X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FAtomicExpandPass.cpp;fp=lib%2FCodeGen%2FAtomicExpandPass.cpp;h=c8308afe9c1450d1fa2b7215250779e7be1ef703;hb=81d225b93d55ec44d6e79f2d95440f250f3df064;hp=faf951985a7120564454b71eeb9cfa327cfac743;hpb=59278dfa2316824957b2633f5030103965030643;p=oota-llvm.git

diff --git a/lib/CodeGen/AtomicExpandPass.cpp b/lib/CodeGen/AtomicExpandPass.cpp
index faf951985a7..c8308afe9c1 100644
--- a/lib/CodeGen/AtomicExpandPass.cpp
+++ b/lib/CodeGen/AtomicExpandPass.cpp
@@ -34,6 +34,7 @@
 #include "llvm/Target/TargetLowering.h"
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Target/TargetSubtargetInfo.h"
+#include "llvm/Transforms/Utils/BasicBlockUtils.h"
 
 using namespace llvm;
 
@@ -82,764 +83,6 @@ FunctionPass *llvm::createAtomicExpandPass(const TargetMachine *TM) {
   return new AtomicExpand(TM);
 }
 
-
-namespace {
-
-bool StoreAddressDependOnValue(StoreInst* SI, Value* DepVal);
-Value* GetUntaintedAddress(Value* CurrentAddress);
-
-// The depth we trace down a variable to look for its dependence set.
-const unsigned kDependenceDepth = 4;
-
-// Recursively looks for variables that 'Val' depends on at the given depth
-// 'Depth', and adds them in 'DepSet'. If 'InsertOnlyLeafNodes' is true, only
-// inserts the leaf node values; otherwise, all visited nodes are included in
-// 'DepSet'. Note that constants will be ignored.
-template <typename SetType>
-void recursivelyFindDependence(SetType* DepSet, Value* Val,
-                               bool InsertOnlyLeafNodes = false,
-                               unsigned Depth = kDependenceDepth) {
-  if (Val == nullptr) {
-    return;
-  }
-  if (!InsertOnlyLeafNodes && !isa<Constant>(Val)) {
-    DepSet->insert(Val);
-  }
-  if (Depth == 0) {
-    // Cannot go deeper. Insert the leaf nodes.
-    if (InsertOnlyLeafNodes && !isa<Constant>(Val)) {
-      DepSet->insert(Val);
-    }
-    return;
-  }
-
-  // Go one step further to explore the dependence of the operands.
-  Instruction* I = nullptr;
-  if ((I = dyn_cast<Instruction>(Val))) {
-    if (isa<LoadInst>(I)) {
-      // A load is considerd the leaf load of the dependence tree. Done.
-      DepSet->insert(Val);
-      return;
-    } else if (I->isBinaryOp()) {
-      BinaryOperator* I = dyn_cast<BinaryOperator>(Val);
-      Value *Op0 = I->getOperand(0), *Op1 = I->getOperand(1);
-      recursivelyFindDependence(DepSet, Op0, Depth - 1);
-      recursivelyFindDependence(DepSet, Op1, Depth - 1);
-    } else if (I->isCast()) {
-      Value* Op0 = I->getOperand(0);
-      recursivelyFindDependence(DepSet, Op0, Depth - 1);
-    } else if (I->getOpcode() == Instruction::Select) {
-      Value* Op0 = I->getOperand(0);
-      Value* Op1 = I->getOperand(1);
-      Value* Op2 = I->getOperand(2);
-      recursivelyFindDependence(DepSet, Op0, Depth - 1);
-      recursivelyFindDependence(DepSet, Op1, Depth - 1);
-      recursivelyFindDependence(DepSet, Op2, Depth - 1);
-    } else if (I->getOpcode() == Instruction::GetElementPtr) {
-      for (unsigned i = 0; i < I->getNumOperands(); i++) {
-        recursivelyFindDependence(DepSet, I->getOperand(i), Depth - 1);
-      }
-    } else if (I->getOpcode() == Instruction::Store) {
-      auto* SI = dyn_cast<StoreInst>(Val);
-      recursivelyFindDependence(DepSet, SI->getPointerOperand(), Depth - 1);
-      recursivelyFindDependence(DepSet, SI->getValueOperand(), Depth - 1);
-    } else {
-      Value* Op0 = nullptr;
-      Value* Op1 = nullptr;
-      switch (I->getOpcode()) {
-        case Instruction::ICmp:
-        case Instruction::FCmp: {
-          Op0 = I->getOperand(0);
-          Op1 = I->getOperand(1);
-          recursivelyFindDependence(DepSet, Op0, Depth - 1);
-          recursivelyFindDependence(DepSet, Op1, Depth - 1);
-          break;
-        }
-        default: {
-          // Be conservative. Add it and be done with it.
