1 /* Copyright 2018 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_DESPECIALIZER_H_ 17 #define TENSORFLOW_COMPILER_XLA_SERVICE_DESPECIALIZER_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/service/hlo_pass_pipeline.h" 22 #include "tensorflow/compiler/xla/statusor.h" 23 24 namespace xla { 25 26 // Creates an HloPassPipeline containing multiple HloPasses that can 27 // despecialize an optimized HloModule. This is useful to run an HloModule 28 // optimized for one specific platform on a different platform (undoing platform 29 // specific passes) with matching numerics for comparison. 30 // 31 // Current despecialization passes are HloDescheduler, ControlDepRemover, 32 // Defuser and BFloat16MixedPrecisionRemoval. 33 class Despecializer : public HloModulePass { 34 public: 35 Despecializer(); name()36 absl::string_view name() const override { return "despecializer"; } 37 using HloPassInterface::Run; 38 StatusOr<bool> Run( 39 HloModule* module, 40 const absl::flat_hash_set<absl::string_view>& execution_threads) override; 41 42 private: 43 HloPassPipeline pipeline_; 44 }; 45 46 // Pass which strips control dependencies from all instructions in the module. 47 class ControlDepRemover : public HloModulePass { 48 public: 49 ControlDepRemover() = default; name()50 absl::string_view name() const override { return "control-dep-remover"; } 51 52 using HloPassInterface::Run; Run(HloModule * module,const absl::flat_hash_set<absl::string_view> & execution_threads)53 StatusOr<bool> Run(HloModule* module, 54 const absl::flat_hash_set<absl::string_view>& 55 execution_threads) override { 56 bool changed = false; 57 for (HloComputation* computation : module->computations()) { 58 for (HloInstruction* instruction : computation->instructions()) { 59 changed |= !instruction->control_predecessors().empty(); 60 TF_RETURN_IF_ERROR(instruction->DropAllControlDeps()); 61 } 62 } 63 return changed; 64 } 65 }; 66 67 } // namespace xla 68 69 #endif // TENSORFLOW_COMPILER_XLA_SERVICE_DESPECIALIZER_H_ 70