SPIRV-Tools/source/opt/dead_insert_elim_pass.h
Steven Perron 06cdb96984 Make use of the instruction folder.
Implementation of the simplification pass.

- Create pass that calls the instruction folder on each instruction and
  propagate instructions that fold to a copy.  This will do copy
  propagation as well.

- Did not use the propagator engine because I want to modify the instruction
  as we go along.

- Change folding to not allocate new instructions, but make changes in
  place.  This change had a big impact on compile time.

- Add simplification pass to the legalization passes in place of
  insert-extract elimination.

- Added test cases for new folding rules.

- Added tests for the simplification pass

- Added a method to the CFG to apply a function to the basic blocks in
  reverse post order.

Contributes to #1164.
2018-02-07 23:01:47 -05:00

89 lines
3.0 KiB
C++

// Copyright (c) 2018 The Khronos Group Inc.
// Copyright (c) 2018 Valve Corporation
// Copyright (c) 2018 LunarG Inc.
//
// 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_DEAD_INSERT_ELIM_PASS_H_
#define LIBSPIRV_OPT_DEAD_INSERT_ELIM_PASS_H_
#include <algorithm>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include "basic_block.h"
#include "def_use_manager.h"
#include "ir_context.h"
#include "mem_pass.h"
#include "module.h"
namespace spvtools {
namespace opt {
// See optimizer.hpp for documentation.
class DeadInsertElimPass : public MemPass {
public:
DeadInsertElimPass();
const char* name() const override { return "eliminate-dead-inserts"; }
Status Process(ir::IRContext*) override;
private:
// Return the number of subcomponents in the composite type |typeId|.
// Return 0 if not a composite type or number of components is not a
// 32-bit constant.
uint32_t NumComponents(ir::Instruction* typeInst);
// Mark all inserts in instruction chain ending at |insertChain| with
// indices that intersect with extract indices |extIndices| starting with
// index at |extOffset|. Chains are composed solely of Inserts and Phis.
// Mark all inserts in chain if |extIndices| is nullptr.
void MarkInsertChain(ir::Instruction* insertChain,
std::vector<uint32_t>* extIndices, uint32_t extOffset);
// Perform EliminateDeadInsertsOnePass(|func|) until no modification is
// made. Return true if modified.
bool EliminateDeadInserts(ir::Function* func);
// DCE all dead struct, matrix and vector inserts in |func|. An insert is
// dead if the value it inserts is never used. Replace any reference to the
// insert with its original composite. Return true if modified. Dead inserts
// in dependence cycles are not currently eliminated. Dead inserts into
// arrays are not currently eliminated.
bool EliminateDeadInsertsOnePass(ir::Function* func);
// Initialize extensions whitelist
void InitExtensions();
// Return true if all extensions in this module are allowed by this pass.
bool AllExtensionsSupported() const;
void Initialize(ir::IRContext* c);
Pass::Status ProcessImpl();
// Live inserts
std::unordered_set<uint32_t> liveInserts_;
// Visited phis as insert chain is traversed; used to avoid infinite loop
std::unordered_set<uint32_t> visitedPhis_;
// Extensions supported by this pass.
std::unordered_set<std::string> extensions_whitelist_;
};
} // namespace opt
} // namespace spvtools
#endif // LIBSPIRV_OPT_DEAD_INSERT_ELIM_PASS_H_