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 #ifndef ART_COMPILER_OPTIMIZING_CONSTANT_FOLDING_H_
18 #define ART_COMPILER_OPTIMIZING_CONSTANT_FOLDING_H_
19 
20 #include "base/macros.h"
21 #include "nodes.h"
22 #include "optimization.h"
23 #include "optimizing/optimizing_compiler_stats.h"
24 
25 namespace art HIDDEN {
26 
27 /**
28  * Optimization pass performing a simple constant-expression
29  * evaluation on the SSA form.
30  *
31  * Note that graph simplifications producing a constant should be
32  * implemented in art::HConstantFolding, while graph simplifications
33  * not producing constants should be implemented in
34  * art::InstructionSimplifier.  (This convention is a choice that was
35  * made during the development of these parts of the compiler and is
36  * not bound by any technical requirement.)
37  *
38  * This class is named art::HConstantFolding to avoid name
39  * clashes with the art::ConstantPropagation class defined in
40  * compiler/dex/post_opt_passes.h.
41  */
42 class HConstantFolding : public HOptimization {
43  public:
44   HConstantFolding(HGraph* graph,
45                    OptimizingCompilerStats* stats = nullptr,
46                    const char* name = kConstantFoldingPassName)
HOptimization(graph,name,stats)47       : HOptimization(graph, name, stats) {}
48 
49   bool Run() override;
50 
51   static constexpr const char* kConstantFoldingPassName = "constant_folding";
52 
53  private:
54   DISALLOW_COPY_AND_ASSIGN(HConstantFolding);
55 };
56 
57 }  // namespace art
58 
59 #endif  // ART_COMPILER_OPTIMIZING_CONSTANT_FOLDING_H_
60