1 /* Copyright 2017 The TensorFlow Authors. All Rights Reserved. 2 3 Licensed under the Apache License, Version 2.0 (the "License"); 4 you may not use this file except in compliance with the License. 5 You may obtain a copy of the License at 6 7 http://www.apache.org/licenses/LICENSE-2.0 8 9 Unless required by applicable law or agreed to in writing, software 10 distributed under the License is distributed on an "AS IS" BASIS, 11 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 See the License for the specific language governing permissions and 13 limitations under the License. 14 ==============================================================================*/ 15 16 #ifndef TENSORFLOW_COMPILER_XLA_SERVICE_WHILE_LOOP_SIMPLIFIER_H_ 17 #define TENSORFLOW_COMPILER_XLA_SERVICE_WHILE_LOOP_SIMPLIFIER_H_ 18 19 #include "tensorflow/compiler/xla/service/hlo_module.h" 20 #include "tensorflow/compiler/xla/service/hlo_pass_interface.h" 21 #include "tensorflow/compiler/xla/statusor.h" 22 23 namespace xla { 24 25 // HLO pass that makes the following transformations on while loops: 26 // 27 // - A while loop with static trip count of 0 is deleted. 28 // - A while loops with static trip count of 1 is replaced by its body (sans 29 // loop). 30 // - Elements of a while loop's tuple that the loop doesn't use are removed 31 // from the tuple. 32 // 33 class WhileLoopSimplifier : public HloPassInterface { 34 public: 35 ~WhileLoopSimplifier() override {} 36 tensorflow::StringPiece name() const override { 37 return "simplify-while-loops"; 38 } 39 StatusOr<bool> Run(HloModule* module) override; 40 }; 41 42 } // namespace xla 43 44 #endif // TENSORFLOW_COMPILER_XLA_SERVICE_WHILE_LOOP_SIMPLIFIER_H_ 45
