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