//===-- NVPTXAtomicLower.cpp - Lower atomics of local memory ----*- C++ -*-===//

//

// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.

// See https://llvm.org/LICENSE.txt for license information.

// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

//

//===----------------------------------------------------------------------===//

//

//  Lower atomics of local memory to simple load/stores

//

//===----------------------------------------------------------------------===//

#include "NVPTXAtomicLower.h"

#include "llvm/CodeGen/StackProtector.h"

#include "llvm/IR/Constants.h"

#include "llvm/IR/Function.h"

#include "llvm/IR/IRBuilder.h"

#include "llvm/IR/InstIterator.h"

#include "llvm/IR/Instructions.h"

#include "llvm/Transforms/Utils/LowerAtomic.h"

#include "MCTargetDesc/NVPTXBaseInfo.h"

using namespace llvm;

namespace {

// Hoisting the alloca instructions in the non-entry blocks to the entry

// block.

class NVPTXAtomicLower : public FunctionPass {

public:

  static char ID; // Pass ID

  NVPTXAtomicLower() : FunctionPass(ID) {}

  void getAnalysisUsage(AnalysisUsage &AU) const override {

    AU.setPreservesCFG();

  }

  StringRef getPassName() const override {

    return "NVPTX lower atomics of local memory";

  }

  bool runOnFunction(Function &F) override;

};

} // namespace

bool NVPTXAtomicLower::runOnFunction(Function &F) {

  SmallVector<AtomicRMWInst *> LocalMemoryAtomics;

  for (Instruction &I : instructions(F))

    if (AtomicRMWInst *RMWI = dyn_cast<AtomicRMWInst>(&I))

      if (RMWI->getPointerAddressSpace() == ADDRESS_SPACE_LOCAL)

        LocalMemoryAtomics.push_back(RMWI);

  bool Changed = false;

  for (AtomicRMWInst *RMWI : LocalMemoryAtomics)

    Changed |= lowerAtomicRMWInst(RMWI);

  return Changed;

}

char NVPTXAtomicLower::ID = 0;

namespace llvm {

void initializeNVPTXAtomicLowerPass(PassRegistry &);

}

INITIALIZE_PASS(NVPTXAtomicLower, "nvptx-atomic-lower",

                "Lower atomics of local memory to simple load/stores", false,

                false)

FunctionPass *llvm::createNVPTXAtomicLowerPass() {

  return new NVPTXAtomicLower();

}