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/*========================== begin_copyright_notice ============================
Copyright (C) 2024 Intel Corporation
SPDX-License-Identifier: MIT
============================= end_copyright_notice ===========================*/
#pragma once
#include "common/LLVMWarningsPush.hpp"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Pass.h"
#include "common/LLVMWarningsPop.hpp"
namespace llvm {
class AllocaInst;
} // namespace llvm
namespace IGC {
////////////////////////////////////////////////////////////////////////////////
/// This pass analyzes all uses of array-of-vector allocas to find unused
/// vector elements. The type of alloca is modified to remove the unused vector
/// elements, e.g., the following piece of IR:
///
/// %alloca = alloca [64 x <4 x float>], align 16
/// %addr = getelementptr [64 x <4 x float>], [64 x <4 x float>]* %alloca, i32 0, i32 %index
/// %vec = load <4 x float>, <4 x float>* %addr1
/// %a = extractelement <4 x float> %vec1, i64 2
/// ret float %a
///
/// is transformed to:
///
/// %alloca = alloca [64 x float], align 16
/// %addr = getelementptr [64 x float], [64 x float]* %alloca, i32 0, i32 %index
/// %a = load float, float* %addr1
/// ret float %a
///////////////////////////////////////////////////////////////////////////////
class ShrinkArrayAllocaPass : public llvm::FunctionPass {
public:
static char ID;
ShrinkArrayAllocaPass();
~ShrinkArrayAllocaPass() {};
virtual bool runOnFunction(llvm::Function &function) override;
virtual llvm::StringRef getPassName() const override;
private:
void GatherAllocas(llvm::Function &F);
bool Resolve();
private:
using UsageInfo = llvm::SmallVector<bool, 4>;
llvm::SmallVector<std::pair<llvm::AllocaInst *, UsageInfo>, 4> m_AllocaInfo;
};
void initializeShrinkArrayAllocaPassPass(llvm::PassRegistry &);
} // namespace IGC
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