1 /* 2 * Copyright (C) 2016 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 /* 18 * This optimization recognizes the common diamond selection pattern and 19 * replaces it with an instance of the HSelect instruction. 20 * 21 * Recognized pattern: 22 * 23 * If [ Condition ] 24 * / \ 25 * false branch true branch 26 * \ / 27 * Phi [FalseValue, TrueValue] 28 * 29 * The pattern will be simplified if `true_branch` and `false_branch` each 30 * contain at most one instruction without any side effects. 31 * 32 * Blocks are merged into one and Select replaces the If and the Phi: 33 * true branch 34 * false branch 35 * Select [FalseValue, TrueValue, Condition] 36 * 37 * Note: In order to recognize no side-effect blocks, this optimization must be 38 * run after the instruction simplifier has removed redundant suspend checks. 39 */ 40 41 #ifndef ART_COMPILER_OPTIMIZING_SELECT_GENERATOR_H_ 42 #define ART_COMPILER_OPTIMIZING_SELECT_GENERATOR_H_ 43 44 #include "optimization.h" 45 46 namespace art { 47 48 class HSelectGenerator : public HOptimization { 49 public: 50 HSelectGenerator(HGraph* graph, OptimizingCompilerStats* stats) 51 : HOptimization(graph, kSelectGeneratorPassName, stats) {} 52 53 void Run() OVERRIDE; 54 55 static constexpr const char* kSelectGeneratorPassName = "select_generator"; 56 57 private: 58 DISALLOW_COPY_AND_ASSIGN(HSelectGenerator); 59 }; 60 61 } // namespace art 62 63 #endif // ART_COMPILER_OPTIMIZING_SELECT_GENERATOR_H_ 64
