[DLCov][NFC] Annotate intentionally-blank DebugLocs in existing code (#136192)

SLTozer · web-flow · commit aa8a1fa6f515 · 2025-06-11T17:42:10.000+01:00
Following the work in PR #107279, this patch applies the annotative DebugLocs, which indicate that a particular instruction is intentionally missing a location for a given reason, to existing sites in the compiler where their conditions apply. This is NFC in ordinary LLVM builds (each function `DebugLoc::getFoo()` is inlined as `DebugLoc()`), but marks the instruction in coverage-tracking builds so that it will be ignored by Debugify, allowing only real errors to be reported. From a developer standpoint, it also communicates the intentionality and reason for a missing DebugLoc. Some notes for reviewers: - The difference between `I->dropLocation()` and `I->setDebugLoc(DebugLoc::getDropped())` is that the former _may_ decide to keep some debug info alive, while the latter will always be empty; in this patch, I always used the latter (even if the former could technically be correct), because the former could result in some (barely) different output, and I'd prefer to keep this patch purely NFC. - I've generally documented the uses of `DebugLoc::getUnknown()`, with the exception of the vectorizers - in summary, they are a huge cause of dropped source locations, and I don't have the time or the domain knowledge currently to solve that, so I've plastered it all over them as a form of "fixme".
diff --git a/llvm/lib/Transforms/IPO/GlobalOpt.cpp b/llvm/lib/Transforms/IPO/GlobalOpt.cpp
@@ -1494,8 +1494,14 @@ processInternalGlobal(GlobalVariable *GV, const GlobalStatus &GS,
     // FIXME: Pass Global's alignment when globals have alignment
     AllocaInst *Alloca = new AllocaInst(ElemTy, DL.getAllocaAddrSpace(),
                                         nullptr, GV->getName(), FirstI);
-    if (!isa<UndefValue>(GV->getInitializer()))
-      new StoreInst(GV->getInitializer(), Alloca, FirstI);
+    Alloca->setDebugLoc(DebugLoc::getCompilerGenerated());
+    if (!isa<UndefValue>(GV->getInitializer())) {
+      auto *SI = new StoreInst(GV->getInitializer(), Alloca, FirstI);
+      // FIXME: We're localizing a global and creating a store instruction for
+      // the initial value of that global. Could we logically use the global
+      // variable's (if one exists) line for this?
+      SI->setDebugLoc(DebugLoc::getCompilerGenerated());
+    }
 
     GV->replaceAllUsesWith(Alloca);
     GV->eraseFromParent();
diff --git a/llvm/lib/Transforms/IPO/IROutliner.cpp b/llvm/lib/Transforms/IPO/IROutliner.cpp
@@ -730,7 +730,7 @@ static void moveFunctionData(Function &Old, Function &New,
       // other outlined instructions.
       if (!isa<CallInst>(&Val)) {
         // Remove the debug information for outlined functions.
-        Val.setDebugLoc(DebugLoc());
+        Val.setDebugLoc(DebugLoc::getDropped());
 
         // Loop info metadata may contain line locations. Update them to have no
         // value in the new subprogram since the outlined code could be from
@@ -1864,7 +1864,7 @@ replaceArgumentUses(OutlinableRegion &Region,
       Value *ValueOperand = SI->getValueOperand();
 
       StoreInst *NewI = cast<StoreInst>(I->clone());
-      NewI->setDebugLoc(DebugLoc());
+      NewI->setDebugLoc(DebugLoc::getDropped());
       BasicBlock *OutputBB = VBBIt->second;
       NewI->insertInto(OutputBB, OutputBB->end());
       LLVM_DEBUG(dbgs() << "Move store for instruction " << *I << " to "
diff --git a/llvm/lib/Transforms/InstCombine/InstCombinePHI.cpp b/llvm/lib/Transforms/InstCombine/InstCombinePHI.cpp
@@ -870,7 +870,14 @@ Instruction *InstCombinerImpl::foldPHIArgZextsIntoPHI(PHINode &Phi) {
     NewPhi->addIncoming(NewIncoming[I], Phi.getIncomingBlock(I));
 
   InsertNewInstBefore(NewPhi, Phi.getIterator());
-  return CastInst::CreateZExtOrBitCast(NewPhi, Phi.getType());
+  auto *CI = CastInst::CreateZExtOrBitCast(NewPhi, Phi.getType());
+
+  // We use a dropped location here because the new ZExt is necessarily a merge
+  // of ZExtInsts and at least one constant from incoming branches; the presence
+  // of the constant means we have no viable DebugLoc from that branch, and
+  // therefore we must use a dropped location.
+  CI->setDebugLoc(DebugLoc::getDropped());
+  return CI;
 }
 
 /// If all operands to a PHI node are the same "unary" operator and they all are
diff --git a/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp b/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
@@ -432,7 +432,8 @@ static bool processSwitch(SwitchInst *I, LazyValueInfo *LVI,
       BasicBlock *NewUnreachableBB =
           BasicBlock::Create(BB->getContext(), "default.unreachable",
                              BB->getParent(), DefaultDest);
-      new UnreachableInst(BB->getContext(), NewUnreachableBB);
+      auto *UI = new UnreachableInst(BB->getContext(), NewUnreachableBB);
+      UI->setDebugLoc(DebugLoc::getTemporary());
 
