Revert r252249 (and r252255, r252258), "[WinEH] Clone funclets with multiple parents"

It behaved flaky due to iterating pointer key values on std::set and std::map.

llvm-svn: 252279

1 files changed, 14 insertions, 977 deletions

diff --git a/llvm/lib/CodeGen/WinEHPrepare.cpp b/llvm/lib/CodeGen/WinEHPrepare.cpp
index 7b0dbd0c395..ca69d321f3b 100644
--- a/llvm/lib/CodeGen/WinEHPrepare.cpp
+++ b/llvm/lib/CodeGen/WinEHPrepare.cpp
@@ -74,20 +74,6 @@ private:
                          SmallVectorImpl<BasicBlock *> &EntryBlocks);
   void replaceTerminatePadWithCleanup(Function &F);
   void colorFunclets(Function &F, SmallVectorImpl<BasicBlock *> &EntryBlocks);
-  void resolveFuncletAncestry(Function &F,
-                              SmallVectorImpl<BasicBlock *> &EntryBlocks);
-  void resolveFuncletAncestryForPath(
-      Function &F, SmallVectorImpl<BasicBlock *> &FuncletPath,
-      std::map<BasicBlock *, BasicBlock *> &IdentityMap);
-  void makeFuncletEdgeUnreachable(BasicBlock *Parent, BasicBlock *Child);
-  BasicBlock *cloneFuncletForParent(Function &F, BasicBlock *FuncletEntry,
-                                    BasicBlock *Parent);
-  void updateTerminatorsAfterFuncletClone(
-      Function &F, BasicBlock *OrigFunclet, BasicBlock *CloneFunclet,
-      BasicBlock *OrigBlock, BasicBlock *CloneBlock, BasicBlock *CloneParent,
-      ValueToValueMapTy &VMap,
-      std::map<BasicBlock *, BasicBlock *> &Orig2Clone);
-
   void demotePHIsOnFunclets(Function &F);
   void demoteUsesBetweenFunclets(Function &F);
   void demoteArgumentUses(Function &F);
@@ -102,18 +88,7 @@ private:
 
   std::map<BasicBlock *, std::set<BasicBlock *>> BlockColors;
   std::map<BasicBlock *, std::set<BasicBlock *>> FuncletBlocks;
-  std::map<BasicBlock *, std::vector<BasicBlock *>> FuncletChildren;
-  std::map<BasicBlock *, std::vector<BasicBlock *>> FuncletParents;
-
-  // This is a flag that indicates an uncommon situation where we need to
-  // clone funclets has been detected.
-  bool FuncletCloningRequired = false;
-  // When a funclet with multiple parents contains a catchret, the block to
-  // which it returns will be cloned so that there is a copy in each parent
-  // but one of the copies will not be properly linked to the catchret and
-  // in most cases will have no predecessors.  This double map allows us
-  // to find these cloned blocks when we clone the child funclet.
-  std::map<BasicBlock *, std::map<BasicBlock *, BasicBlock*>> EstrangedBlocks;
+  std::map<BasicBlock *, std::set<BasicBlock *>> FuncletChildren;
 };
 
 } // end anonymous namespace
@@ -584,7 +559,8 @@ void WinEHPrepare::replaceTerminatePadWithCleanup(Function &F) {
 static void
 colorFunclets(Function &F, SmallVectorImpl<BasicBlock *> &EntryBlocks,
               std::map<BasicBlock *, std::set<BasicBlock *>> &BlockColors,
-              std::map<BasicBlock *, std::set<BasicBlock *>> &FuncletBlocks) {
+              std::map<BasicBlock *, std::set<BasicBlock *>> &FuncletBlocks,
+              std::map<BasicBlock *, std::set<BasicBlock *>> &FuncletChildren) {
   SmallVector<std::pair<BasicBlock *, BasicBlock *>, 16> Worklist;
   BasicBlock *EntryBlock = &F.getEntryBlock();
 
@@ -601,18 +577,12 @@ colorFunclets(Function &F, SmallVectorImpl<BasicBlock *> &EntryBlocks,
   // are as defined above.  A post-pass fixes up the block color map to reflect
   // the same sense of "color" for funclet entries as for other blocks.
 
-  DEBUG_WITH_TYPE("winehprepare-coloring", dbgs() << "\nColoring funclets for "
-                                                  << F.getName() << "\n");
-
   Worklist.push_back({EntryBlock, EntryBlock});
 
