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/*========================== begin_copyright_notice ============================
Copyright (C) 2017-2022 Intel Corporation
SPDX-License-Identifier: MIT
============================= end_copyright_notice ===========================*/
#pragma once
#include "common/LLVMWarningsPush.hpp"
#include <llvm/Pass.h>
#include <llvm/IR/InstVisitor.h>
#include "common/LLVMWarningsPop.hpp"
#include "Compiler/CISACodeGen/WIAnalysis.hpp"
namespace IGC {
// This pass performs the following optimization:
//
// It replaces the work group reduce instruction which is only used by
// the work item with local or global id = 0 an optimised reduce.
// An optimized reduce uses non-zero work items less than a regular one.
// Applies to workspace dimension equals 3 only.
class ReduceOptPass : public llvm::FunctionPass {
public:
static char ID;
ReduceOptPass();
virtual llvm::StringRef getPassName() const override { return "Reduce Optimisation Pass"; }
virtual bool runOnFunction(llvm::Function &F) override;
private:
// This function recursively checks if the result of the reduce
// function is only used by the work item with the local_linear_id == 0
// or global_linear_id == 0.
bool checkUsers(llvm::Value *MainVal, llvm::Value *Val, llvm::BasicBlock *BB);
// Helper functions for checking the condition of using the reduce result
bool checkSelect(llvm::Instruction *Sel);
bool checkBranch(llvm::BasicBlock *Bb);
bool checkCmp(llvm::Value *Val);
bool checkGlobalId(llvm::Value *Val);
bool checkLocalId(llvm::Value *Val);
bool checkBuiltInName(llvm::Value *I, const std::string &Name);
bool createReduceWI0(llvm::Instruction *ReduceInstr);
bool Changed = false;
llvm::Module *M = nullptr;
};
} // namespace IGC
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