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/*========================== begin_copyright_notice ============================
Copyright (C) 2018-2021 Intel Corporation
SPDX-License-Identifier: MIT
============================= end_copyright_notice ===========================*/
#include "Compiler/CodeGenPublic.h"
#include "Compiler/IGCPassSupport.h"
#include "common/LLVMWarningsPush.hpp"
#include <llvm/IR/Function.h>
#include <llvm/IR/Instructions.h>
#include <llvm/IR/InstVisitor.h>
#include "common/LLVMWarningsPop.hpp"
using namespace llvm;
using namespace IGC;
namespace {
class MarkReadOnlyLoad : public FunctionPass, public InstVisitor<MarkReadOnlyLoad> {
public:
static char ID;
MarkReadOnlyLoad();
~MarkReadOnlyLoad() {}
StringRef getPassName() const override { return "MarkReadOnlyLoadPass"; }
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.addRequired<CodeGenContextWrapper>();
AU.setPreservesCFG();
}
bool runOnFunction(Function &F) override;
void visitLoadInst(LoadInst &LI);
private:
MDNode *m_mdNode = nullptr;
bool m_changed{};
};
} // namespace
namespace IGC {
FunctionPass *createMarkReadOnlyLoadPass() { return new MarkReadOnlyLoad(); }
} // namespace IGC
#define PASS_FLAG "mark-readonly-load"
#define PASS_DESCRIPTION "Mark readonly load"
#define PASS_CFG_ONLY false
#define PASS_ANALYSIS false
IGC_INITIALIZE_PASS_BEGIN(MarkReadOnlyLoad, PASS_FLAG, PASS_DESCRIPTION, PASS_CFG_ONLY, PASS_ANALYSIS)
IGC_INITIALIZE_PASS_DEPENDENCY(CodeGenContextWrapper)
IGC_INITIALIZE_PASS_END(MarkReadOnlyLoad, PASS_FLAG, PASS_DESCRIPTION, PASS_CFG_ONLY, PASS_ANALYSIS)
char MarkReadOnlyLoad::ID = 0;
MarkReadOnlyLoad::MarkReadOnlyLoad() : FunctionPass(ID) {
initializeMarkReadOnlyLoadPass(*PassRegistry::getPassRegistry());
}
bool MarkReadOnlyLoad::runOnFunction(Function &F) {
m_changed = false;
m_mdNode = MDNode::get(F.getContext(), nullptr);
visit(F);
return m_changed;
}
void MarkReadOnlyLoad::visitLoadInst(LoadInst &LI) {
bool isRO = false;
if (LI.getPointerAddressSpace() == ADDRESS_SPACE_CONSTANT) {
isRO = true;
} else if (auto *srcPtr = TracePointerSource(LI.getPointerOperand())) {
if (isa<GenIntrinsicInst>(srcPtr)) {
unsigned bufId = 0;
BufferType bufTy;
BufferAccessType accTy;
bool needBufferOffset = false; // Unused
// check whether we are doing read only access on buffer (e.g. on UAV)
if (GetResourcePointerInfo(srcPtr, bufId, bufTy, accTy, needBufferOffset)) {
if (accTy == BufferAccessType::ACCESS_READ) {
isRO = true;
}
}
}
}
if (isRO) {
m_changed = true;
LI.setMetadata(LLVMContext::MD_invariant_load, m_mdNode);
}
}
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