Revert " Renable r314928"

This reverts commit 4cdc9da.

The compile-time initially observed is still here even after the fix in
5214dbb.

rdar://58878122

Author: francisvm

llvm/lib/Transforms/InstCombine/InstCombineInternal.h

@@ -827,11 +827,6 @@ class LLVM_LIBRARY_VISIBILITY InstCombiner
   Instruction *FoldPHIArgLoadIntoPHI(PHINode &PN);
   Instruction *FoldPHIArgZextsIntoPHI(PHINode &PN);
 
-  /// If an integer typed PHI has only one use which is an IntToPtr operation,
-  /// replace the PHI with an existing pointer typed PHI if it exists. Otherwise
-  /// insert a new pointer typed PHI and replace the original one.
-  Instruction *FoldIntegerTypedPHI(PHINode &PN);
-
   /// Helper function for FoldPHIArgXIntoPHI() to set debug location for the
   /// folded operation.
   void PHIArgMergedDebugLoc(Instruction *Inst, PHINode &PN);

llvm/lib/Transforms/InstCombine/InstCombinePHI.cpp

@@ -42,242 +42,6 @@ void InstCombiner::PHIArgMergedDebugLoc(Instruction *Inst, PHINode &PN) {
   }
 }
 
-// Replace Integer typed PHI PN if the PHI's value is used as a pointer value.
-// If there is an existing pointer typed PHI that produces the same value as PN,
-// replace PN and the IntToPtr operation with it. Otherwise, synthesize a new
-// PHI node:
-//
-// Case-1:
-// bb1:
-//     int_init = PtrToInt(ptr_init)
-//     br label %bb2
-// bb2:
-//    int_val = PHI([int_init, %bb1], [int_val_inc, %bb2]
-//    ptr_val = PHI([ptr_init, %bb1], [ptr_val_inc, %bb2]
-//    ptr_val2 = IntToPtr(int_val)
-//    ...
-//    use(ptr_val2)
-//    ptr_val_inc = ...
-//    inc_val_inc = PtrToInt(ptr_val_inc)
-//
-// ==>
-// bb1:
-//     br label %bb2
-// bb2:
-//    ptr_val = PHI([ptr_init, %bb1], [ptr_val_inc, %bb2]
-//    ...
-//    use(ptr_val)
-//    ptr_val_inc = ...
-//
-// Case-2:
-// bb1:
-//    int_ptr = BitCast(ptr_ptr)
-//    int_init = Load(int_ptr)
-//    br label %bb2
-// bb2:
-//    int_val = PHI([int_init, %bb1], [int_val_inc, %bb2]
-//    ptr_val2 = IntToPtr(int_val)
-//    ...
-//    use(ptr_val2)
-//    ptr_val_inc = ...
-//    inc_val_inc = PtrToInt(ptr_val_inc)
-// ==>
-// bb1:
-//    ptr_init = Load(ptr_ptr)
-//    br label %bb2
-// bb2:
-//    ptr_val = PHI([ptr_init, %bb1], [ptr_val_inc, %bb2]
-//    ...
-//    use(ptr_val)
-//    ptr_val_inc = ...
-//    ...
-//
-Instruction *InstCombiner::FoldIntegerTypedPHI(PHINode &PN) {
-  if (!PN.getType()->isIntegerTy())
-    return nullptr;
-  if (!PN.hasOneUse())
-    return nullptr;
-
-  auto *IntToPtr = dyn_cast<IntToPtrInst>(PN.user_back());
-  if (!IntToPtr)
-    return nullptr;
-
-  // Check if the pointer is actually used as pointer:
-  auto HasPointerUse = [](Instruction *IIP) {
-    for (User *U : IIP->users()) {
-      Value *Ptr = nullptr;
-      if (LoadInst *LoadI = dyn_cast<LoadInst>(U)) {
-        Ptr = LoadI->getPointerOperand();
-      } else if (StoreInst *SI = dyn_cast<StoreInst>(U)) {
-        Ptr = SI->getPointerOperand();
-      } else if (GetElementPtrInst *GI = dyn_cast<GetElementPtrInst>(U)) {
-        Ptr = GI->getPointerOperand();
-      }
-
-      if (Ptr && Ptr == IIP)
-        return true;
-    }
-    return false;
