->GetType() == Primitive::kPrimBoolean && input2->IsIntConstant()) { |
| if (input2->AsIntConstant()->GetValue() == 1) { |
| // Replace (bool_value == 1) with bool_value |
| equal->ReplaceWith(equal->InputAt(0)); |
| equal->GetBlock()->RemoveInstruction(equal); |
| } else { |
| // We should replace (bool_value == 0) with !bool_value, but we unfortunately |
| // do not have such instruction. |
| DCHECK_EQ(input2->AsIntConstant()->GetValue(), 0); |
| } |
| } |
| } |
| |
| void InstructionSimplifierVisitor::VisitArraySet(HArraySet* instruction) { |
| HInstruction* value = instruction->GetValue(); |
| if (value->GetType() != Primitive::kPrimNot) return; |
| |
| if (value->IsArrayGet()) { |
| if (value->AsArrayGet()->GetArray() == instruction->GetArray()) { |
| // If the code is just swapping elements in the array, no need for a type check. |
| instruction->ClearNeedsTypeCheck(); |
| } |
| } |
| } |
| |
| void InstructionSimplifierVisitor::VisitTypeConversion(HTypeConversion* instruction) { |
| if (instruction->GetResultType() == instruction->GetInputType()) { |
| // Remove the instruction if it's converting to the same type. |
| instruction->ReplaceWith(instruction->GetInput()); |
| instruction->GetBlock()->RemoveInstruction(instruction); |
| } |
| } |
| |
| } // namespace art |