   while (!Worklist.empty()) {
     BasicBlock *Visiting;
     BasicBlock *Color;
     std::tie(Visiting, Color) = Worklist.pop_back_val();
-    DEBUG_WITH_TYPE("winehprepare-coloring",
-                    dbgs() << "Visiting " << Visiting->getName() << ", "
-                           << Color->getName() << "\n");
     Instruction *VisitingHead = Visiting->getFirstNonPHI();
     if (VisitingHead->isEHPad() && !isa<CatchEndPadInst>(VisitingHead) &&
         !isa<CleanupEndPadInst>(VisitingHead)) {
@@ -630,13 +600,8 @@ colorFunclets(Function &F, SmallVectorImpl<BasicBlock *> &EntryBlocks,
         if (auto *Exit = dyn_cast<TerminatorInst>(U)) {
           for (BasicBlock *Succ : successors(Exit->getParent()))
             if (!isa<CatchEndPadInst>(*Succ->getFirstNonPHI()))
-              if (BlockColors[Succ].insert(Color).second) {
-                DEBUG_WITH_TYPE("winehprepare-coloring",
-                                dbgs() << "  Assigned color \'"
-                                       << Color->getName() << "\' to block \'"
-                                       << Succ->getName() << "\'.\n");
+              if (BlockColors[Succ].insert(Color).second)
                 Worklist.push_back({Succ, Color});
-              }
         }
       }
       // Handle CatchPad specially since its successors need different colors.
@@ -645,18 +610,10 @@ colorFunclets(Function &F, SmallVectorImpl<BasicBlock *> &EntryBlocks,
         // visit the unwind successor with the color of the parent.
         BasicBlock *NormalSucc = CatchPad->getNormalDest();
         if (BlockColors[NormalSucc].insert(Visiting).second) {
-          DEBUG_WITH_TYPE("winehprepare-coloring",
-                          dbgs() << "  Assigned color \'" << Visiting->getName()
-                                 << "\' to block \'" << NormalSucc->getName()
-                                 << "\'.\n");
           Worklist.push_back({NormalSucc, Visiting});
         }
         BasicBlock *UnwindSucc = CatchPad->getUnwindDest();
         if (BlockColors[UnwindSucc].insert(Color).second) {
-          DEBUG_WITH_TYPE("winehprepare-coloring",
-                          dbgs() << "  Assigned color \'" << Color->getName()
-                                 << "\' to block \'" << UnwindSucc->getName()
-                                 << "\'.\n");
           Worklist.push_back({UnwindSucc, Color});
         }
         continue;
@@ -688,806 +645,10 @@ colorFunclets(Function &F, SmallVectorImpl<BasicBlock *> &EntryBlocks,
         continue;
       }
       if (BlockColors[Succ].insert(Color).second) {
-        DEBUG_WITH_TYPE("winehprepare-coloring",
-                        dbgs() << "  Assigned color \'" << Color->getName()
-                               << "\' to block \'" << Succ->getName()
-                               << "\'.\n");
         Worklist.push_back({Succ, Color});
       }
     }
   }
-}
-
-static BasicBlock *getEndPadForCatch(CatchPadInst *Catch) {
-  // The catch may have sibling catches.  Follow the unwind chain until we get
-  // to the catchendpad.
-  BasicBlock *NextUnwindDest = Catch->getUnwindDest();
-  auto *UnwindTerminator = NextUnwindDest->getTerminator();
-  while (auto *NextCatch = dyn_cast<CatchPadInst>(UnwindTerminator)) {
-    NextUnwindDest = NextCatch->getUnwindDest();
-    UnwindTerminator = NextUnwindDest->getTerminator();
-  }
-  // The last catch in the chain must unwind to a catchendpad.
-  assert(isa<CatchEndPadInst>(UnwindTerminator));
-  return NextUnwindDest;
-}
-
-static void updateClonedEHPadUnwindToParent(
-    BasicBlock *UnwindDest, BasicBlock *OrigBlock, BasicBlock *CloneBlock,
-    std::vector<BasicBlock *> &OrigParents, BasicBlock *CloneParent) {
-  auto updateUnwindTerminator = [](BasicBlock *BB) {
-    auto *Terminator = BB->getTerminator();
-    if (isa<CatchEndPadInst>(Terminator) ||
-        isa<CleanupEndPadInst>(Terminator)) {
-      removeUnwindEdge(BB);
-    } else {
-      // If the block we're updating has a cleanupendpad or cleanupret
-      // terminator, we just want to replace that terminator with an
-      // unreachable instruction.
-      assert(isa<CleanupEndPadInst>(Terminator) ||
-             isa<CleanupReturnInst>(Terminator));
-      // Loop over all of the successors, removing the block's entry from any
-      // PHI nodes.
-      for (succ_iterator SI = succ_begin(BB), SE = succ_end(BB); SI != SE; ++SI)
-        (*SI)->removePredecessor(BB);
-      // Remove the terminator and replace it with an unreachable instruction.
-      BB->getTerminator()->eraseFromParent();
-      new UnreachableInst(BB->getContext(), BB);
-    }
-  };
-
-  assert(UnwindDest->isEHPad());
-  // There are many places to which this EH terminator can unwind and each has
-  // slightly different rules for whether or not it fits with the given
-  // location.
-  auto *EHPadInst = UnwindDest->getFirstNonPHI();
-  if (isa<CatchEndPadInst>(EHPadInst)) {
-    auto *CloneParentCatch =
-        dyn_cast<CatchPadInst>(CloneParent->getFirstNonPHI());
-    if (!CloneParentCatch ||
-        getEndPadForCatch(CloneParentCatch) != UnwindDest) {
-      DEBUG_WITH_TYPE(
-          "winehprepare-coloring",
-          dbgs() << "      removing unwind destination of clone block \'"
-                 << CloneBlock->getName() << "\'.\n");
-      updateUnwindTerminator(CloneBlock);
-    }
-    // It's possible that the catch end pad is a legal match for both the clone
-    // and the original, so they must be checked separately.  If the original
-    // funclet will still have multiple parents after the current clone parent
-    // is removed, we'll leave its unwind terminator until later.
-    assert(OrigParents.size() >= 2);
-    if (OrigParents.size() != 2)
-      return;
-
-    // If the original funclet will have a single parent after the clone parent
-    // is removed, check that parent's unwind destination.
-    assert(OrigParents.front() == CloneParent ||
-           OrigParents.back() == CloneParent);
-    BasicBlock *OrigParent;
-    if (OrigParents.front() == CloneParent)
-      OrigParent = OrigParents.back();
-    else
-      OrigParent = OrigParents.front();
-
-    auto *OrigParentCatch =
-        dyn_cast<CatchPadInst>(OrigParent->getFirstNonPHI());
-    if (!OrigParentCatch || getEndPadForCatch(OrigParentCatch) != UnwindDest) {
-      DEBUG_WITH_TYPE(
-          "winehprepare-coloring",
-          dbgs() << "      removing unwind destination of original block \'"
-                 << OrigBlock << "\'.\n");
-      updateUnwindTerminator(OrigBlock);
-    }
-  } else if (auto *CleanupEnd = dyn_cast<CleanupEndPadInst>(EHPadInst)) {
-    // If the EH terminator unwinds to a cleanupendpad, that cleanupendpad
-    // must be ending a cleanuppad of either our clone parent or one
-    // one of the parents of the original funclet.
-    auto *CloneParentCP =
-        dyn_cast<CleanupPadInst>(CloneParent->getFirstNonPHI());
-    auto *EndedCP = CleanupEnd->getCleanupPad();
-    if (EndedCP == CloneParentCP) {
-      // If it is ending the cleanuppad of our cloned parent, then we
-      // want to remove the unwind destination of the EH terminator that
-      // we associated with the original funclet.
-      assert(isa<CatchEndPadInst>(OrigBlock->getFirstNonPHI()));
-      DEBUG_WITH_TYPE(
-          "winehprepare-coloring",
-          dbgs() << "      removing unwind destination of original block \'"
-                 << OrigBlock->getName() << "\'.\n");
-      updateUnwindTerminator(OrigBlock);
-    } else {
-      // If it isn't ending the cleanuppad of our clone parent, then we
-      // want to remove the unwind destination of the EH terminator that
-      // associated with our cloned funclet.
-      assert(isa<CatchEndPadInst>(CloneBlock->getFirstNonPHI()));
-      DEBUG_WITH_TYPE(
-          "winehprepare-coloring",
-          dbgs() << "      removing unwind destination of clone block \'"
-                 << CloneBlock->getName() << "\'.\n");
-      updateUnwindTerminator(CloneBlock);
-    }
-  } else {
-    // If the EH terminator unwinds to a catchpad, cleanuppad or
-    // terminatepad that EH pad must be a sibling of the funclet we're
-    // cloning.  We'll clone it later and update one of the catchendpad
-    // instrunctions that unwinds to it at that time.
-    assert(isa<CatchPadInst>(EHPadInst) || isa<CleanupPadInst>(EHPadInst) ||
-           isa<TerminatePadInst>(EHPadInst));
-  }
-}
-
-// If the terminator is a catchpad, we must also clone the catchendpad to which
-// it unwinds and add this to the clone parent's block list.  The catchendpad
-// unwinds to either its caller, a sibling EH pad, a cleanup end pad in its
-// parent funclet or a catch end pad in its grandparent funclet (which must be
-// coupled with the parent funclet).  If it has no unwind destination
-// (i.e. unwind to caller), there is nothing to be done. If the unwind
-// destination is a sibling EH pad, we will update the terminators later (in
-// resolveFuncletAncestryForPath).  If it unwinds to a cleanup end pad or a
-// catch end pad and this end pad corresponds to the clone parent, we will
-// remove the unwind destination in the original catchendpad. If it unwinds to
-// a cleanup end pad or a catch end pad that does not correspond to the clone
-// parent, we will remove the unwind destination in the cloned catchendpad.
-static void updateCatchTerminators(
-    Function &F, CatchPadInst *OrigCatch, CatchPadInst *CloneCatch,
-    std::vector<BasicBlock *> &OrigParents, BasicBlock *CloneParent,
-    ValueToValueMapTy &VMap,
-    std::map<BasicBlock *, std::set<BasicBlock *>> &BlockColors,
-    std::map<BasicBlock *, std::set<BasicBlock *>> &FuncletBlocks) {
-  // If we're cloning a catch pad that unwinds to a catchendpad, we also
-  // need to clone the catchendpad.  The coloring algorithm associates
-  // the catchendpad block with the funclet's parent, so we have some work
-  // to do here to figure out whether the original belongs to the clone
-  // parent or one of the original funclets other parents (it might have
-  // more than one at this point).  In either case, we might also need to
-  // remove the unwind edge if the catchendpad doesn't unwind to a block
-  // in the right grandparent funclet.
-  Instruction *I = CloneCatch->getUnwindDest()->getFirstNonPHI();
-  if (auto *CEP = dyn_cast<CatchEndPadInst>(I)) {
-    assert(BlockColors[CEP->getParent()].size() == 1);
-    BasicBlock *CEPFunclet = *(BlockColors[CEP->getParent()].begin());
