[NFC][RemoveDIs] Always use iterators for inserting PHIs

It's becoming potentially unsafe to insert a PHI instruction using a plain
Instruction pointer. Switch all the remaining sites that create and insert
PHIs to use iterators instead. For example, the code in
ComplexDeinterleavingPass.cpp is definitely at-risk of mixing PHIs and
debug-info.

Author: jmorse

llvm/lib/CodeGen/CodeGenPrepare.cpp

@@ -4130,7 +4130,7 @@ class AddressingModeCombiner {
         PHINode *CurrentPhi = cast<PHINode>(Current);
         unsigned PredCount = CurrentPhi->getNumIncomingValues();
         PHINode *PHI =
-            PHINode::Create(CommonType, PredCount, "sunk_phi", CurrentPhi);
+            PHINode::Create(CommonType, PredCount, "sunk_phi", CurrentPhi->getIterator());
         Map[Current] = PHI;
         ST.insertNewPhi(PHI);
         append_range(Worklist, CurrentPhi->incoming_values());
@@ -6436,7 +6436,7 @@ bool CodeGenPrepare::optimizePhiType(
   }
   for (PHINode *Phi : PhiNodes)
     ValMap[Phi] = PHINode::Create(ConvertTy, Phi->getNumIncomingValues(),
-                                  Phi->getName() + ".tc", Phi);
+                                  Phi->getName() + ".tc", Phi->getIterator());
   // Pipe together all the PhiNodes.
   for (PHINode *Phi : PhiNodes) {
     PHINode *NewPhi = cast<PHINode>(ValMap[Phi]);

llvm/lib/CodeGen/ComplexDeinterleavingPass.cpp

@@ -1975,7 +1975,7 @@ Value *ComplexDeinterleavingGraph::replaceNode(IRBuilderBase &Builder,
     // It is filled later when the ReductionOperation is processed.
     auto *VTy = cast<VectorType>(Node->Real->getType());
     auto *NewVTy = VectorType::getDoubleElementsVectorType(VTy);
-    auto *NewPHI = PHINode::Create(NewVTy, 0, "", BackEdge->getFirstNonPHI());
+    auto *NewPHI = PHINode::Create(NewVTy, 0, "", BackEdge->getFirstNonPHIIt());
     OldToNewPHI[dyn_cast<PHINode>(Node->Real)] = NewPHI;
     ReplacementNode = NewPHI;
     break;

llvm/lib/Target/ARM/MVEGatherScatterLowering.cpp

@@ -1060,7 +1060,7 @@ bool MVEGatherScatterLowering::optimiseOffsets(Value *Offsets, BasicBlock *BB,
     NewPhi = Phi;
   } else {
     // There are other users -> create a new phi
-    NewPhi = PHINode::Create(Phi->getType(), 2, "NewPhi", Phi);
+    NewPhi = PHINode::Create(Phi->getType(), 2, "NewPhi", Phi->getIterator());
     // Copy the incoming values of the old phi
     NewPhi->addIncoming(Phi->getIncomingValue(IncrementingBlock == 1 ? 0 : 1),
                         Phi->getIncomingBlock(IncrementingBlock == 1 ? 0 : 1));

llvm/lib/Target/PowerPC/PPCBoolRetToInt.cpp

@@ -101,7 +101,7 @@ class PPCBoolRetToInt : public FunctionPass {
       // runOnUse.
       Value *Zero = Constant::getNullValue(IntTy);
       PHINode *Q =
-        PHINode::Create(IntTy, P->getNumIncomingValues(), P->getName(), P);
+        PHINode::Create(IntTy, P->getNumIncomingValues(), P->getName(), P->getIterator());
       for (unsigned i = 0; i < P->getNumOperands(); ++i)
         Q->addIncoming(Zero, P->getIncomingBlock(i));
       return Q;

llvm/lib/Target/RISCV/RISCVGatherScatterLowering.cpp

@@ -229,7 +229,7 @@ bool RISCVGatherScatterLowering::matchStridedRecurrence(Value *Index, Loop *L,
 
     // Build scalar phi and increment.
     BasePtr =
-        PHINode::Create(Start->getType(), 2, Phi->getName() + ".scalar", Phi);
+        PHINode::Create(Start->getType(), 2, Phi->getName() + ".scalar", Phi->getIterator());
     Inc = BinaryOperator::CreateAdd(BasePtr, Step, Inc->getName() + ".scalar",
                                     Inc);
     BasePtr->addIncoming(Start, Phi->getIncomingBlock(1 - IncrementingBlock));

llvm/lib/Target/X86/X86LowerAMXIntrinsics.cpp

@@ -116,7 +116,7 @@ BasicBlock *X86LowerAMXIntrinsics::createLoop(BasicBlock *Preheader,
   BranchInst::Create(Body, Header);
   BranchInst::Create(Latch, Body);
   PHINode *IV =
-      PHINode::Create(I16Ty, 2, Name + ".iv", Header->getTerminator());
+      PHINode::Create(I16Ty, 2, Name + ".iv", Header->getTerminator()->getIterator());
   IV->addIncoming(ConstantInt::get(I16Ty, 0), Preheader);
 
   B.SetInsertPoint(Latch);

polly/lib/CodeGen/BlockGenerators.cpp

@@ -1234,7 +1234,7 @@ PHINode *RegionGenerator::buildExitPHI(MemoryAccess *MA, LoopToScevMapT &LTS,
 
   PHINode *NewPHI = PHINode::Create(OrigPHI->getType(), Incoming.size(),
                                     "polly." + OrigPHI->getName(),
-                                    NewSubregionExit->getFirstNonPHI());
+                                    NewSubregionExit->getFirstNonPHIIt());
 
   // Add the incoming values to the PHI.
   for (auto &Pair : Incoming) {