-          DepSet->insert(Val);
-          return;
-        }
-      }
-    }
-  } else if (isa<Constant>(Val)) {
-    // Not interested in constant values. Done.
-    return;
-  } else {
-    // Be conservative. Add it and be done with it.
-    DepSet->insert(Val);
-    return;
-  }
-}
-
-// Helper function to create a Cast instruction.
-Value* createCast(IRBuilder<true, NoFolder>& Builder, Value* DepVal,
-                  Type* TargetIntegerType) {
-  Instruction::CastOps CastOp = Instruction::BitCast;
-  switch (DepVal->getType()->getTypeID()) {
-    case Type::IntegerTyID: {
-      CastOp = Instruction::SExt;
-      break;
-    }
-    case Type::FloatTyID:
-    case Type::DoubleTyID: {
-      CastOp = Instruction::FPToSI;
-      break;
-    }
-    case Type::PointerTyID: {
-      CastOp = Instruction::PtrToInt;
-      break;
-    }
-    default: { break; }
-  }
-
-  return Builder.CreateCast(CastOp, DepVal, TargetIntegerType);
-}
-
-// Given a value, if it's a tainted address, this function returns the
-// instruction that ORs the "dependence value" with the "original address".
-// Otherwise, returns nullptr.  This instruction is the first OR instruction
-// where one of its operand is an AND instruction with an operand being 0.
-//
-// E.g., it returns '%4 = or i32 %3, %2' given 'CurrentAddress' is '%5'.
-// %0 = load i32, i32* @y, align 4, !tbaa !1
-// %cmp = icmp ne i32 %0, 42  // <== this is like the condition
-// %1 = sext i1 %cmp to i32
-// %2 = ptrtoint i32* @x to i32
-// %3 = and i32 %1, 0
-// %4 = or i32 %3, %2
-// %5 = inttoptr i32 %4 to i32*
-// store i32 1, i32* %5, align 4
-Instruction* getOrAddress(Value* CurrentAddress) {
-  // Is it a cast from integer to pointer type.
-  Instruction* OrAddress = nullptr;
-  Instruction* AndDep = nullptr;
-  Instruction* CastToInt = nullptr;
-  Value* ActualAddress = nullptr;
-  Constant* ZeroConst = nullptr;
-
-  const Instruction* CastToPtr = dyn_cast<Instruction>(CurrentAddress);
-  if (CastToPtr && CastToPtr->getOpcode() == Instruction::IntToPtr) {
-    // Is it an OR instruction: %1 = or %and, %actualAddress.
-    if ((OrAddress = dyn_cast<Instruction>(CastToPtr->getOperand(0))) &&
-        OrAddress->getOpcode() == Instruction::Or) {
-      // The first operand should be and AND instruction.
-      AndDep = dyn_cast<Instruction>(OrAddress->getOperand(0));
-      if (AndDep && AndDep->getOpcode() == Instruction::And) {
-        // Also make sure its first operand of the "AND" is 0, or the "AND" is
-        // marked explicitly by "NoInstCombine".
-        if ((ZeroConst = dyn_cast<Constant>(AndDep->getOperand(1))) &&
-            ZeroConst->isNullValue()) {
-          return OrAddress;
-        }
-      }
-    }
-  }
-  // Looks like it's not been tainted.
-  return nullptr;
-}
-
-// Given a value, if it's a tainted address, this function returns the
-// instruction that taints the "dependence value". Otherwise, returns nullptr.
-// This instruction is the last AND instruction where one of its operand is 0.
-// E.g., it returns '%3' given 'CurrentAddress' is '%5'.
-// %0 = load i32, i32* @y, align 4, !tbaa !1
-// %cmp = icmp ne i32 %0, 42  // <== this is like the condition
-// %1 = sext i1 %cmp to i32
-// %2 = ptrtoint i32* @x to i32
-// %3 = and i32 %1, 0
-// %4 = or i32 %3, %2
-// %5 = inttoptr i32 %4 to i32*
-// store i32 1, i32* %5, align 4
-Instruction* getAndDependence(Value* CurrentAddress) {
-  // If 'CurrentAddress' is tainted, get the OR instruction.