-    BasicBlock *CEPCloneParent = nullptr;
-    CatchPadInst *PredCatch = nullptr;
-    if (CEPFunclet == CloneParent) {
-      // The catchendpad is in the clone parent, so we need to clone it
-      // and associate the clone with the original funclet's parent.  If
-      // the original funclet had multiple parents, we'll add it to the
-      // first parent that isn't the clone parent.  The logic in
-      // updateClonedEHPadUnwindToParent() will only remove the unwind edge
-      // if there is only one parent other than the clone parent, so we don't
-      // need to verify the ancestry.  The catchendpad will eventually be
-      // cloned into the correct parent and all invalid unwind edges will be
-      // removed.
-      for (auto *Parent : OrigParents) {
-        if (Parent != CloneParent) {
-          CEPCloneParent = Parent;
-          break;
-        }
-      }
-      PredCatch = OrigCatch;
-    } else {
-      CEPCloneParent = CloneParent;
-      PredCatch = CloneCatch;
-    }
-    assert(CEPCloneParent && PredCatch);
-    DEBUG_WITH_TYPE("winehprepare-coloring",
-                    dbgs() << "  Cloning catchendpad \'"
-                           << CEP->getParent()->getName() << "\' for funclet \'"
-                           << CEPCloneParent->getName() << "\'.\n");
-    BasicBlock *ClonedCEP = CloneBasicBlock(
-        CEP->getParent(), VMap, Twine(".from.", CEPCloneParent->getName()));
-    // Insert the clone immediately after the original to ensure determinism
-    // and to keep the same relative ordering of any funclet's blocks.
-    ClonedCEP->insertInto(&F, CEP->getParent()->getNextNode());
-    PredCatch->setUnwindDest(ClonedCEP);
-    FuncletBlocks[CEPCloneParent].insert(ClonedCEP);
-    BlockColors[ClonedCEP].insert(CEPCloneParent);
-    DEBUG_WITH_TYPE("winehprepare-coloring",
-                    dbgs() << "    Assigning color \'"
-                           << CEPCloneParent->getName() << "\' to block \'"
-                           << ClonedCEP->getName() << "\'.\n");
-    auto *ClonedCEPInst = cast<CatchEndPadInst>(ClonedCEP->getTerminator());
-    if (auto *Dest = ClonedCEPInst->getUnwindDest())
-      updateClonedEHPadUnwindToParent(Dest, OrigCatch->getUnwindDest(),
-                                      CloneCatch->getUnwindDest(), OrigParents,
-                                      CloneParent);
-  }
-}
-
-// While we are cloning a funclet because it has multiple parents, we will call
-// this routine to update the terminators for the original and cloned copies
-// of each basic block.  All blocks in the funclet have been clone by this time.
-// OrigBlock and CloneBlock will be identical except for their block label.
-//
-// If the terminator is a catchpad, we must also clone the catchendpad to which
-// it unwinds and in most cases update either the original catchendpad or the
-// clone.  See the updateCatchTerminators() helper routine for details.
-//
-// If the terminator is a catchret its successor is a block in its parent
-// funclet.  If the instruction returns to a block in the parent for which the
-// cloned funclet was created, the terminator in the original block must be
-// replaced by an unreachable instruction.  Otherwise the terminator in the
-// clone block must be replaced by an unreachable instruction.
-//
-// If the terminator is a cleanupret or cleanupendpad it either unwinds to
-// caller or unwinds to a sibling EH pad, a cleanup end pad in its parent
-// funclet or a catch end pad in its grandparent funclet (which must be
-// coupled with the parent funclet).  If it unwinds to caller there is
-// nothing to be done. If the unwind destination is a sibling EH pad, we will
-// update the terminators later (in resolveFuncletAncestryForPath).  If it
-// unwinds to a cleanup end pad or a catch end pad and this end pad corresponds
-// to the clone parent, we will replace the terminator in the original block
-// with an unreachable instruction. If it unwinds to a cleanup end pad or a
-// catch end pad that does not correspond to the clone parent, we will replace
-// the terminator in the clone block with an unreachable instruction.
-//
-// If the terminator is an invoke instruction, it unwinds either to a child
-// EH pad, a cleanup end pad in the current funclet, or a catch end pad in a
-// parent funclet (which ends either the current catch pad or a sibling
-// catch pad).  If it unwinds to a child EH pad, the child will have multiple
-// parents after this funclet is cloned and this case will be handled later in
-// the resolveFuncletAncestryForPath processing.  If it unwinds to a
-// cleanup end pad in the current funclet, the instruction remapping during
-// the cloning process should have already mapped the unwind destination to
-// the cloned copy of the cleanup end pad.  If it unwinds to a catch end pad
-// there are two possibilities: either the catch end pad is the unwind
-// destination for the catch pad we are currently cloning or it is the unwind
-// destination for a sibling catch pad.  If it it the unwind destination of the
-// catch pad we are cloning, we need to update the cloned invoke instruction
-// to unwind to the cloned catch end pad.  Otherwise, we will handle this
-// later (in resolveFuncletAncestryForPath).
-void WinEHPrepare::updateTerminatorsAfterFuncletClone(
-    Function &F, BasicBlock *OrigFunclet, BasicBlock *CloneFunclet,
-    BasicBlock *OrigBlock, BasicBlock *CloneBlock, BasicBlock *CloneParent,
-    ValueToValueMapTy &VMap, std::map<BasicBlock *, BasicBlock *> &Orig2Clone) {
-  // If the cloned block doesn't have an exceptional terminator, there is
-  // nothing to be done here.
-  TerminatorInst *CloneTerminator = CloneBlock->getTerminator();
-  if (!CloneTerminator->isExceptional())
-    return;
-
-  if (auto *CloneCatch = dyn_cast<CatchPadInst>(CloneTerminator)) {
-    // A cloned catch pad has a lot of wrinkles, so we'll call a helper function
-    // to update this case.
-    auto *OrigCatch = cast<CatchPadInst>(OrigBlock->getTerminator());
-    updateCatchTerminators(F, OrigCatch, CloneCatch,
-                           FuncletParents[OrigFunclet], CloneParent, VMap,
-                           BlockColors, FuncletBlocks);
-  } else if (auto *CRI = dyn_cast<CatchReturnInst>(CloneTerminator)) {
-    if (FuncletBlocks[CloneParent].count(CRI->getSuccessor())) {
-      BasicBlock *OrigParent;
-      // The original funclet may have more than two parents, but that's OK.
-      // We just need to remap the original catchret to any of the parents.
-      // All of the parents should have an entry in the EstrangedBlocks map
-      // if any of them do.
-      if (FuncletParents[OrigFunclet].front() == CloneParent)
-        OrigParent = FuncletParents[OrigFunclet].back();
-      else
-        OrigParent = FuncletParents[OrigFunclet].front();
-      for (succ_iterator SI = succ_begin(OrigBlock), SE = succ_end(OrigBlock);
-           SI != SE; ++SI)
-        (*SI)->removePredecessor(OrigBlock);
-      BasicBlock *LostBlock = EstrangedBlocks[OrigParent][CRI->getSuccessor()];
-      auto *OrigCatchRet = cast<CatchReturnInst>(OrigBlock->getTerminator());
-      if (LostBlock) {
-        OrigCatchRet->setSuccessor(LostBlock);
-      } else {
-        OrigCatchRet->eraseFromParent();
-        new UnreachableInst(OrigBlock->getContext(), OrigBlock);
-      }
-    } else {
-      for (succ_iterator SI = succ_begin(CloneBlock), SE = succ_end(CloneBlock);
-           SI != SE; ++SI)
-        (*SI)->removePredecessor(CloneBlock);
-      BasicBlock *LostBlock = EstrangedBlocks[CloneParent][CRI->getSuccessor()];
-      if (LostBlock) {
-        CRI->setSuccessor(LostBlock);
-      } else {
-        CRI->eraseFromParent();
-        new UnreachableInst(CloneBlock->getContext(), CloneBlock);
-      }
-    }
-  } else if (isa<CleanupReturnInst>(CloneTerminator) ||
-             isa<CleanupEndPadInst>(CloneTerminator)) {
-    BasicBlock *UnwindDest = nullptr;
-
-    // A cleanup pad can unwind through either a cleanupret or a cleanupendpad
-    // but both are handled the same way.
-    if (auto *CRI = dyn_cast<CleanupReturnInst>(CloneTerminator))
-      UnwindDest = CRI->getUnwindDest();
-    else if (auto *CEI = dyn_cast<CleanupEndPadInst>(CloneTerminator))
-      UnwindDest = CEI->getUnwindDest();
-
-    // If the instruction has no local unwind destination, there is nothing
-    // to be done.
-    if (!UnwindDest)
-      return;
-
-    // The unwind destination may be a sibling EH pad, a catchendpad in
-    // a grandparent funclet (ending a catchpad in the parent) or a cleanup
-    // cleanupendpad in the parent.  Call a helper routine to diagnose this
-    // and remove either the clone or original terminator as needed.
-    updateClonedEHPadUnwindToParent(UnwindDest, OrigBlock, CloneBlock,
-                                    FuncletParents[OrigFunclet], CloneParent);
-  } else if (auto *II = dyn_cast<InvokeInst>(CloneTerminator)) {
-    BasicBlock *UnwindDest = II->getUnwindDest();
-    assert(UnwindDest && "Invoke unwinds to a null destination.");
-    assert(UnwindDest->isEHPad() && "Invoke does not unwind to an EH pad.");
-    auto *EHPadInst = UnwindDest->getFirstNonPHI();
-    if (isa<CleanupEndPadInst>(EHPadInst)) {
-      // An invoke that unwinds to a cleanup end pad must be in a cleanup pad.
-      assert(isa<CleanupPadInst>(CloneFunclet->getFirstNonPHI()) &&
-             "Unwinding to cleanup end pad from a non cleanup pad funclet.");
-      // The funclet cloning should have remapped the destination to the cloned
-      // cleanup end pad.
-      assert(FuncletBlocks[CloneFunclet].count(UnwindDest) &&
-             "Unwind destination for invoke was not updated during cloning.");
-    } else if (isa<CatchEndPadInst>(EHPadInst)) {
-      auto *OrigCatch = cast<CatchPadInst>(OrigFunclet->getFirstNonPHI());
-      auto *CloneCatch = cast<CatchPadInst>(CloneFunclet->getFirstNonPHI());
-      if (OrigCatch->getUnwindDest() == UnwindDest) {
-        // If the invoke unwinds to a catch end pad that is the unwind
-        // destination for the original catch pad, the cloned invoke should
-        // unwind to the cloned catch end pad.
-        II->setUnwindDest(CloneCatch->getUnwindDest());
-      } else if (CloneCatch->getUnwindDest() == UnwindDest) {
-        // If the invoke unwinds to a catch end pad that is the unwind
-        // destination for the clone catch pad, the original invoke should
