instruction_simplifier.cc revision 1cc5f251df558b0e22cea5000626365eb644c727 
1/*
2 * Copyright (C) 2014 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include "instruction_simplifier.h"
18
19namespace art {
20
21void InstructionSimplifier::Run() {
22  VisitInsertionOrder();
23}
24
25void InstructionSimplifier::VisitSuspendCheck(HSuspendCheck* check) {
26  HBasicBlock* block = check->GetBlock();
27  // Currently always keep the suspend check at entry.
28  if (block->IsEntryBlock()) return;
29
30  // Currently always keep suspend checks at loop entry.
31  if (block->IsLoopHeader() && block->GetFirstInstruction() == check) {
32    DCHECK(block->GetLoopInformation()->GetSuspendCheck() == check);
33    return;
34  }
35
36  // Remove the suspend check that was added at build time for the baseline
37  // compiler.
38  block->RemoveInstruction(check);
39}
40
41void InstructionSimplifier::VisitEqual(HEqual* equal) {
42  HInstruction* input1 = equal->InputAt(0);
43  HInstruction* input2 = equal->InputAt(1);
44  if (input1->GetType() == Primitive::kPrimBoolean && input2->IsIntConstant()) {
45    if (input2->AsIntConstant()->GetValue() == 1) {
46      // Replace (bool_value == 1) with bool_value
47      equal->ReplaceWith(equal->InputAt(0));
48      equal->GetBlock()->RemoveInstruction(equal);
49    } else {
50      // Replace (bool_value == 0) with !bool_value
51      DCHECK_EQ(input2->AsIntConstant()->GetValue(), 0);
52      equal->GetBlock()->ReplaceAndRemoveInstructionWith(
53          equal, new (GetGraph()->GetArena()) HNot(Primitive::kPrimBoolean, input1));
54    }
55  }
56}
57
58}  // namespace art
59