-  auto* OrAddress = getOrAddress(CurrentAddress);
-  if (OrAddress == nullptr) {
-    return nullptr;
-  }
-
-  // No need to check the operands.
-  auto* AndDepInst = dyn_cast<Instruction>(OrAddress->getOperand(0));
-  assert(AndDepInst);
-  return AndDepInst;
-}
-
-// Given a value, if it's a tainted address, this function returns
-// the "dependence value", which is the first operand in the AND instruction.
-// E.g., it returns '%1' given 'CurrentAddress' is '%5'.
-// %0 = load i32, i32* @y, align 4, !tbaa !1
-// %cmp = icmp ne i32 %0, 42  // <== this is like the condition
-// %1 = sext i1 %cmp to i32
-// %2 = ptrtoint i32* @x to i32
-// %3 = and i32 %1, 0
-// %4 = or i32 %3, %2
-// %5 = inttoptr i32 %4 to i32*
-// store i32 1, i32* %5, align 4
-Value* getDependence(Value* CurrentAddress) {
-  auto* AndInst = getAndDependence(CurrentAddress);
-  if (AndInst == nullptr) {
-    return nullptr;
-  }
-  return AndInst->getOperand(0);
-}
-
-// Given an address that has been tainted, returns the only condition it depends
-// on, if any; otherwise, returns nullptr.
-Value* getConditionDependence(Value* Address) {
-  auto* Dep = getDependence(Address);
-  if (Dep == nullptr) {
-    // 'Address' has not been dependence-tainted.
-    return nullptr;
-  }
-
-  Value* Operand = Dep;
-  while (true) {
-    auto* Inst = dyn_cast<Instruction>(Operand);
-    if (Inst == nullptr) {
-      // Non-instruction type does not have condition dependence.
-      return nullptr;
-    }
-    if (Inst->getOpcode() == Instruction::ICmp) {
-      return Inst;
-    } else {
-      if (Inst->getNumOperands() != 1) {
-        return nullptr;
-      } else {
-        Operand = Inst->getOperand(0);
-      }
-    }
-  }
-}
-
-// Conservatively decides whether the dependence set of 'Val1' includes the
-// dependence set of 'Val2'. If 'ExpandSecondValue' is false, we do not expand
-// 'Val2' and use that single value as its dependence set.
-// If it returns true, it means the dependence set of 'Val1' includes that of
-// 'Val2'; otherwise, it only means we cannot conclusively decide it.
-bool dependenceSetInclusion(Value* Val1, Value* Val2,
-                            int Val1ExpandLevel = 2 * kDependenceDepth,
-                            int Val2ExpandLevel = kDependenceDepth) {
-  typedef SmallSet<Value*, 8> IncludingSet;
-  typedef SmallSet<Value*, 4> IncludedSet;
-
-  IncludingSet DepSet1;
-  IncludedSet DepSet2;
-  // Look for more depths for the including set.
-  recursivelyFindDependence(&DepSet1, Val1, false /*Insert all visited nodes*/,
-                            Val1ExpandLevel);
-  recursivelyFindDependence(&DepSet2, Val2, true /*Only insert leaf nodes*/,
-                            Val2ExpandLevel);
-
-  auto set_inclusion = [](IncludingSet FullSet, IncludedSet Subset) {
-    for (auto* Dep : Subset) {
-      if (0 == FullSet.count(Dep)) {
-        return false;
-      }
-    }
-    return true;
-  };
-  bool inclusion = set_inclusion(DepSet1, DepSet2);
-  DEBUG(dbgs() << "[dependenceSetInclusion]: " << inclusion << "\n");
-  DEBUG(dbgs() << "Including set for: " << *Val1 << "\n");
-  DEBUG(for (const auto* Dep : DepSet1) { dbgs() << "\t\t" << *Dep << "\n"; });
-  DEBUG(dbgs() << "Included set for: " << *Val2 << "\n");
-  DEBUG(for (const auto* Dep : DepSet2) { dbgs() << "\t\t" << *Dep << "\n"; });
-
-  return inclusion;
-}
-
-// Recursively iterates through the operands spawned from 'DepVal'. If there
-// exists a single value that 'DepVal' only depends on, we call that value the
-// root dependence of 'DepVal' and return it. Otherwise, return 'DepVal'.