-        // unwind to the unwind destination of the original catch pad.
-        // This happens when the catch end pad is matched to the clone
-        // parent when the catchpad instruction is cloned and the original
-        // invoke instruction unwinds to the original catch end pad (which
-        // is now the unwind destination of the cloned catch pad).
-        auto *OrigInvoke = cast<InvokeInst>(OrigBlock->getTerminator());
-        OrigInvoke->setUnwindDest(OrigCatch->getUnwindDest());
-      } else {
-        // If the invoke unwinds to a catch end pad that is not the unwind
-        // destination for the original catch pad, it must be the unwind
-        // destination for a sibling catch end pad.  We'll handle that case
-        // later.
-        assert((getEndPadForCatch(OrigCatch) == UnwindDest ||
-                getEndPadForCatch(CloneCatch) == UnwindDest) &&
-               "Invoke within catch pad unwinds to an invalid catch end pad.");
-      }
-    }
-  }
-}
-
-// Clones all blocks used by the specified funclet to avoid the funclet having
-// multiple parent funclets.  All terminators in the parent that unwind to the
-// original funclet are remapped to unwind to the clone.  Any terminator in the
-// original funclet which returned to this parent is converted to an unreachable
-// instruction. Likewise, any terminator in the cloned funclet which returns to
-// a parent funclet other than the specified parent is converted to an
-// unreachable instruction.
-BasicBlock *WinEHPrepare::cloneFuncletForParent(Function &F,
-                                                BasicBlock *FuncletEntry,
-                                                BasicBlock *Parent) {
-  std::set<BasicBlock *> &BlocksInFunclet = FuncletBlocks[FuncletEntry];
-
-  DEBUG_WITH_TYPE("winehprepare-coloring",
-                  dbgs() << "Cloning funclet \'" << FuncletEntry->getName()
-                         << "\' for parent \'" << Parent->getName() << "\'.\n");
-
-  std::map<BasicBlock *, BasicBlock *> Orig2Clone;
-  ValueToValueMapTy VMap;
-  for (BasicBlock *BB : BlocksInFunclet) {
-    // Create a new basic block and copy instructions into it.
-    BasicBlock *CBB =
-        CloneBasicBlock(BB, VMap, Twine(".from.", Parent->getName()));
-
-    // Insert the clone immediately after the original to ensure determinism
-    // and to keep the same relative ordering of any funclet's blocks.
-    CBB->insertInto(&F, BB->getNextNode());
-
-    // Add basic block mapping.
-    VMap[BB] = CBB;
-
-    // Record delta operations that we need to perform to our color mappings.
-    Orig2Clone[BB] = CBB;
-  } // end for (BasicBlock *BB : BlocksInFunclet)
-
-  BasicBlock *ClonedFunclet = Orig2Clone[FuncletEntry];
-  assert(ClonedFunclet);
-
-  // Set the coloring for the blocks we just cloned.
-  std::set<BasicBlock *> &ClonedBlocks = FuncletBlocks[ClonedFunclet];
-  for (auto &BBMapping : Orig2Clone) {
-    BasicBlock *NewBlock = BBMapping.second;
-    ClonedBlocks.insert(NewBlock);
-    BlockColors[NewBlock].insert(ClonedFunclet);
-
-    DEBUG_WITH_TYPE("winehprepare-coloring",
-                    dbgs() << "  Assigning color \'" << ClonedFunclet->getName()
-                           << "\' to block \'" << NewBlock->getName()
-                           << "\'.\n");
-
-    // Use the VMap to remap the instructions in this cloned block.
-    for (Instruction &I : *NewBlock)
-      RemapInstruction(&I, VMap, RF_IgnoreMissingEntries);
-  }
-
-  // All the cloned blocks have to be colored in the loop above before we can
-  // update the terminators because doing so can require checking the color of
-  // other blocks in the cloned funclet.
-  for (auto &BBMapping : Orig2Clone) {
-    BasicBlock *OldBlock = BBMapping.first;
-    BasicBlock *NewBlock = BBMapping.second;
-
-    // Update the terminator, if necessary, in both the original block and the
-    // cloned so that the original funclet never returns to a block in the
-    // clone parent and the clone funclet never returns to a block in any other
-    // of the original funclet's parents.
-    updateTerminatorsAfterFuncletClone(F, FuncletEntry, ClonedFunclet, OldBlock,
-                                       NewBlock, Parent, VMap, Orig2Clone);
-
-    // Check to see if the cloned block successor has PHI nodes. If so, we need
-    // to add entries to the PHI nodes for the cloned block now.
-    for (BasicBlock *SuccBB : successors(NewBlock)) {
-      for (Instruction &SuccI : *SuccBB) {
-        auto *SuccPN = dyn_cast<PHINode>(&SuccI);
-        if (!SuccPN)
-          break;
-
-        // Ok, we have a PHI node.  Figure out what the incoming value was for
-        // the OldBlock.
-        int OldBlockIdx = SuccPN->getBasicBlockIndex(OldBlock);
-        if (OldBlockIdx == -1)
-          break;
-        Value *IV = SuccPN->getIncomingValue(OldBlockIdx);
-
-        // Remap the value if necessary.
-        if (auto *Inst = dyn_cast<Instruction>(IV)) {
-          ValueToValueMapTy::iterator I = VMap.find(Inst);
-          if (I != VMap.end())
-            IV = I->second;
-        }
-
-        SuccPN->addIncoming(IV, NewBlock);
-      }
-    }
-  }
-
-  // Erase the clone's parent from the original funclet's parent list.
-  std::vector<BasicBlock *> &Parents = FuncletParents[FuncletEntry];
-  Parents.erase(std::remove(Parents.begin(), Parents.end(), Parent),
-                Parents.end());
-
-  // Store the cloned funclet's parent.
-  assert(std::find(FuncletParents[ClonedFunclet].begin(),
-                   FuncletParents[ClonedFunclet].end(),
-                   Parent) == std::end(FuncletParents[ClonedFunclet]));
-  FuncletParents[ClonedFunclet].push_back(Parent);
-
-  // Copy any children of the original funclet to the clone.  We'll either
-  // clone them too or make that path unreachable when we take the next step
-  // in resolveFuncletAncestryForPath().
-  for (auto *Child : FuncletChildren[FuncletEntry]) {
-    assert(std::find(FuncletChildren[ClonedFunclet].begin(),
-                     FuncletChildren[ClonedFunclet].end(),
-                     Child) == std::end(FuncletChildren[ClonedFunclet]));
-    FuncletChildren[ClonedFunclet].push_back(Child);
-    assert(std::find(FuncletParents[Child].begin(), FuncletParents[Child].end(),
-                     ClonedFunclet) == std::end(FuncletParents[Child]));
-    FuncletParents[Child].push_back(ClonedFunclet);
-  }
-
-  // Find any blocks that unwound to the original funclet entry from the
-  // clone parent block and remap them to the clone.
-  for (auto *U : FuncletEntry->users()) {
-    auto *UT = dyn_cast<TerminatorInst>(U);
-    if (!UT)
-      continue;
-    BasicBlock *UBB = UT->getParent();
-    assert(BlockColors[UBB].size() == 1);
-    BasicBlock *UFunclet = *(BlockColors[UBB].begin());
-    // Funclets shouldn't be able to loop back on themselves.
-    assert(UFunclet != FuncletEntry);
-    // If this instruction unwinds to the original funclet from the clone
-    // parent, remap the terminator so that it unwinds to the clone instead.
-    // We will perform a similar transformation for siblings after all
-    // the siblings have been cloned.
-    if (UFunclet == Parent) {
-      // We're about to break the path from this block to the uncloned funclet
-      // entry, so remove it as a predeccessor to clean up the PHIs.
-      FuncletEntry->removePredecessor(UBB);
-      TerminatorInst *Terminator = UBB->getTerminator();
-      RemapInstruction(Terminator, VMap, RF_IgnoreMissingEntries);
-    }
-  }
-
-  // This asserts a condition that is relied upon inside the loop below,
-  // namely that no predecessors of the original funclet entry block
-  // are also predecessors of the cloned funclet entry block.
-  assert(std::all_of(pred_begin(FuncletEntry), pred_end(FuncletEntry),
-                     [&ClonedFunclet](BasicBlock *Pred) {
-                       return std::find(pred_begin(ClonedFunclet),
-                                        pred_end(ClonedFunclet),
-                                        Pred) == pred_end(ClonedFunclet);
-                     }));
-
-  // Remove any invalid PHI node entries in the cloned funclet.cl
-  std::vector<PHINode *> PHIsToErase;
-  for (Instruction &I : *ClonedFunclet) {
-    auto *PN = dyn_cast<PHINode>(&I);
-    if (!PN)
-      break;
-
-    // Predecessors of the original funclet do not reach the cloned funclet,
-    // but the cloning process assumes they will.  Remove them now.
-    for (auto *Pred : predecessors(FuncletEntry))
-      PN->removeIncomingValue(Pred, false);
-  }
-  for (auto *PN : PHIsToErase)
-    PN->eraseFromParent();
-
-  // Replace the original funclet in the parent's children vector with the
-  // cloned funclet.
-  for (auto &It : FuncletChildren[Parent]) {
-    if (It == FuncletEntry) {
-      It = ClonedFunclet;
-      break;
-    }
-  }
-
-  return ClonedFunclet;
-}
-
-// Removes the unwind edge for any exceptional terminators within the specified
-// parent funclet that previously unwound to the specified child funclet.
-void WinEHPrepare::makeFuncletEdgeUnreachable(BasicBlock *Parent,
-                                              BasicBlock *Child) {
-  for (BasicBlock *BB : FuncletBlocks[Parent]) {
-    TerminatorInst *Terminator = BB->getTerminator();
-    if (!Terminator->isExceptional())
-      continue;
-
-    // Look for terninators that unwind to the child funclet.
-    BasicBlock *UnwindDest = nullptr;
-    if (auto *I = dyn_cast<InvokeInst>(Terminator))
-      UnwindDest = I->getUnwindDest();
-    else if (auto *I = dyn_cast<CatchEndPadInst>(Terminator))
-      UnwindDest = I->getUnwindDest();
-    else if (auto *I = dyn_cast<TerminatePadInst>(Terminator))
-      UnwindDest = I->getUnwindDest();
-    // cleanupendpad, catchret and cleanupret don't represent a parent-to-child
-    // funclet transition, so we don't need to consider them here.
-
-    // If the child funclet is the unwind destination, replace the terminator
-    // with an unreachable instruction.
-    if (UnwindDest == Child)
-      removeUnwindEdge(BB);
-  }
-  // The specified parent is no longer a parent of the specified child.
-  std::vector<BasicBlock *> &Children = FuncletChildren[Parent];
-  Children.erase(std::remove(Children.begin(), Children.end(), Child),
-                 Children.end());
-}
-
-// This routine is called after funclets with multiple parents are cloned for
-// a specific parent.  Here we look for children of the specified funclet that
