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_HLO_MODULE_DCE_H_
17 #define TENSORFLOW_COMPILER_XLA_SERVICE_HLO_MODULE_DCE_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 which removes dead code from computations in the module using
26 // HloModule-scoped analysis (HloLivenessAnalysis).
27 //
28 // Sweeps through live instructions which cross computation boundaries (kWhile),
29 // and removes code at dead shape indices.
30 //
31 class HloModuleDCE : public HloModulePass {
32  public:
~HloModuleDCE()33   ~HloModuleDCE() override {}
name()34   absl::string_view name() const override { return "hlo-module-dce"; }
35 
36   // Run the pass on the given module. Returns whether the module was changed
37   // (instructions were removed).
38   StatusOr<bool> Run(HloModule* module) override;
39 };
40 
41 }  // namespace xla
42 
43 #endif  // TENSORFLOW_COMPILER_XLA_SERVICE_HLO_MODULE_DCE_H_
44