SPIRV-Tools/source/opt/strength_reduction_pass.h
2022-01-12 19:04:13 -05:00

66 lines
2.2 KiB
C++

// Copyright (c) 2017 Google 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 SOURCE_OPT_STRENGTH_REDUCTION_PASS_H_
#define SOURCE_OPT_STRENGTH_REDUCTION_PASS_H_
#include "source/opt/def_use_manager.h"
#include "source/opt/ir_context.h"
#include "source/opt/module.h"
#include "source/opt/pass.h"
namespace spvtools {
namespace opt {
// See optimizer.hpp for documentation.
class StrengthReductionPass : public Pass {
public:
const char* name() const override { return "strength-reduction"; }
Status Process() override;
private:
// Replaces multiple by power of 2 with an equivalent bit shift.
// Returns true if something changed.
bool ReplaceMultiplyByPowerOf2(BasicBlock::iterator*);
// Scan the types and constants in the module looking for the integer
// types that we are
// interested in. The shift operation needs a small unsigned integer. We
// need to find
// them or create them. We do not want duplicates.
void FindIntTypesAndConstants();
// Get the id for the given constant. If it does not exist, it will be
// created. The parameter must be between 0 and 32 inclusive.
uint32_t GetConstantId(uint32_t);
// Replaces certain instructions in function bodies with presumably cheaper
// ones. Returns true if something changed.
bool ScanFunctions();
// Type ids for the types of interest, or 0 if they do not exist.
uint32_t int32_type_id_;
uint32_t uint32_type_id_;
// constant_ids[i] is the id for unsigned integer constant i.
// We set the limit at 32 because a bit shift of a 32-bit integer does not
// need a value larger than 32.
uint32_t constant_ids_[33];
};
} // namespace opt
} // namespace spvtools
#endif // SOURCE_OPT_STRENGTH_REDUCTION_PASS_H_