-  };
-
-  if (!HasPointerUse(IntToPtr))
-    return nullptr;
-
-  if (DL.getPointerSizeInBits(IntToPtr->getAddressSpace()) !=
-      DL.getTypeSizeInBits(IntToPtr->getOperand(0)->getType()))
-    return nullptr;
-
-  SmallVector<Value *, 4> AvailablePtrVals;
-  for (unsigned i = 0; i != PN.getNumIncomingValues(); ++i) {
-    Value *Arg = PN.getIncomingValue(i);
-
-    // First look backward:
-    if (auto *PI = dyn_cast<PtrToIntInst>(Arg)) {
-      AvailablePtrVals.emplace_back(PI->getOperand(0));
-      continue;
-    }
-
-    // Next look forward:
-    Value *ArgIntToPtr = nullptr;
-    for (User *U : Arg->users()) {
-      if (isa<IntToPtrInst>(U) && U->getType() == IntToPtr->getType() &&
-          (DT.dominates(cast<Instruction>(U), PN.getIncomingBlock(i)) ||
-           cast<Instruction>(U)->getParent() == PN.getIncomingBlock(i))) {
-        ArgIntToPtr = U;
-        break;
-      }
-    }
-
-    if (ArgIntToPtr) {
-      AvailablePtrVals.emplace_back(ArgIntToPtr);
-      continue;
-    }
-
-    // If Arg is defined by a PHI, allow it. This will also create
-    // more opportunities iteratively.
-    if (isa<PHINode>(Arg)) {
-      AvailablePtrVals.emplace_back(Arg);
-      continue;
-    }
-
-    // For a single use integer load:
-    auto *LoadI = dyn_cast<LoadInst>(Arg);
-    if (!LoadI)
-      return nullptr;
-
-    if (!LoadI->hasOneUse())
-      return nullptr;
-
-    // Push the integer typed Load instruction into the available
-    // value set, and fix it up later when the pointer typed PHI
-    // is synthesized.
-    AvailablePtrVals.emplace_back(LoadI);
-  }
-
-  // Now search for a matching PHI
-  auto *BB = PN.getParent();
-  assert(AvailablePtrVals.size() == PN.getNumIncomingValues() &&
-         "Not enough available ptr typed incoming values");
-  PHINode *MatchingPtrPHI = nullptr;
-  unsigned NumPhis = 0;
-  for (auto II = BB->begin(), EI = BasicBlock::iterator(BB->getFirstNonPHI());
-       II != EI; II++, NumPhis++) {
-    // FIXME: consider handling this in AggressiveInstCombine
-    if (NumPhis > MaxNumPhis)
-      return nullptr;
-    PHINode *PtrPHI = dyn_cast<PHINode>(II);
-    if (!PtrPHI || PtrPHI == &PN || PtrPHI->getType() != IntToPtr->getType())
-      continue;
-    MatchingPtrPHI = PtrPHI;
-    for (unsigned i = 0; i != PtrPHI->getNumIncomingValues(); ++i) {
-      if (AvailablePtrVals[i] !=
-          PtrPHI->getIncomingValueForBlock(PN.getIncomingBlock(i))) {
-        MatchingPtrPHI = nullptr;
-        break;
-      }
-    }
-
-    if (MatchingPtrPHI)
-      break;
-  }
-
-  if (MatchingPtrPHI) {
-    assert(MatchingPtrPHI->getType() == IntToPtr->getType() &&
-           "Phi's Type does not match with IntToPtr");
-    // The PtrToCast + IntToPtr will be simplified later
-    return CastInst::CreateBitOrPointerCast(MatchingPtrPHI,
-                                            IntToPtr->getOperand(0)->getType());
-  }
-
-  // If it requires a conversion for every PHI operand, do not do it.
-  if (all_of(AvailablePtrVals, [&](Value *V) {
-        return (V->getType() != IntToPtr->getType()) || isa<IntToPtrInst>(V);
-      }))
-    return nullptr;