-// unwind to other children of that funclet and update the unwind destinations
-// to ensure that each sibling is connected to the correct clone of the sibling
-// to which it unwinds.
-static void updateSiblingToSiblingUnwind(
-    BasicBlock *CurFunclet,
-    std::map<BasicBlock *, std::set<BasicBlock *>> &BlockColors,
-    std::map<BasicBlock *, std::set<BasicBlock *>> &FuncletBlocks,
-    std::map<BasicBlock *, std::vector<BasicBlock *>> &FuncletParents,
-    std::map<BasicBlock *, std::vector<BasicBlock *>> &FuncletChildren,
-    std::map<BasicBlock *, BasicBlock *> &Funclet2Orig) {
-  // Remap any bad sibling-to-sibling transitions for funclets that
-  // we just cloned.
-  for (BasicBlock *ChildFunclet : FuncletChildren[CurFunclet]) {
-    bool NeedOrigInvokeRemapping = false;
-    for (auto *BB : FuncletBlocks[ChildFunclet]) {
-      TerminatorInst *Terminator = BB->getTerminator();
-      if (!Terminator->isExceptional())
-        continue;
-
-      // See if this terminator has an unwind destination.
-      // Note that catchendpads are handled when the associated catchpad
-      // is cloned.  They don't fit the pattern we're looking for here.
-      BasicBlock *UnwindDest = nullptr;
-      if (auto *II = dyn_cast<InvokeInst>(Terminator)) {
-        UnwindDest = II->getUnwindDest();
-        assert(UnwindDest && "Invoke unwinds to a null destination.");
-        assert(UnwindDest->isEHPad() && "Invoke does not unwind to an EH pad.");
-        auto *EHPadInst = UnwindDest->getFirstNonPHI();
-        if (isa<CatchEndPadInst>(EHPadInst)) {
-          // If the invoke unwind destination is the unwind destination for
-          // the current child catch pad funclet, there is nothing to be done.
-          auto *CurCatch = cast<CatchPadInst>(ChildFunclet->getFirstNonPHI());
-          if (CurCatch->getUnwindDest() == UnwindDest)
-            continue;
-
-          // Otherwise, the invoke unwinds to a catch end pad that is the unwind
-          // destination another catch pad in the unwind chain from either the
-          // current catch pad or one of its clones.  If it is already the
-          // catch end pad at the end unwind chain from the current catch pad,
-          // we'll need to check the invoke instructions in the original funclet
-          // later.  Otherwise, we need to remap this invoke now.
-          BasicBlock *CurCatchEnd = getEndPadForCatch(CurCatch);
-          if (CurCatchEnd == UnwindDest)
-            NeedOrigInvokeRemapping = true;
-          else
-            II->setUnwindDest(CurCatchEnd);
-          continue;
-        }
-        // All other unwind scenarios for the invoke are handled elsewhere.
-        continue;
-      } else if (auto *I = dyn_cast<CatchPadInst>(Terminator)) {
-        UnwindDest = I->getUnwindDest();
-        // The catchendpad is not a sibling destination.  This case should
-        // have been handled in cloneFuncletForParent().
-        if (isa<CatchEndPadInst>(Terminator)) {
-          assert(BlockColors[UnwindDest].size() == 1 &&
-                 "Cloned catchpad unwinds to an pad with multiple parents.");
-          assert(FuncletParents[UnwindDest].front() == CurFunclet &&
-                 "Cloned catchpad unwinds to the wrong parent.");
-          continue;
-        }
-      } else {
-        if (auto *I = dyn_cast<CleanupReturnInst>(Terminator))
-          UnwindDest = I->getUnwindDest();
-        else if (auto *I = dyn_cast<CleanupEndPadInst>(Terminator))
-          UnwindDest = I->getUnwindDest();
-
-        // If the cleanup unwinds to caller, there is nothing to be done.
-        if (!UnwindDest)
-          continue;
-      }
-
-      // If the destination is not a cleanup pad, catch pad or terminate pad
-      // we don't need to handle it here.
-      Instruction *EHPad = UnwindDest->getFirstNonPHI();
-      if (!isa<CleanupPadInst>(EHPad) && !isa<CatchPadInst>(EHPad) &&
-          !isa<TerminatePadInst>(EHPad))
-        continue;
-
-      // If it is one of these, then it is either a sibling of the current
-      // child funclet or a clone of one of those siblings.
-      // If it is a sibling, no action is needed.
-      if (FuncletParents[UnwindDest].size() == 1 &&
-          FuncletParents[UnwindDest].front() == CurFunclet)
-        continue;
-
-      // If the unwind destination is a clone of a sibling, we need to figure
-      // out which sibling it is a clone of and use that sibling as the
-      // unwind destination.
-      BasicBlock *DestOrig = Funclet2Orig[UnwindDest];
-      BasicBlock *TargetSibling = nullptr;
-      for (auto &Mapping : Funclet2Orig) {
-        if (Mapping.second != DestOrig)
-          continue;
-        BasicBlock *MappedFunclet = Mapping.first;
-        if (FuncletParents[MappedFunclet].size() == 1 &&
-            FuncletParents[MappedFunclet].front() == CurFunclet) {
-          TargetSibling = MappedFunclet;
-        }
-      }
-      // If we didn't find the sibling we were looking for then the
-      // unwind destination is not a clone of one of child's siblings.
-      // That's unexpected.
-      assert(TargetSibling && "Funclet unwinds to unexpected destination.");
-
-      // Update the terminator instruction to unwind to the correct sibling.
-      if (auto *I = dyn_cast<CatchPadInst>(Terminator))
-        I->setUnwindDest(TargetSibling);
-      else if (auto *I = dyn_cast<CleanupReturnInst>(Terminator))
-        I->setUnwindDest(TargetSibling);
-      else if (auto *I = dyn_cast<CleanupEndPadInst>(Terminator))
-        I->setUnwindDest(TargetSibling);
-    }
-    if (NeedOrigInvokeRemapping) {
-      // To properly remap invoke instructions that unwind to catch end pads
-      // that are not the unwind destination of the catch pad funclet in which
-      // the invoke appears, we must also look at the uncloned invoke in the
-      // original funclet.  If we saw an invoke that was already properly
-      // unwinding to a sibling's catch end pad, we need to check the invokes
-      // in the original funclet.
-      BasicBlock *OrigFunclet = Funclet2Orig[ChildFunclet];
-      for (auto *BB : FuncletBlocks[OrigFunclet]) {
-        auto *II = dyn_cast<InvokeInst>(BB->getTerminator());
-        if (!II)
-          continue;
-
-        BasicBlock *UnwindDest = II->getUnwindDest();
-        assert(UnwindDest && "Invoke unwinds to a null destination.");
-        assert(UnwindDest->isEHPad() && "Invoke does not unwind to an EH pad.");
-        auto *CEP = dyn_cast<CatchEndPadInst>(UnwindDest->getFirstNonPHI());
-        if (!CEP)
-          continue;
-        // If the invoke unwind destination is the unwind destination for
-        // the original catch pad funclet, there is nothing to be done.
-        auto *OrigCatch = cast<CatchPadInst>(OrigFunclet->getFirstNonPHI());
-        if (OrigCatch->getUnwindDest() == UnwindDest)
-          continue;
-
-        // Otherwise, the invoke unwinds to a catch end pad that is the unwind
-        // destination another catch pad in the unwind chain from either the
-        // current catch pad or one of its clones.  If it is not already the
-        // catch end pad at the end unwind chain from the current catch pad,
-        // we need to remap this invoke now.
-        BasicBlock *OrigCatchEnd = getEndPadForCatch(OrigCatch);
-        if (OrigCatchEnd != UnwindDest)
-          II->setUnwindDest(OrigCatchEnd);
-      }
-    }
-  }
-}
-
-void WinEHPrepare::resolveFuncletAncestry(
-    Function &F, SmallVectorImpl<BasicBlock *> &EntryBlocks) {
-  // Most of the time this will be unnecessary.  If the conditions arise that
-  // require this work, this flag will be set.
-  if (!FuncletCloningRequired)
-    return;
-
-  // Funclet2Orig is used to map any cloned funclets back to the original
-  // funclet from which they were cloned.  The map is seeded with the
-  // original funclets mapping to themselves.
-  std::map<BasicBlock *, BasicBlock *> Funclet2Orig;
-  for (auto *Funclet : EntryBlocks)
-    Funclet2Orig[Funclet] = Funclet;
-
-  // Start with the entry funclet and walk the funclet parent-child tree.
-  SmallVector<BasicBlock *, 4> FuncletPath;
-  FuncletPath.push_back(&(F.getEntryBlock()));
-  resolveFuncletAncestryForPath(F, FuncletPath, Funclet2Orig);
-}
-
-// Walks the funclet control flow, cloning any funclets that have more than one
-// parent funclet and breaking any cyclic unwind chains so that the path becomes
-// unreachable at the point where a funclet would have unwound to a funclet that
-// was already in the chain.
-void WinEHPrepare::resolveFuncletAncestryForPath(
-    Function &F, SmallVectorImpl<BasicBlock *> &FuncletPath,
-    std::map<BasicBlock *, BasicBlock *> &Funclet2Orig) {
-  bool ClonedAnyChildren = false;
-  BasicBlock *CurFunclet = FuncletPath.back();
-  // Copy the children vector because we might changing it.
-  std::vector<BasicBlock *> Children(FuncletChildren[CurFunclet]);
-  for (BasicBlock *ChildFunclet : Children) {
-    // Don't allow the funclet chain to unwind back on itself.
-    // If this funclet is already in the current funclet chain, make the
-    // path to it through the current funclet unreachable.
-    bool IsCyclic = false;
-    BasicBlock *ChildIdentity = Funclet2Orig[ChildFunclet];
-    for (BasicBlock *Ancestor : FuncletPath) {
-      BasicBlock *AncestorIdentity = Funclet2Orig[Ancestor];
-      if (AncestorIdentity == ChildIdentity) {
-        IsCyclic = true;
-        break;
-      }
-    }
-    // If the unwind chain wraps back on itself, break the chain.
-    if (IsCyclic) {
-      makeFuncletEdgeUnreachable(CurFunclet, ChildFunclet);
-      continue;
-    }
-    // If this child funclet has other parents, clone the entire funclet.
-    if (FuncletParents[ChildFunclet].size() > 1) {
-      ChildFunclet = cloneFuncletForParent(F, ChildFunclet, CurFunclet);
-      Funclet2Orig[ChildFunclet] = ChildIdentity;
-      ClonedAnyChildren = true;
-    }
-    FuncletPath.push_back(ChildFunclet);
-    resolveFuncletAncestryForPath(F, FuncletPath, Funclet2Orig);
-    FuncletPath.pop_back();
-  }
-  // If we didn't clone any children, we can return now.
-  if (!ClonedAnyChildren)
-    return;
-
-  updateSiblingToSiblingUnwind(CurFunclet, BlockColors, FuncletBlocks,
-                               FuncletParents, FuncletChildren, Funclet2Orig);
-}
-
-void WinEHPrepare::colorFunclets(Function &F,
-                                 SmallVectorImpl<BasicBlock *> &EntryBlocks) {
-  ::colorFunclets(F, EntryBlocks, BlockColors, FuncletBlocks);
 
