1 /* Copyright 2019 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 #ifndef TENSORFLOW_COMPILER_XLA_SERVICE_GPU_REDUCTION_DEGENERATE_DIM_REMOVER_H_ 16 #define TENSORFLOW_COMPILER_XLA_SERVICE_GPU_REDUCTION_DEGENERATE_DIM_REMOVER_H_ 17 18 #include "absl/types/optional.h" 19 #include "tensorflow/compiler/xla/service/hlo_instructions.h" 20 #include "tensorflow/compiler/xla/service/hlo_module.h" 21 #include "tensorflow/compiler/xla/service/hlo_pass_interface.h" 22 23 namespace xla { 24 namespace gpu { 25 26 // Enforces the invariant that reduction input and output have no degenerate 27 // (size 1) dimension. Since these dimensions are physically meaningless, they 28 // are removed using bitcasts. 29 // 30 // For example, 31 // 32 // f[1] out = reduce(f[100, 1, 1] input, dimensions={0, 1}) 33 // 34 // becomes: 35 // 36 // 37 // f[100] tmp1 = f[100] bitcast(f[100, 1, 1], input) 38 // f[] tmp2 = reduce(f[100] tmp1, dimensions={0}) 39 // f[1] out = f[] bitcast(tmp2) 40 // 41 class ReductionDegenerateDimRemover : public HloModulePass { 42 public: name()43 absl::string_view name() const override { 44 return "reduction-degenerate-dim-remover"; 45 } 46 47 StatusOr<bool> Run(HloModule* module) override; 48 }; 49 50 } // namespace gpu 51 } // namespace xla 52 53 #endif // TENSORFLOW_COMPILER_XLA_SERVICE_GPU_REDUCTION_DEGENERATE_DIM_REMOVER_H_ 54