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https://github.com/KhronosGroup/SPIRV-Tools
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c8e1588cfa
This adds two passes to accomplish this: one pass to analyze a shader to determine the input slots that are live. The second pass is run on the preceding shader to eliminate any stores to output slots that are not consumed by the following shader. These passes support vert, tesc, tese, geom, and frag shaders. These passes are currently only available through the API. These passes together with dead code elimination, and elimination of dead input and output components and variables (WIP), will allow users to do dead code elimination across shader boundaries.
88 lines
2.8 KiB
C++
88 lines
2.8 KiB
C++
// Copyright (c) 2022 The Khronos Group Inc.
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// Copyright (c) 2022 LunarG Inc.
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//
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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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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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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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#ifndef SOURCE_OPT_ELIMINATE_DEAD_OUTPUT_STORES_H_
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#define SOURCE_OPT_ELIMINATE_DEAD_OUTPUT_STORES_H_
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#include <unordered_set>
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#include "source/opt/ir_context.h"
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#include "source/opt/module.h"
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#include "source/opt/pass.h"
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namespace spvtools {
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namespace opt {
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// See optimizer.hpp for documentation.
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class EliminateDeadOutputStoresPass : public Pass {
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public:
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explicit EliminateDeadOutputStoresPass(
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std::unordered_set<uint32_t>* live_locs,
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std::unordered_set<uint32_t>* live_builtins)
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: live_locs_(live_locs), live_builtins_(live_builtins) {}
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const char* name() const override { return "eliminate-dead-output-stores"; }
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Status Process() override;
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// Return the mask of preserved Analyses.
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IRContext::Analysis GetPreservedAnalyses() override {
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return IRContext::kAnalysisDefUse |
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IRContext::kAnalysisInstrToBlockMapping |
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IRContext::kAnalysisCombinators | IRContext::kAnalysisCFG |
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IRContext::kAnalysisDominatorAnalysis |
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IRContext::kAnalysisLoopAnalysis | IRContext::kAnalysisNameMap |
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IRContext::kAnalysisConstants | IRContext::kAnalysisTypes;
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}
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private:
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// Initialize elimination
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void InitializeElimination();
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// Do dead output store analysis
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Status DoDeadOutputStoreAnalysis();
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// Do dead output store analysis
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Status DoDeadOutputStoreElimination();
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// Mark all locations live
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void MarkAllLocsLive();
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// Kill all stores resulting from |ref|.
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void KillAllStoresOfRef(Instruction* ref);
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// Kill all dead stores resulting from |user| of loc-based |var|.
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void KillAllDeadStoresOfLocRef(Instruction* user, Instruction* var);
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// Kill all dead stores resulting from |user| of builtin |var|.
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void KillAllDeadStoresOfBuiltinRef(Instruction* user, Instruction* var);
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// Return true if any of |count| locations starting at location |start| are
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// live.
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bool AnyLocsAreLive(uint32_t start, uint32_t count);
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// Return true if builtin |bi| is live.
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bool IsLiveBuiltin(uint32_t bi);
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std::unordered_set<uint32_t>* live_locs_;
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std::unordered_set<uint32_t>* live_builtins_;
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std::vector<Instruction*> kill_list_;
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};
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} // namespace opt
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} // namespace spvtools
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#endif // SOURCE_OPT_ELIMINATE_DEAD_OUTPUT_STORES_H_
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