   // The processing above actually accumulated the parent set for this
   // funclet into the color set for its entry; use the parent set to
@@ -1496,27 +657,18 @@ void WinEHPrepare::colorFunclets(Function &F,
   // that transitions to the child funclet).
   for (BasicBlock *FuncletEntry : EntryBlocks) {
     std::set<BasicBlock *> &ColorMapItem = BlockColors[FuncletEntry];
-    // It will be rare for funclets to have multiple parents, but if any
-    // do we need to clone the funclet later to address that.  Here we
-    // set a flag indicating that this case has arisen so that we don't
-    // have to do a lot of checking later to handle the more common case.
-    if (ColorMapItem.size() > 1)
-      FuncletCloningRequired = true;
-    for (BasicBlock *Parent : ColorMapItem) {
-      assert(std::find(FuncletChildren[Parent].begin(),
-                       FuncletChildren[Parent].end(),
-                       FuncletEntry) == std::end(FuncletChildren[Parent]));
-      FuncletChildren[Parent].push_back(FuncletEntry);
-      assert(std::find(FuncletParents[FuncletEntry].begin(),
-                       FuncletParents[FuncletEntry].end(),
-                       Parent) == std::end(FuncletParents[FuncletEntry]));
-      FuncletParents[FuncletEntry].push_back(Parent);
-    }
+    for (BasicBlock *Parent : ColorMapItem)
+      FuncletChildren[Parent].insert(FuncletEntry);
     ColorMapItem.clear();
     ColorMapItem.insert(FuncletEntry);
   }
 }
 
