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/*========================== begin_copyright_notice ============================
Copyright (C) 2017-2024 Intel Corporation
SPDX-License-Identifier: MIT
============================= end_copyright_notice ===========================*/
/*========================== begin_copyright_notice ============================
This file is distributed under the University of Illinois Open Source License.
See LICENSE.TXT for details.
============================= end_copyright_notice ===========================*/
#pragma once
#include "Compiler/CodeGenContextWrapper.hpp"
#include "common/LLVMWarningsPush.hpp"
#include <llvm/Analysis/PostDominators.h>
#include <llvm/Analysis/LoopInfo.h>
#include "common/LLVMWarningsPop.hpp"
namespace IGC {
class HoistCongruentPHI : public llvm::FunctionPass {
llvm::DominatorTree* DT = nullptr;
CodeGenContext* CTX = nullptr;
public:
static char ID; // Pass identification
HoistCongruentPHI();
virtual bool runOnFunction(llvm::Function& F) override;
virtual void getAnalysisUsage(llvm::AnalysisUsage& AU) const override {
AU.setPreservesCFG();
AU.addRequired<llvm::DominatorTreeWrapperPass>();
AU.addRequired<CodeGenContextWrapper>();
AU.addPreserved<llvm::DominatorTreeWrapperPass>();
}
private:
// try to hoist phi nodes with congruent incoming values
typedef std::pair<llvm::Instruction*, llvm::Instruction*> InstPair;
typedef llvm::SmallVector<llvm::Instruction*, 4> InstVec;
void appendIfNotExist(InstPair src, std::vector<InstPair> &instMap)
{
if (std::find(instMap.begin(), instMap.end(), src) == instMap.end())
{
instMap.push_back(src);
}
}
void appendIfNotExist(InstVec& dst, llvm::Instruction* inst)
{
if (std::find(dst.begin(), dst.end(), inst) == dst.end())
{
dst.push_back(inst);
}
}
void appendIfNotExist(InstVec& dst, InstVec& src)
{
for (auto* I : src)
{
appendIfNotExist(dst, I);
}
}
// check if two values are congruent (derived from same values), and
// record all intermediate results in vector.
bool checkCongruent(std::vector<InstPair> &instMap, const InstPair& values, InstVec& leaves, unsigned depth);
/**
* Detech phi with congruent incoming values, and try to hoist them to
* dominator. In some cases, GVN may leave code like this and increase
* register pressure.
*/
bool hoistCongruentPhi(llvm::PHINode* phi);
bool hoistCongruentPhi(llvm::Function& F);
};
void initializeHoistCongruentPHIPass(llvm::PassRegistry&);
}
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