-Value* getRootDependence(Value* DepVal) {
-  SmallSet<Value*, 8> DepSet;
-  for (unsigned depth = kDependenceDepth; depth > 0; --depth) {
-    recursivelyFindDependence(&DepSet, DepVal, true /*Only insert leaf nodes*/,
-                              depth);
-    if (DepSet.size() == 1) {
-      return *DepSet.begin();
-    }
-    DepSet.clear();
-  }
-  return DepVal;
-}
-
-// This function actually taints 'DepVal' to the address to 'SI'. If the
-// address
-// of 'SI' already depends on whatever 'DepVal' depends on, this function
-// doesn't do anything and returns false. Otherwise, returns true.
-//
-// This effect forces the store and any stores that comes later to depend on
-// 'DepVal'. For example, we have a condition "cond", and a store instruction
-// "s: STORE addr, val". If we want "s" (and any later store) to depend on
-// "cond", we do the following:
-// %conv = sext i1 %cond to i32
-// %addrVal = ptrtoint i32* %addr to i32
-// %andCond = and i32 conv, 0;
-// %orAddr = or i32 %andCond, %addrVal;
-// %NewAddr = inttoptr i32 %orAddr to i32*;
-//
-// This is a more concrete example:
-// ------
-// %0 = load i32, i32* @y, align 4, !tbaa !1
-// %cmp = icmp ne i32 %0, 42  // <== this is like the condition
-// %1 = sext i1 %cmp to i32
-// %2 = ptrtoint i32* @x to i32
-// %3 = and i32 %1, 0
-// %4 = or i32 %3, %2
-// %5 = inttoptr i32 %4 to i32*
-// store i32 1, i32* %5, align 4
-bool taintStoreAddress(StoreInst* SI, Value* DepVal,
-                       const char* calling_func = __builtin_FUNCTION()) {
-  DEBUG(dbgs() << "Called from " << calling_func << '\n');
-  IRBuilder<true, NoFolder> Builder(SI);
-  BasicBlock* BB = SI->getParent();
-  Value* Address = SI->getPointerOperand();
-  Type* TargetIntegerType =
-      IntegerType::get(Address->getContext(),
-                       BB->getModule()->getDataLayout().getPointerSizeInBits());
-
-  // Does SI's address already depends on whatever 'DepVal' depends on?
-  if (StoreAddressDependOnValue(SI, DepVal)) {
-    return false;
-  }
-
-  // Figure out if there's a root variable 'DepVal' depends on. For example, we
-  // can extract "getelementptr inbounds %struct, %struct* %0, i64 0, i32 123"
-  // to be "%struct* %0" since all other operands are constant.
-  DepVal = getRootDependence(DepVal);
-
-  // Is this already a dependence-tainted store?
-  Value* OldDep = getDependence(Address);
-  if (OldDep) {
-    // The address of 'SI' has already been tainted.  Just need to absorb the
-    // DepVal to the existing dependence in the address of SI.
-    Instruction* AndDep = getAndDependence(Address);
-    IRBuilder<true, NoFolder> Builder(AndDep);
-    Value* NewDep = nullptr;
-    if (DepVal->getType() == AndDep->getType()) {
-      NewDep = Builder.CreateAnd(OldDep, DepVal);
-    } else {
-      NewDep = Builder.CreateAnd(
-          OldDep, createCast(Builder, DepVal, TargetIntegerType));
-    }
-
-    auto* NewDepInst = dyn_cast<Instruction>(NewDep);
-
-    // Use the new AND instruction as the dependence
-    AndDep->setOperand(0, NewDep);
-    return true;
-  }
-
-  // SI's address has not been tainted. Now taint it with 'DepVal'.
-  Value* CastDepToInt = createCast(Builder, DepVal, TargetIntegerType);
-  Value* PtrToIntCast = Builder.CreatePtrToInt(Address, TargetIntegerType);
-  Value* AndDepVal =
-      Builder.CreateAnd(CastDepToInt, ConstantInt::get(TargetIntegerType, 0));
-  auto AndInst = dyn_cast<Instruction>(AndDepVal);
-  // XXX-comment: The original IR InstCombiner would change our and instruction
-  // to a select and then the back end optimize the condition out.  We attach a
-  // flag to instructions and set it here to inform the InstCombiner to not to
-  // touch this and instruction at all.
-  Value* OrAddr = Builder.CreateOr(AndDepVal, PtrToIntCast);
-  Value* NewAddr = Builder.CreateIntToPtr(OrAddr, Address->getType());
-
-  DEBUG(dbgs() << "[taintStoreAddress]\n"
-               << "Original store: " << *SI << '\n');
-  SI->setOperand(1, NewAddr);
-
-  // Debug output.