+void WinEHPrepare::colorFunclets(Function &F,
+                                 SmallVectorImpl<BasicBlock *> &EntryBlocks) {
+  ::colorFunclets(F, EntryBlocks, BlockColors, FuncletBlocks, FuncletChildren);
+}
+
 void llvm::calculateCatchReturnSuccessorColors(const Function *Fn,
                                                WinEHFuncInfo &FuncInfo) {
   SmallVector<BasicBlock *, 4> EntryBlocks;
@@ -1526,18 +678,10 @@ void llvm::calculateCatchReturnSuccessorColors(const Function *Fn,
 
   std::map<BasicBlock *, std::set<BasicBlock *>> BlockColors;
   std::map<BasicBlock *, std::set<BasicBlock *>> FuncletBlocks;
+  std::map<BasicBlock *, std::set<BasicBlock *>> FuncletChildren;
   // Figure out which basic blocks belong to which funclets.
   colorFunclets(const_cast<Function &>(*Fn), EntryBlocks, BlockColors,
-                FuncletBlocks);
-
-  // The static colorFunclets routine assigns multiple colors to funclet entries
-  // because that information is needed to calculate funclets' parent-child
-  // relationship, but we don't need those relationship here and ultimately the
-  // entry blocks should have the color of the funclet they begin.
-  for (BasicBlock *FuncletEntry : EntryBlocks) {
-    BlockColors[FuncletEntry].clear();
-    BlockColors[FuncletEntry].insert(FuncletEntry);
-  }
+                FuncletBlocks, FuncletChildren);
 