       DefaultDest->removePredecessor(BB);
       SI->setDefaultDest(NewUnreachableBB);
diff --git a/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp b/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp
@@ -1506,6 +1506,9 @@ bool IndVarSimplify::canonicalizeExitCondition(Loop *L) {
       auto *NewRHS = CastInst::Create(
           Instruction::Trunc, RHS, LHSOp->getType(), "",
           L->getLoopPreheader()->getTerminator()->getIterator());
+      // NewRHS is an operation that has been hoisted out of the loop, and
+      // therefore should have a dropped location.
+      NewRHS->setDebugLoc(DebugLoc::getDropped());
       ICmp->setOperand(Swapped ? 1 : 0, LHSOp);
       ICmp->setOperand(Swapped ? 0 : 1, NewRHS);
       // Samesign flag cannot be preserved after narrowing the compare.
diff --git a/llvm/lib/Transforms/Scalar/JumpThreading.cpp b/llvm/lib/Transforms/Scalar/JumpThreading.cpp
@@ -3001,8 +3001,10 @@ bool JumpThreadingPass::tryToUnfoldSelectInCurrBB(BasicBlock *BB) {
       continue;
     // Expand the select.
     Value *Cond = SI->getCondition();
-    if (!isGuaranteedNotToBeUndefOrPoison(Cond, nullptr, SI))
+    if (!isGuaranteedNotToBeUndefOrPoison(Cond, nullptr, SI)) {
       Cond = new FreezeInst(Cond, "cond.fr", SI->getIterator());
+      cast<FreezeInst>(Cond)->setDebugLoc(DebugLoc::getTemporary());
+    }
     MDNode *BranchWeights = getBranchWeightMDNode(*SI);
     Instruction *Term =
         SplitBlockAndInsertIfThen(Cond, SI, false, BranchWeights);
diff --git a/llvm/lib/Transforms/Scalar/LICM.cpp b/llvm/lib/Transforms/Scalar/LICM.cpp
@@ -2248,7 +2248,7 @@ bool llvm::promoteLoopAccessesToScalars(
     if (SawUnorderedAtomic)
       PreheaderLoad->setOrdering(AtomicOrdering::Unordered);
     PreheaderLoad->setAlignment(Alignment);
-    PreheaderLoad->setDebugLoc(DebugLoc());
+    PreheaderLoad->setDebugLoc(DebugLoc::getDropped());
     if (AATags && LoadIsGuaranteedToExecute)
       PreheaderLoad->setAAMetadata(AATags);
 
@@ -2808,6 +2808,7 @@ static bool hoistMulAddAssociation(Instruction &I, Loop &L,
     auto *NewBO =
         BinaryOperator::Create(Ins->getOpcode(), LHS, RHS,
                                Ins->getName() + ".reass", Ins->getIterator());
+    NewBO->setDebugLoc(DebugLoc::getDropped());
     NewBO->copyIRFlags(Ins);
     if (VariantOp == Ins)
       VariantOp = NewBO;
@@ -2864,6 +2865,7 @@ static bool hoistBOAssociation(Instruction &I, Loop &L,
 
   auto *NewBO = BinaryOperator::Create(
       Opcode, LV, Inv, BO->getName() + ".reass", BO->getIterator());
+  NewBO->setDebugLoc(DebugLoc::getDropped());
 
   if (Opcode == Instruction::FAdd || Opcode == Instruction::FMul) {
     // Intersect FMF flags for FADD and FMUL.
diff --git a/llvm/lib/Transforms/Scalar/LoopLoadElimination.cpp b/llvm/lib/Transforms/Scalar/LoopLoadElimination.cpp
@@ -442,14 +442,15 @@ class LoadEliminationForLoop {
     assert(PH && "Preheader should exist!");
     Value *InitialPtr = SEE.expandCodeFor(PtrSCEV->getStart(), Ptr->getType(),
                                           PH->getTerminator());
-    Value *Initial =
+    Instruction *Initial =
         new LoadInst(Cand.Load->getType(), InitialPtr, "load_initial",
                      /* isVolatile */ false, Cand.Load->getAlign(),
                      PH->getTerminator()->getIterator());
     // We don't give any debug location to Initial, because it is inserted
     // into the loop's preheader. A debug location inside the loop will cause
     // a misleading stepping when debugging. The test update-debugloc-store
     // -forwarded.ll checks this.
+    Initial->setDebugLoc(DebugLoc::getDropped());
 
     PHINode *PHI = PHINode::Create(Initial->getType(), 2, "store_forwarded");
     PHI->insertBefore(L->getHeader()->begin());
diff --git a/llvm/lib/Transforms/Scalar/SimpleLoopUnswitch.cpp b/llvm/lib/Transforms/Scalar/SimpleLoopUnswitch.cpp
@@ -274,6 +274,7 @@ static void buildPartialUnswitchConditionalBranch(
     BasicBlock &UnswitchedSucc, BasicBlock &NormalSucc, bool InsertFreeze,
     const Instruction *I, AssumptionCache *AC, const DominatorTree &DT) {
   IRBuilder<> IRB(&BB);
+  IRB.SetCurrentDebugLocation(DebugLoc::getCompilerGenerated());
 