-  DEBUG(dbgs() << "\tTargetIntegerType: " << *TargetIntegerType << '\n'
-               << "\tCast dependence value to integer: " << *CastDepToInt
-               << '\n'
-               << "\tCast address to integer: " << *PtrToIntCast << '\n'
-               << "\tAnd dependence value: " << *AndDepVal << '\n'
-               << "\tOr address: " << *OrAddr << '\n'
-               << "\tCast or instruction to address: " << *NewAddr << "\n\n");
-
-  return true;
-}
-
-// Looks for the previous store in the if block --- 'BrBB', which makes the
-// speculative store 'StoreToHoist' safe.
-Value* getSpeculativeStoreInPrevBB(StoreInst* StoreToHoist, BasicBlock* BrBB) {
-  assert(StoreToHoist && "StoreToHoist must be a real store");
-
-  Value* StorePtr = StoreToHoist->getPointerOperand();
-
-  // Look for a store to the same pointer in BrBB.
-  for (BasicBlock::reverse_iterator RI = BrBB->rbegin(), RE = BrBB->rend();
-       RI != RE; ++RI) {
-    Instruction* CurI = &*RI;
-
-    StoreInst* SI = dyn_cast<StoreInst>(CurI);
-    // Found the previous store make sure it stores to the same location.
-    // XXX-update: If the previous store's original untainted address are the
-    // same as 'StorePtr', we are also good to hoist the store.
-    if (SI && (SI->getPointerOperand() == StorePtr ||
-               GetUntaintedAddress(SI->getPointerOperand()) == StorePtr)) {
-      // Found the previous store, return its value operand.
-      return SI;
-    }
-  }
-
-  assert(false &&
-         "We should not reach here since this store is safe to speculate");
-}
-
-// XXX-comment: Returns true if it changes the code, false otherwise (the branch
-// condition already depends on 'DepVal'.
-bool taintConditionalBranch(BranchInst* BI, Value* DepVal) {
-  assert(BI->isConditional());
-  auto* Cond = BI->getOperand(0);
-  if (dependenceSetInclusion(Cond, DepVal)) {
-    // The dependence/ordering is self-evident.
-    return false;
-  }
-
-  IRBuilder<true, NoFolder> Builder(BI);
-  auto* AndDep =
-      Builder.CreateAnd(DepVal, ConstantInt::get(DepVal->getType(), 0));
-  auto* TruncAndDep =
-      Builder.CreateTrunc(AndDep, IntegerType::get(DepVal->getContext(), 1));
-  auto* OrCond = Builder.CreateOr(TruncAndDep, Cond);
-  BI->setOperand(0, OrCond);
-
-  // Debug output.
-  DEBUG(dbgs() << "\tTainted branch condition:\n" << *BI->getParent());
-
-  return true;
-}
-
-// XXX-update: For a relaxed load 'LI', find the first immediate atomic store or
-// the first conditional branch. Returns nullptr if there's no such immediately
-// following store/branch instructions, which we can only enforce the load with
-// 'acquire'.
-Instruction* findFirstStoreCondBranchInst(LoadInst* LI) {
-  // In some situations, relaxed loads can be left as is:
-  // 1. The relaxed load is used to calculate the address of the immediate
-  // following store;
-  // 2. The relaxed load is used as a condition in the immediate following
-  // condition, and there are no stores in between. This is actually quite
-  // common. E.g.,
-  // int r1 = x.load(relaxed);
-  // if (r1 != 0) {
-  //   y.store(1, relaxed);
-  // }
-  // However, in this function, we don't deal with them directly. Instead, we
-  // just find the immediate following store/condition branch and return it.
-
-  auto* BB = LI->getParent();
-  auto BE = BB->end();
-  auto BBI = BasicBlock::iterator(LI);
-  BBI++;
-  while (true) {
-    for (; BBI != BE; BBI++) {
-      auto* Inst = dyn_cast<Instruction>(&*BBI);
-      if (Inst == nullptr) {
-        continue;
-      }
-      if (Inst->getOpcode() == Instruction::Store) {
-        return Inst;
-      } else if (Inst->getOpcode() == Instruction::Br) {
-        auto* BrInst = dyn_cast<BranchInst>(Inst);
-        if (BrInst->isConditional()) {
-          return Inst;
-        } else {
-          // Reinitialize iterators with the destination of the unconditional
-          // branch.