-
-  // If any of the operand that requires casting is a terminator
-  // instruction, do not do it.
-  if (any_of(AvailablePtrVals, [&](Value *V) {
-        if (V->getType() == IntToPtr->getType())
-          return false;
-
-        auto *Inst = dyn_cast<Instruction>(V);
-        return Inst && Inst->isTerminator();
-      }))
-    return nullptr;
-
-  PHINode *NewPtrPHI = PHINode::Create(
-      IntToPtr->getType(), PN.getNumIncomingValues(), PN.getName() + ".ptr");
-
-  InsertNewInstBefore(NewPtrPHI, PN);
-  SmallDenseMap<Value *, Instruction *> Casts;
-  for (unsigned i = 0; i != PN.getNumIncomingValues(); ++i) {
-    auto *IncomingBB = PN.getIncomingBlock(i);
-    auto *IncomingVal = AvailablePtrVals[i];
-
-    if (IncomingVal->getType() == IntToPtr->getType()) {
-      NewPtrPHI->addIncoming(IncomingVal, IncomingBB);
-      continue;
-    }
-
-#ifndef NDEBUG
-    LoadInst *LoadI = dyn_cast<LoadInst>(IncomingVal);
-    assert((isa<PHINode>(IncomingVal) ||
-            IncomingVal->getType()->isPointerTy() ||
-            (LoadI && LoadI->hasOneUse())) &&
-           "Can not replace LoadInst with multiple uses");
-#endif
-    // Need to insert a BitCast.
-    // For an integer Load instruction with a single use, the load + IntToPtr
-    // cast will be simplified into a pointer load:
-    // %v = load i64, i64* %a.ip, align 8
-    // %v.cast = inttoptr i64 %v to float **
-    // ==>
-    // %v.ptrp = bitcast i64 * %a.ip to float **
-    // %v.cast = load float *, float ** %v.ptrp, align 8
-    Instruction *&CI = Casts[IncomingVal];
-    if (!CI) {
-      CI = CastInst::CreateBitOrPointerCast(IncomingVal, IntToPtr->getType(),
-                                            IncomingVal->getName() + ".ptr");
-      if (auto *IncomingI = dyn_cast<Instruction>(IncomingVal)) {
-        BasicBlock::iterator InsertPos(IncomingI);
-        InsertPos++;
-        if (isa<PHINode>(IncomingI))
-          InsertPos = IncomingI->getParent()->getFirstInsertionPt();
-        InsertNewInstBefore(CI, *InsertPos);
-      } else {
-        auto *InsertBB = &IncomingBB->getParent()->getEntryBlock();
-        InsertNewInstBefore(CI, *InsertBB->getFirstInsertionPt());
-      }
-    }
-    NewPtrPHI->addIncoming(CI, IncomingBB);
-  }
-
-  // The PtrToCast + IntToPtr will be simplified later
-  return CastInst::CreateBitOrPointerCast(NewPtrPHI,
-                                          IntToPtr->getOperand(0)->getType());
-}
-
 /// If we have something like phi [add (a,b), add(a,c)] and if a/b/c and the
 /// adds all have a single use, turn this into a phi and a single binop.
 Instruction *InstCombiner::FoldPHIArgBinOpIntoPHI(PHINode &PN) {
@@ -1142,9 +906,6 @@ Instruction *InstCombiner::visitPHINode(PHINode &PN) {
   // this PHI only has a single use (a PHI), and if that PHI only has one use (a
   // PHI)... break the cycle.
   if (PN.hasOneUse()) {
-    if (Instruction *Result = FoldIntegerTypedPHI(PN))
-      return Result;
-
     Instruction *PHIUser = cast<Instruction>(PN.user_back());
     if (PHINode *PU = dyn_cast<PHINode>(PHIUser)) {
       SmallPtrSet<PHINode*, 16> PotentiallyDeadPHIs;