Imported Upstream version 5.18.0.247

Former-commit-id: 2d6af2e4ed0eda5cbdc2946446ef7718456ad190

external/llvm/lib/Transforms/Scalar/LowerAtomic.cpp

@@ -1,172 +0,0 @@
-//===- LowerAtomic.cpp - Lower atomic intrinsics --------------------------===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// This pass lowers atomic intrinsics to non-atomic form for use in a known
-// non-preemptible environment.
-//
-//===----------------------------------------------------------------------===//
-
-#include "llvm/Transforms/Scalar/LowerAtomic.h"
-#include "llvm/IR/Function.h"
-#include "llvm/IR/IRBuilder.h"
-#include "llvm/Pass.h"
-#include "llvm/Transforms/Scalar.h"
-using namespace llvm;
-
-#define DEBUG_TYPE "loweratomic"
-
-static bool LowerAtomicCmpXchgInst(AtomicCmpXchgInst *CXI) {
-  IRBuilder<> Builder(CXI);
-  Value *Ptr = CXI->getPointerOperand();
-  Value *Cmp = CXI->getCompareOperand();
-  Value *Val = CXI->getNewValOperand();
-
-  LoadInst *Orig = Builder.CreateLoad(Ptr);
-  Value *Equal = Builder.CreateICmpEQ(Orig, Cmp);
-  Value *Res = Builder.CreateSelect(Equal, Val, Orig);
-  Builder.CreateStore(Res, Ptr);
-
-  Res = Builder.CreateInsertValue(UndefValue::get(CXI->getType()), Orig, 0);
-  Res = Builder.CreateInsertValue(Res, Equal, 1);
-
-  CXI->replaceAllUsesWith(Res);
-  CXI->eraseFromParent();
-  return true;
-}
-
-static bool LowerAtomicRMWInst(AtomicRMWInst *RMWI) {
-  IRBuilder<> Builder(RMWI);
-  Value *Ptr = RMWI->getPointerOperand();
-  Value *Val = RMWI->getValOperand();
-
-  LoadInst *Orig = Builder.CreateLoad(Ptr);
-  Value *Res = nullptr;
-
-  switch (RMWI->getOperation()) {
-  default: llvm_unreachable("Unexpected RMW operation");
-  case AtomicRMWInst::Xchg:
-    Res = Val;
-    break;
-  case AtomicRMWInst::Add:
-    Res = Builder.CreateAdd(Orig, Val);
-    break;
-  case AtomicRMWInst::Sub:
-    Res = Builder.CreateSub(Orig, Val);
-    break;
-  case AtomicRMWInst::And:
-    Res = Builder.CreateAnd(Orig, Val);
-    break;
-  case AtomicRMWInst::Nand:
-    Res = Builder.CreateNot(Builder.CreateAnd(Orig, Val));
-    break;
-  case AtomicRMWInst::Or:
-    Res = Builder.CreateOr(Orig, Val);
-    break;
-  case AtomicRMWInst::Xor:
-    Res = Builder.CreateXor(Orig, Val);
-    break;
-  case AtomicRMWInst::Max:
-    Res = Builder.CreateSelect(Builder.CreateICmpSLT(Orig, Val),
-                               Val, Orig);
-    break;
-  case AtomicRMWInst::Min:
-    Res = Builder.CreateSelect(Builder.CreateICmpSLT(Orig, Val),
-                               Orig, Val);
-    break;
-  case AtomicRMWInst::UMax:
-    Res = Builder.CreateSelect(Builder.CreateICmpULT(Orig, Val),
-                               Val, Orig);
-    break;
-  case AtomicRMWInst::UMin:
-    Res = Builder.CreateSelect(Builder.CreateICmpULT(Orig, Val),
-                               Orig, Val);
-    break;
-  }
-  Builder.CreateStore(Res, Ptr);
-  RMWI->replaceAllUsesWith(Orig);
-  RMWI->eraseFromParent();
-  return true;
-}
-
-static bool LowerFenceInst(FenceInst *FI) {
-  FI->eraseFromParent();
-  return true;
-}
-
-static bool LowerLoadInst(LoadInst *LI) {
-  LI->setAtomic(AtomicOrdering::NotAtomic);
-  return true;
-}
-
-static bool LowerStoreInst(StoreInst *SI) {
-  SI->setAtomic(AtomicOrdering::NotAtomic);
-  return true;
-}
-
-static bool runOnBasicBlock(BasicBlock &BB) {
-  bool Changed = false;
-  for (BasicBlock::iterator DI = BB.begin(), DE = BB.end(); DI != DE;) {
-    Instruction *Inst = &*DI++;
-    if (FenceInst *FI = dyn_cast<FenceInst>(Inst))
-      Changed |= LowerFenceInst(FI);
-    else if (AtomicCmpXchgInst *CXI = dyn_cast<AtomicCmpXchgInst>(Inst))
-      Changed |= LowerAtomicCmpXchgInst(CXI);
-    else if (AtomicRMWInst *RMWI = dyn_cast<AtomicRMWInst>(Inst))
-      Changed |= LowerAtomicRMWInst(RMWI);
-    else if (LoadInst *LI = dyn_cast<LoadInst>(Inst)) {
-      if (LI->isAtomic())
-        LowerLoadInst(LI);
-    } else if (StoreInst *SI = dyn_cast<StoreInst>(Inst)) {
-      if (SI->isAtomic())
-        LowerStoreInst(SI);
-    }
-  }
-  return Changed;
-}
-
-static bool lowerAtomics(Function &F) {
-  bool Changed = false;
-  for (BasicBlock &BB : F) {
-    Changed |= runOnBasicBlock(BB);
-  }
-  return Changed;
-}
-
-PreservedAnalyses LowerAtomicPass::run(Function &F, FunctionAnalysisManager &) {
-  if (lowerAtomics(F))
-    return PreservedAnalyses::none();
-  return PreservedAnalyses::all();
-}
-
-namespace {
-class LowerAtomicLegacyPass : public FunctionPass {
-public:
-  static char ID;
-
-  LowerAtomicLegacyPass() : FunctionPass(ID) {
-    initializeLowerAtomicLegacyPassPass(*PassRegistry::getPassRegistry());
-  }
-
-  bool runOnFunction(Function &F) override {
-    // Don't skip optnone functions; atomics still need to be lowered.
-    FunctionAnalysisManager DummyFAM;
-    auto PA = Impl.run(F, DummyFAM);
-    return !PA.areAllPreserved();
-  }
-
-private:
-  LowerAtomicPass Impl;
-  };
-}
-
-char LowerAtomicLegacyPass::ID = 0;
-INITIALIZE_PASS(LowerAtomicLegacyPass, "loweratomic",
-                "Lower atomic intrinsics to non-atomic form", false, false)
-
-Pass *llvm::createLowerAtomicPass() { return new LowerAtomicLegacyPass(); }