-          BB = BrInst->getSuccessor(0);
-          BBI = BB->begin();
-          BE = BB->end();
-          break;
-        }
-      }
-    }
-    if (BBI == BE) {
-      return nullptr;
-    }
-  }
-}
-
-// XXX-comment: Returns whether the code has been changed.
-bool taintMonotonicLoads(const SmallVector<LoadInst*, 1>& MonotonicLoadInsts) {
-  bool Changed = false;
-  for (auto* LI : MonotonicLoadInsts) {
-    auto* FirstInst = findFirstStoreCondBranchInst(LI);
-    if (FirstInst == nullptr) {
-      // We don't seem to be able to taint a following store/conditional branch
-      // instruction. Simply make it acquire.
-      DEBUG(dbgs() << "[RelaxedLoad]: Transformed to acquire load\n"
-                   << *LI << "\n");
-      LI->setOrdering(Acquire);
-      Changed = true;
-      continue;
-    }
-    // Taint 'FirstInst', which could be a store or a condition branch
-    // instruction.
-    if (FirstInst->getOpcode() == Instruction::Store) {
-      Changed |= taintStoreAddress(dyn_cast<StoreInst>(FirstInst), LI);
-    } else if (FirstInst->getOpcode() == Instruction::Br) {
-      Changed |= taintConditionalBranch(dyn_cast<BranchInst>(FirstInst), LI);
-    } else {
-      assert(false && "findFirstStoreCondBranchInst() should return a "
-                    "store/condition branch instruction");
-    }
-  }
-  return Changed;
-}
-
-/**** Implementations of public methods for dependence tainting ****/
-Value* GetUntaintedAddress(Value* CurrentAddress) {
-  auto* OrAddress = getOrAddress(CurrentAddress);
-  if (OrAddress == nullptr) {
-    // Is it tainted by a select instruction?
-    auto* Inst = dyn_cast<Instruction>(CurrentAddress);
-    if (nullptr != Inst && Inst->getOpcode() == Instruction::Select) {
-      // A selection instruction.
-      if (Inst->getOperand(1) == Inst->getOperand(2)) {
-        return Inst->getOperand(1);
-      }
-    }
-
-    return CurrentAddress;
-  }
-  Value* ActualAddress = nullptr;
-
-  auto* CastToInt = dyn_cast<Instruction>(OrAddress->getOperand(1));
-  if (CastToInt && CastToInt->getOpcode() == Instruction::PtrToInt) {
-    return CastToInt->getOperand(0);
-  } else {
-    // This should be a IntToPtr constant expression.
-    ConstantExpr* PtrToIntExpr =
-        dyn_cast<ConstantExpr>(OrAddress->getOperand(1));
-    if (PtrToIntExpr && PtrToIntExpr->getOpcode() == Instruction::PtrToInt) {
-      return PtrToIntExpr->getOperand(0);
-    }
-  }
-
-  // Looks like it's not been dependence-tainted. Returns itself.
-  return CurrentAddress;
-}
-
-MemoryLocation GetUntaintedMemoryLocation(StoreInst* SI) {
-  AAMDNodes AATags;
-  SI->getAAMetadata(AATags);
-  const auto& DL = SI->getModule()->getDataLayout();
-  const auto* OriginalAddr = GetUntaintedAddress(SI->getPointerOperand());
-  DEBUG(if (OriginalAddr != SI->getPointerOperand()) {
-    dbgs() << "[GetUntaintedMemoryLocation]\n"
-           << "Storing address: " << *SI->getPointerOperand()
-           << "\nUntainted address: " << *OriginalAddr << "\n";
-  });
-  return MemoryLocation(OriginalAddr,
-                        DL.getTypeStoreSize(SI->getValueOperand()->getType()),
-                        AATags);
-}
-
-bool TaintDependenceToStore(StoreInst* SI, Value* DepVal) {
-  if (dependenceSetInclusion(SI, DepVal)) {
-    return false;
-  }
-
-  bool tainted = taintStoreAddress(SI, DepVal);
-  assert(tainted);
-  return tainted;
-}
-
-bool TaintDependenceToStoreAddress(StoreInst* SI, Value* DepVal) {
-  if (dependenceSetInclusion(SI->getPointerOperand(), DepVal)) {
-    return false;
-  }
-
-  bool tainted = taintStoreAddress(SI, DepVal);
-  assert(tainted);
-  return tainted;
-}
-
-bool CompressTaintedStore(BasicBlock* BB) {
-  // This function looks for windows of adajcent stores in 'BB' that satisfy the
-  // following condition (and then do optimization):
-  // *Addr(d1) = v1, d1 is a condition and is the only dependence the store's
-  //                 address depends on && Dep(v1) includes Dep(d1);
-  // *Addr(d2) = v2, d2 is a condition and is the only dependnece the store's
-  //                 address depends on && Dep(v2) includes Dep(d2) &&
-  //                 Dep(d2) includes Dep(d1);
-  // ...
