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// Copyright (c) 2018 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef LIBSPIRV_OPT_IF_CONVERSION_H_
#define LIBSPIRV_OPT_IF_CONVERSION_H_
#include "basic_block.h"
#include "ir_builder.h"
#include "pass.h"
#include "types.h"
namespace spvtools {
namespace opt {
// See optimizer.hpp for documentation.
class IfConversion : public Pass {
public:
const char* name() const override { return "if-conversion"; }
Status Process() override;
IRContext::Analysis GetPreservedAnalyses() override {
return IRContext::kAnalysisDefUse | IRContext::kAnalysisDominatorAnalysis |
IRContext::kAnalysisInstrToBlockMapping | IRContext::kAnalysisCFG |
IRContext::kAnalysisNameMap;
}
private:
// Returns true if |id| is a valid type for use with OpSelect. OpSelect only
// allows scalars, vectors and pointers as valid inputs.
bool CheckType(uint32_t id);
// Returns the basic block containing |id|.
BasicBlock* GetBlock(uint32_t id);
// Returns the basic block for the |predecessor|'th index predecessor of
// |phi|.
BasicBlock* GetIncomingBlock(Instruction* phi, uint32_t predecessor);
// Returns the instruction defining the |predecessor|'th index of |phi|.
Instruction* GetIncomingValue(Instruction* phi, uint32_t predecessor);
// Returns the id of a OpCompositeConstruct boolean vector. The composite has
// the same number of elements as |vec_data_ty| and each member is |cond|.
// |where| indicates the location in |block| to insert the composite
// construct. If necessary, this function will also construct the necessary
// type instructions for the boolean vector.
uint32_t SplatCondition(analysis::Vector* vec_data_ty, uint32_t cond,
InstructionBuilder* builder);
// Returns true if none of |phi|'s users are in |block|.
bool CheckPhiUsers(Instruction* phi, BasicBlock* block);
// Returns |false| if |block| is not appropriate to transform. Only
// transforms blocks with two predecessors. Neither incoming block can be
// dominated by |block|. Both predecessors must share a common dominator that
// is terminated by a conditional branch.
bool CheckBlock(BasicBlock* block, DominatorAnalysis* dominators,
BasicBlock** common);
// Moves |inst| to |target_block| if it does not already dominate the block.
// Any instructions that |inst| depends on are move if necessary. It is
// assumed that |inst| can be hoisted to |target_block| as defined by
// |CanHoistInstruction|. |dominators| is the dominator analysis for the
// function that contains |target_block|.
void HoistInstruction(Instruction* inst, BasicBlock* target_block,
DominatorAnalysis* dominators);
// Returns true if it is legal to move |inst| and the instructions it depends
// on to |target_block| if they do not already dominate |target_block|.
bool CanHoistInstruction(Instruction* inst, BasicBlock* target_block,
DominatorAnalysis* dominators);
};
} // namespace opt
} // namespace spvtools
#endif // LIBSPIRV_OPT_IF_CONVERSION_H_
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