ADT: Remove last implicit ilist iterator conversions, NFC

Some implicit ilist iterator conversions have crept back into Analysis,
Transforms, Hexagon, and llvm-stress.  This removes them.

I'll commit a patch immediately after this to disallow them (in a
separate patch so that it's easy to revert if necessary).

llvm-svn: 252371
diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
index 25b83e2..e0c598f 100644
--- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -2400,7 +2400,7 @@
   if (PHI)
     return PHI;
 
-  PHI = PHINode::Create(V->getType(), 2, "simplifycfg.merge", Succ->begin());
+  PHI = PHINode::Create(V->getType(), 2, "simplifycfg.merge", &Succ->front());
   PHI->addIncoming(V, BB);
   for (BasicBlock *PredBB : predecessors(Succ))
     if (PredBB != BB)
@@ -2500,8 +2500,8 @@
   Value *QPHI = ensureValueAvailableInSuccessor(QStore->getValueOperand(),
                                                 QStore->getParent(), PPHI);
 
-  IRBuilder<> QB(PostBB->getFirstInsertionPt());
-  
+  IRBuilder<> QB(&*PostBB->getFirstInsertionPt());
+
   Value *PPred = PStore->getParent() == PTB ? PCond : QB.CreateNot(PCond);
   Value *QPred = QStore->getParent() == QTB ? QCond : QB.CreateNot(QCond);
 
@@ -2511,7 +2511,8 @@
     QPred = QB.CreateNot(QPred);
   Value *CombinedPred = QB.CreateOr(PPred, QPred);
 
-  auto *T = SplitBlockAndInsertIfThen(CombinedPred, QB.GetInsertPoint(), false);
+  auto *T =
+      SplitBlockAndInsertIfThen(CombinedPred, &*QB.GetInsertPoint(), false);
   QB.SetInsertPoint(T);
   StoreInst *SI = cast<StoreInst>(QB.CreateStore(QPHI, Address));
   AAMDNodes AAMD;