-  // *Addr(dN) = vN, dN is a condition and is the only dependence the store's
-  //                 address depends on && Dep(dN) includes Dep(d"N-1").
-  //
-  // As a result, Dep(dN) includes [Dep(d1) V ... V Dep(d"N-1")], so we can
-  // safely transform the above to the following. In between these stores, we
-  // can omit untainted stores to the same address 'Addr' since they internally
-  // have dependence on the previous stores on the same address.
-  // =>
-  // *Addr = v1
-  // *Addr = v2
-  // *Addr(d3) = v3
-  for (auto BI = BB->begin(), BE = BB->end(); BI != BE; BI++) {
-    // Look for the first store in such a window of adajacent stores.
-    auto* FirstSI = dyn_cast<StoreInst>(&*BI);
-    if (!FirstSI) {
-      continue;
-    }
-
-    // The first store in the window must be tainted.
-    auto* UntaintedAddress = GetUntaintedAddress(FirstSI->getPointerOperand());
-    if (UntaintedAddress == FirstSI->getPointerOperand()) {
-      continue;
-    }
-
-    // The first store's address must directly depend on and only depend on a
-    // condition.
-    auto* FirstSIDepCond = getConditionDependence(FirstSI->getPointerOperand());
-    if (nullptr == FirstSIDepCond) {
-      continue;
-    }
-
-    // Dep(first store's storing value) includes Dep(tainted dependence).
-    if (!dependenceSetInclusion(FirstSI->getValueOperand(), FirstSIDepCond)) {
-      continue;
-    }
-
-    // Look for subsequent stores to the same address that satisfy the condition
-    // of "compressing the dependence".
-    SmallVector<StoreInst*, 8> AdajacentStores;
-    AdajacentStores.push_back(FirstSI);
-    auto BII = BasicBlock::iterator(FirstSI);
-    for (BII++; BII != BE; BII++) {
-      auto* CurrSI = dyn_cast<StoreInst>(&*BII);
-      if (!CurrSI) {
-        if (BII->mayHaveSideEffects()) {
-          // Be conservative. Instructions with side effects are similar to
-          // stores.
-          break;
-        }
-        continue;
-      }
-
-      auto* OrigAddress = GetUntaintedAddress(CurrSI->getPointerOperand());
-      auto* CurrSIDepCond = getConditionDependence(CurrSI->getPointerOperand());
-      // All other stores must satisfy either:
-      // A. 'CurrSI' is an untainted store to the same address, or
-      // B. the combination of the following 5 subconditions:
-      // 1. Tainted;
-      // 2. Untainted address is the same as the group's address;
-      // 3. The address is tainted with a sole value which is a condition;
-      // 4. The storing value depends on the condition in 3.
-      // 5. The condition in 3 depends on the previous stores dependence
-      // condition.
-
-      // Condition A. Should ignore this store directly.
-      if (OrigAddress == CurrSI->getPointerOperand() &&
-          OrigAddress == UntaintedAddress) {
-        continue;
-      }
-      // Check condition B.
-      Value* Cond = nullptr;
-      if (OrigAddress == CurrSI->getPointerOperand() ||
-          OrigAddress != UntaintedAddress || CurrSIDepCond == nullptr ||
-          !dependenceSetInclusion(CurrSI->getValueOperand(), CurrSIDepCond)) {
-        // Check condition 1, 2, 3 & 4.
-        break;
-      }
-
-      // Check condition 5.
-      StoreInst* PrevSI = AdajacentStores[AdajacentStores.size() - 1];
-      auto* PrevSIDepCond = getConditionDependence(PrevSI->getPointerOperand());
-      assert(PrevSIDepCond &&
-             "Store in the group must already depend on a condtion");
-      if (!dependenceSetInclusion(CurrSIDepCond, PrevSIDepCond)) {
-        break;
-      }
-
-      AdajacentStores.push_back(CurrSI);
-    }
-
-    if (AdajacentStores.size() == 1) {
-      // The outer loop should keep looking from the next store.