   // We need to find the catchret successors.  To do this, we must first find
   // all the catchpad funclets.
@@ -1628,71 +772,13 @@ void WinEHPrepare::cloneCommonBlocks(
 
     std::map<BasicBlock *, BasicBlock *> Orig2Clone;
     ValueToValueMapTy VMap;
-    for (auto BlockIt = BlocksInFunclet.begin(),
-              BlockEnd = BlocksInFunclet.end();
-         BlockIt != BlockEnd;) {
-      // Increment the iterator inside the loop because we might be removing
-      // blocks from the set.
-      BasicBlock *BB = *BlockIt++;
+    for (BasicBlock *BB : BlocksInFunclet) {
       std::set<BasicBlock *> &ColorsForBB = BlockColors[BB];
       // We don't need to do anything if the block is monochromatic.
       size_t NumColorsForBB = ColorsForBB.size();
       if (NumColorsForBB == 1)
         continue;
 
-      // If this block is a catchendpad, it shouldn't be cloned.
-      // We will only see a catchendpad with multiple colors in the case where
-      // some funclet has multiple parents.  In that case, the color will be
-      // resolved during the resolveFuncletAncestry processing.
-      // For now, find the catchpad that unwinds to this block and assign
-      // that catchpad's first parent to be the color for this block.
-      if (isa<CatchEndPadInst>(BB->getFirstNonPHI())) {
-        assert(
-            FuncletCloningRequired &&
-            "Found multi-colored catchendpad with no multi-parent funclets.");
-        BasicBlock *CatchParent = nullptr;
-        // There can only be one catchpad predecessor for a catchendpad.
-        for (BasicBlock *PredBB : predecessors(BB)) {
-          if (isa<CatchPadInst>(PredBB->getTerminator())) {
-            CatchParent = PredBB;
-            break;
-          }
-        }
-        // There must be one catchpad predecessor for a catchendpad.
-        assert(CatchParent && "No catchpad found for catchendpad.");
-
-        // If the catchpad has multiple parents, we'll clone the catchendpad
-        // when we clone the catchpad funclet and insert it into the correct
-        // funclet.  For now, we just select the first parent of the catchpad
-        // and give the catchendpad that color.
-        BasicBlock *CorrectColor = FuncletParents[CatchParent].front();
-        assert(FuncletBlocks[CorrectColor].count(BB));
-        assert(BlockColors[BB].count(CorrectColor));
-
-        // Remove this block from the FuncletBlocks set of any funclet that
-        // isn't the funclet whose color we just selected.
-        for (auto It = BlockColors[BB].begin(), End = BlockColors[BB].end();
-             It != End; ) {
-          // The iterator must be incremented here because we are removing
-          // elements from the set we're walking.
-          auto Temp = It++;
-          BasicBlock *ContainingFunclet = *Temp;
-          if (ContainingFunclet != CorrectColor) {
-            FuncletBlocks[ContainingFunclet].erase(BB);
-            BlockColors[BB].erase(Temp);
-          }
-        }
-
-        // This should leave just one color for BB.
-        assert(BlockColors[BB].size() == 1);
-        continue;
-      }
-
-      DEBUG_WITH_TYPE("winehprepare-coloring",
-                      dbgs() << "  Cloning block \'" << BB->getName()
-                              << "\' for funclet \'" << FuncletPadBB->getName()
-                              << "\'.\n");
-
       // Create a new basic block and copy instructions into it!
       BasicBlock *CBB =
           CloneBasicBlock(BB, VMap, Twine(".for.", FuncletPadBB->getName()));
@@ -1720,52 +806,8 @@ void WinEHPrepare::cloneCommonBlocks(
       BlocksInFunclet.insert(NewBlock);
       BlockColors[NewBlock].insert(FuncletPadBB);
 
-      DEBUG_WITH_TYPE("winehprepare-coloring",
-                      dbgs() << "  Assigned color \'" << FuncletPadBB->getName()
-                              << "\' to block \'" << NewBlock->getName()
-                              << "\'.\n");
-
       BlocksInFunclet.erase(OldBlock);
       BlockColors[OldBlock].erase(FuncletPadBB);
-
-      DEBUG_WITH_TYPE("winehprepare-coloring",
-                      dbgs() << "  Removed color \'" << FuncletPadBB->getName()
-                              << "\' from block \'" << OldBlock->getName()
-                              << "\'.\n");
-
-      // If we are cloning a funclet that might share a child funclet with
-      // another funclet, look to see if the cloned block is reached from a
-      // catchret instruction.  If so, save this association so we can retrieve
-      // the possibly orphaned clone when we clone the child funclet.
-      if (FuncletCloningRequired) {
-        for (auto *Pred : predecessors(OldBlock)) {
-          auto *Terminator = Pred->getTerminator();
-          if (!isa<CatchReturnInst>(Terminator))
-            continue;
-          // If this block is reached from a catchret instruction in a funclet
-          // that has multiple parents, it will have a color for each of those
-          // parents.  We just removed the color of one of the parents, but
-          // the cloned block will be unreachable until we clone the child
-          // funclet that contains the catchret instruction.  In that case we
-          // need to create a mapping that will let us find the cloned block
-          // later and associate it with the cloned child funclet.
-          bool BlockWillBeEstranged = false;
-          for (auto *Color : BlockColors[Pred]) {
-            if (FuncletParents[Color].size() > 1) {
-              BlockWillBeEstranged = true;
-              break; // Breaks out of the color loop
-            }
-          }
-          if (BlockWillBeEstranged) {
-            EstrangedBlocks[FuncletPadBB][OldBlock] = NewBlock;
-            DEBUG_WITH_TYPE("winehprepare-coloring",
-                            dbgs() << "  Saved mapping of estranged block \'"
-                                  << NewBlock->getName() << "\' for \'"
-                                  << FuncletPadBB->getName() << "\'.\n");
-            break; // Breaks out of the predecessor loop
-          }
-        }
-      }
     }
 
     // Loop over all of the instructions in this funclet, fixing up operand
@@ -1952,8 +994,6 @@ bool WinEHPrepare::prepareExplicitEH(
 
   cloneCommonBlocks(F, EntryBlocks);
 
-  resolveFuncletAncestry(F, EntryBlocks);
-
   if (!DisableCleanups) {
     removeImplausibleTerminators(F);
 
@@ -1965,9 +1005,6 @@ bool WinEHPrepare::prepareExplicitEH(
   BlockColors.clear();
   FuncletBlocks.clear();
   FuncletChildren.clear();
-  FuncletParents.clear();
-  EstrangedBlocks.clear();
-  FuncletCloningRequired = false;
 
   return true;
 }