[DebugInfo][RemoveDIs] Use iterators to insert everywhere (#102003)

These are the final few places in LLVM where we use instruction pointers
to identify the position that we're inserting something. We're trying to
get away from that with a view to deprecating those methods, thus use
iterators in all these places. I believe they're all debug-info safe.

The sketchiest part is the ExtractValueInst copy constructor, where we
cast nullptr to a BasicBlock pointer, so that we take the non-default
insert-into-no-block path for instruction insertion, instead of the
default nullptr-instruction path for UnaryInstruction. Such a hack is
necessary until we get rid of the instruction constructor entirely.

Author: jmorse

llvm/lib/IR/Instructions.cpp

@@ -2484,8 +2484,9 @@ void ExtractValueInst::init(ArrayRef<unsigned> Idxs, const Twine &Name) {
 }
 
 ExtractValueInst::ExtractValueInst(const ExtractValueInst &EVI)
-  : UnaryInstruction(EVI.getType(), ExtractValue, EVI.getOperand(0)),
-    Indices(EVI.Indices) {
+    : UnaryInstruction(EVI.getType(), ExtractValue, EVI.getOperand(0),
+                       (BasicBlock *)nullptr),
+      Indices(EVI.Indices) {
   SubclassOptionalData = EVI.SubclassOptionalData;
 }
 

llvm/lib/Transforms/IPO/ExpandVariadics.cpp

@@ -809,7 +809,7 @@ bool ExpandVariadics::expandCall(Module &M, IRBuilder<> &Builder, CallBase *CB,
     Value *Dst = NF ? NF : CI->getCalledOperand();
     FunctionType *NFTy = inlinableVariadicFunctionType(M, VarargFunctionType);
 
-    NewCB = CallInst::Create(NFTy, Dst, Args, OpBundles, "", CI);
+    NewCB = CallInst::Create(NFTy, Dst, Args, OpBundles, "", CI->getIterator());
 
     CallInst::TailCallKind TCK = CI->getTailCallKind();
     assert(TCK != CallInst::TCK_MustTail);

llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp

@@ -690,8 +690,8 @@ class RuntimeCallInserter {
       if (EHPad && EHPad->isEHPad()) {
         // Replace CI with a clone with an added funclet OperandBundle
         OperandBundleDef OB("funclet", EHPad);
-        auto *NewCall =
-            CallBase::addOperandBundle(CI, LLVMContext::OB_funclet, OB, CI);
+        auto *NewCall = CallBase::addOperandBundle(CI, LLVMContext::OB_funclet,
+                                                   OB, CI->getIterator());
         NewCall->copyMetadata(*CI);
         CI->replaceAllUsesWith(NewCall);
         CI->eraseFromParent();

llvm/lib/Transforms/Scalar/LICM.cpp

@@ -2767,8 +2767,9 @@ static bool hoistMulAddAssociation(Instruction &I, Loop &L,
     unsigned OpIdx = U->getOperandNo();
     auto *LHS = OpIdx == 0 ? Mul : Ins->getOperand(0);
     auto *RHS = OpIdx == 1 ? Mul : Ins->getOperand(1);
-    auto *NewBO = BinaryOperator::Create(Ins->getOpcode(), LHS, RHS,
-                                         Ins->getName() + ".reass", Ins);
+    auto *NewBO =
+        BinaryOperator::Create(Ins->getOpcode(), LHS, RHS,
+                               Ins->getName() + ".reass", Ins->getIterator());
     NewBO->copyIRFlags(Ins);
     if (VariantOp == Ins)
       VariantOp = NewBO;
@@ -2822,9 +2823,9 @@ static bool hoistBOAssociation(Instruction &I, Loop &L,
   assert(Preheader && "Loop is not in simplify form?");
 
   auto *Inv = BinaryOperator::Create(Opcode, C1, C2, "invariant.op",
-                                     Preheader->getTerminator());
-  auto *NewBO =
-      BinaryOperator::Create(Opcode, LV, Inv, BO->getName() + ".reass", BO);
+                                     Preheader->getTerminator()->getIterator());
+  auto *NewBO = BinaryOperator::Create(
+      Opcode, LV, Inv, BO->getName() + ".reass", BO->getIterator());
 
   // Copy NUW for ADDs if both instructions have it.
   if (Opcode == Instruction::Add && BO->hasNoUnsignedWrap() &&

llvm/lib/Transforms/Utils/PromoteMemoryToRegister.cpp

@@ -460,7 +460,7 @@ static void convertMetadataToAssumes(LoadInst *LI, Value *Val,
     LLVMContext &Ctx = LI->getContext();
     new StoreInst(ConstantInt::getTrue(Ctx),
                   PoisonValue::get(PointerType::getUnqual(Ctx)),
-                  /*isVolatile=*/false, Align(1), LI);
+                  /*isVolatile=*/false, Align(1), LI->getIterator());
     return;
   }
 

llvm/lib/Transforms/Vectorize/LoopVectorize.cpp

@@ -2632,8 +2632,9 @@ PHINode *InnerLoopVectorizer::createInductionResumeValue(
   }
 
   // Create phi nodes to merge from the  backedge-taken check block.
-  PHINode *BCResumeVal = PHINode::Create(OrigPhi->getType(), 3, "bc.resume.val",
-                                         LoopScalarPreHeader->getFirstNonPHI());
+  PHINode *BCResumeVal =
+      PHINode::Create(OrigPhi->getType(), 3, "bc.resume.val",
+                      LoopScalarPreHeader->getFirstNonPHIIt());
   // Copy original phi DL over to the new one.
   BCResumeVal->setDebugLoc(OrigPhi->getDebugLoc());