87 lines
2.9 KiB
C
87 lines
2.9 KiB
C
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/* Copyright 2020 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_TOPK_REWRITER_H_
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#define XLA_SERVICE_TOPK_REWRITER_H_
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#include <functional>
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#include <memory>
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#include <optional>
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#include <utility>
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#include "xla/hlo/ir/dfs_hlo_visitor_with_default.h"
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#include "xla/hlo/ir/hlo_instruction.h"
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#include "xla/hlo/ir/hlo_instructions.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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// This pass pattern-matches soups of HLOs executing a TopK operation and
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// replaces them with a TopK CustomCall when the given values are supported by
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// the CustomCall and it is more efficient to use that implementation.
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class TopkRewriter : public HloModulePass {
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public:
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explicit TopkRewriter(std::function<bool(const HloSortInstruction*, int64_t)>
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is_profitable_to_convert)
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: is_profitable_to_convert_(std::move(is_profitable_to_convert)) {}
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absl::string_view name() const override { return "topk-rewriter"; }
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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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protected:
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// Check if the sort instruction is in TopK.
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std::optional<int64_t> SortIsInTopK(HloInstruction* inst);
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// Transform to CustomCall.
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StatusOr<bool> TransformToCustomCall(
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HloModule* module,
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const absl::flat_hash_set<absl::string_view>& execution_threads);
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private:
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// Predicate that returns true if a sort instruction is profitable to be
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// converted into a custom call.
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std::function<bool(const HloSortInstruction*, int64_t)>
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is_profitable_to_convert_;
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// Matches the input to the sort+iota+slice pattern and converts to custom
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// call if profitable. Returns the custom call if one was created.
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StatusOr<HloInstruction*> TransformPatternToCustomCall(HloInstruction* inst);
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};
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class TopkDecomposer : public HloModulePass {
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public:
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absl::string_view name() const override { return "topk-decomposer"; }
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explicit TopkDecomposer(HloPredicate should_decompose = {})
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: should_decompose_(should_decompose) {}
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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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HloPredicate should_decompose_;
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};
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} // namespace xla
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#endif // XLA_SERVICE_TOPK_REWRITER_H_
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