59 lines
2.3 KiB
C++
59 lines
2.3 KiB
C++
/* Copyright 2017 The OpenXLA Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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==============================================================================*/
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#ifndef XLA_SERVICE_HLO_CSE_H_
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#define XLA_SERVICE_HLO_CSE_H_
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#include "xla/hlo/ir/hlo_module.h"
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#include "xla/service/hlo_pass_interface.h"
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namespace xla {
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// A pass which performs common-subexpression elimination. Identical constants
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// and identical instructions with the same operands are commoned. The pass
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// iterates over the instructions in topological order which enables the pass to
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// find arbitrarily large common expressions.
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class HloCSE : public HloModulePass {
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public:
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// If is_layout_sensitive is true, then the simplifier preserves layout during
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// transformation. Otherwise, layout is ignored.
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// If ignore_control_dependencies is true, the pass will ignore control deps
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// when replacing instructions with their equivalents.
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explicit HloCSE(bool is_layout_sensitive,
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bool only_fusion_computations = false,
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bool ignore_control_dependencies = false)
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: is_layout_sensitive_(is_layout_sensitive),
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only_fusion_computations_(only_fusion_computations),
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ignore_control_dependencies_(ignore_control_dependencies) {}
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~HloCSE() override = default;
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absl::string_view name() const override { return "cse"; }
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// Run CSE on the given module. Returns whether the module was changed (common
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// subexpressions were found and eliminated).
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using HloPassInterface::Run;
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StatusOr<bool> Run(
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HloModule* module,
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const absl::flat_hash_set<absl::string_view>& execution_threads) override;
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private:
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const bool is_layout_sensitive_;
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const bool only_fusion_computations_;
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const bool ignore_control_dependencies_;
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};
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} // namespace xla
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#endif // XLA_SERVICE_HLO_CSE_H_
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