-      continue;
-    }
-
-    // Now we have such a group of tainted stores to the same address.
-    DEBUG(dbgs() << "[CompressTaintedStore]\n");
-    DEBUG(dbgs() << "Original BB\n");
-    DEBUG(dbgs() << *BB << '\n');
-    auto* LastSI = AdajacentStores[AdajacentStores.size() - 1];
-    for (int i = 0; i < AdajacentStores.size() - 1; ++i) {
-      auto* SI = AdajacentStores[i];
-
-      // Use the original address for stores before the last one.
-      SI->setOperand(1, UntaintedAddress);
-
-      DEBUG(dbgs() << "Store address has been reversed: " << *SI << '\n';);
-    }
-    // XXX-comment: Try to make the last store use fewer registers.
-    // If LastSI's storing value is a select based on the condition with which
-    // its address is tainted, transform the tainted address to a select
-    // instruction, as follows:
-    // r1 = Select Cond ? A : B
-    // r2 = Cond & 0
-    // r3 = Addr | r2
-    // *r3 = r1
-    // ==>
-    // r1 = Select Cond ? A : B
-    // r2 = Select Cond ? Addr : Addr
-    // *r2 = r1
-    // The idea is that both Select instructions depend on the same condition,
-    // so hopefully the backend can generate two cmov instructions for them (and
-    // this saves the number of registers needed).
-    auto* LastSIDep = getConditionDependence(LastSI->getPointerOperand());
-    auto* LastSIValue = dyn_cast<Instruction>(LastSI->getValueOperand());
-    if (LastSIValue && LastSIValue->getOpcode() == Instruction::Select &&
-        LastSIValue->getOperand(0) == LastSIDep) {
-      // XXX-comment: Maybe it's better for us to just leave it as an and/or
-      // dependence pattern.
-      //      /*
-      IRBuilder<true, NoFolder> Builder(LastSI);
-      auto* Address =
-          Builder.CreateSelect(LastSIDep, UntaintedAddress, UntaintedAddress);
-      LastSI->setOperand(1, Address);
-      DEBUG(dbgs() << "The last store becomes :" << *LastSI << "\n\n";);
-      //      */
-    }
-  }
-
-  return true;
-}
-
-bool PassDependenceToStore(Value* OldAddress, StoreInst* NewStore) {
-  Value* OldDep = getDependence(OldAddress);
-  // Return false when there's no dependence to pass from the OldAddress.
-  if (!OldDep) {
-    return false;
-  }
-
-  // No need to pass the dependence to NewStore's address if it already depends
-  // on whatever 'OldAddress' depends on.
-  if (StoreAddressDependOnValue(NewStore, OldDep)) {
-    return false;
-  }
-  return taintStoreAddress(NewStore, OldAddress);
-}
-
-SmallSet<Value*, 8> FindDependence(Value* Val) {
-  SmallSet<Value*, 8> DepSet;
-  recursivelyFindDependence(&DepSet, Val, true /*Only insert leaf nodes*/);
-  return DepSet;
-}
-
-bool StoreAddressDependOnValue(StoreInst* SI, Value* DepVal) {
-  return dependenceSetInclusion(SI->getPointerOperand(), DepVal);
-}
-
-bool StoreDependOnValue(StoreInst* SI, Value* Dep) {
-  return dependenceSetInclusion(SI, Dep);
-}
-
-} // namespace
-
-
 bool AtomicExpand::runOnFunction(Function &F) {
   if (!TM || !TM->getSubtargetImpl(F)->enableAtomicExpand())
     return false;
@@ -916,7 +159,7 @@ bool AtomicExpand::runOnFunction(Function &F) {
     if (TLI->getInsertFencesForAtomic()) {
       if (LI && isAtLeastAcquire(LI->getOrdering())) {
         FenceOrdering = LI->getOrdering();
-        LI->setOrdering(Monotonic);
+//        AddFakeConditionalBranch(
         IsStore = false;
         IsLoad = true;
       } else if (SI && isAtLeastRelease(SI->getOrdering())) {
@@ -985,8 +228,6 @@ bool AtomicExpand::runOnFunction(Function &F) {
     }
   }
 
-  MadeChange |= taintMonotonicLoads(MonotonicLoadInsts);
-
   return MadeChange;
 }