   SmallVector<Value *> FrozenInvariants;
   for (Value *Inv : Invariants) {
@@ -330,6 +331,7 @@ static void buildPartialInvariantUnswitchConditionalBranch(
   }
 
   IRBuilder<> IRB(&BB);
+  IRB.SetCurrentDebugLocation(DebugLoc::getCompilerGenerated());
   Value *Cond = VMap[ToDuplicate[0]];
   IRB.CreateCondBr(Cond, Direction ? &UnswitchedSucc : &NormalSucc,
                    Direction ? &NormalSucc : &UnswitchedSucc);
@@ -2369,6 +2371,7 @@ static void unswitchNontrivialInvariants(
         // BI (`dyn_cast<BranchInst>(TI)`) is an in-loop instruction hoisted
         // out of the loop.
         Cond = new FreezeInst(Cond, Cond->getName() + ".fr", BI->getIterator());
+        cast<Instruction>(Cond)->setDebugLoc(DebugLoc::getDropped());
       }
       BI->setCondition(Cond);
       DTUpdates.push_back({DominatorTree::Insert, SplitBB, ClonedPH});
diff --git a/llvm/lib/Transforms/Scalar/TailRecursionElimination.cpp b/llvm/lib/Transforms/Scalar/TailRecursionElimination.cpp
@@ -515,7 +515,8 @@ void TailRecursionEliminator::createTailRecurseLoopHeader(CallInst *CI) {
   BasicBlock *NewEntry = BasicBlock::Create(F.getContext(), "", &F, HeaderBB);
   NewEntry->takeName(HeaderBB);
   HeaderBB->setName("tailrecurse");
-  BranchInst::Create(HeaderBB, NewEntry);
+  auto *BI = BranchInst::Create(HeaderBB, NewEntry);
+  BI->setDebugLoc(DebugLoc::getCompilerGenerated());
   // If the new branch preserves the debug location of CI, it could result in
   // misleading stepping, if CI is located in a conditional branch.
   // So, here we don't give any debug location to the new branch.
@@ -801,6 +802,7 @@ void TailRecursionEliminator::cleanupAndFinalize() {
         SelectInst *SI =
             SelectInst::Create(RetKnownPN, RetPN, RI->getOperand(0),
                                "current.ret.tr", RI->getIterator());
+        SI->setDebugLoc(DebugLoc::getCompilerGenerated());
         RetSelects.push_back(SI);
         RI->setOperand(0, SI);
       }
diff --git a/llvm/lib/Transforms/Utils/InlineFunction.cpp b/llvm/lib/Transforms/Utils/InlineFunction.cpp
@@ -1775,6 +1775,7 @@ static Value *HandleByValArgument(Type *ByValType, Value *Arg,
   AllocaInst *NewAlloca =
       new AllocaInst(ByValType, Arg->getType()->getPointerAddressSpace(),
                      nullptr, Alignment, Arg->getName());
+  NewAlloca->setDebugLoc(DebugLoc::getCompilerGenerated());
   NewAlloca->insertBefore(Caller->begin()->begin());
   IFI.StaticAllocas.push_back(NewAlloca);
 
@@ -3258,6 +3259,8 @@ llvm::InlineResult llvm::InlineFunction(CallBase &CB, InlineFunctionInfo &IFI,
 
     // Add an unconditional branch to make this look like the CallInst case...
     CreatedBranchToNormalDest = BranchInst::Create(II->getNormalDest(), CB.getIterator());
+    // We intend to replace this DebugLoc with another later.
+    CreatedBranchToNormalDest->setDebugLoc(DebugLoc::getTemporary());
 
     // Split the basic block.  This guarantees that no PHI nodes will have to be
     // updated due to new incoming edges, and make the invoke case more
@@ -3359,6 +3362,12 @@ llvm::InlineResult llvm::InlineFunction(CallBase &CB, InlineFunctionInfo &IFI,
     Returns[0]->eraseFromParent();
     ReturnBB->eraseFromParent();
   } else if (!CB.use_empty()) {
+    // In this case there are no returns to use, so there is no clear source
+    // location for the "return".
+    // FIXME: It may be correct to use the scope end line of the function here,
+    // since this likely means we are falling out of the function.
+    if (CreatedBranchToNormalDest)
+      CreatedBranchToNormalDest->setDebugLoc(DebugLoc::getUnknown());
     // No returns, but something is using the return value of the call.  Just
     // nuke the result.
     CB.replaceAllUsesWith(PoisonValue::get(CB.getType()));
diff --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp
@@ -3127,7 +3127,8 @@ static bool markAliveBlocks(Function &F,
           BasicBlock *UnreachableNormalDest = BasicBlock::Create(
               Ctx, OrigNormalDest->getName() + ".unreachable",
               II->getFunction(), OrigNormalDest);
-          new UnreachableInst(Ctx, UnreachableNormalDest);
+          auto *UI = new UnreachableInst(Ctx, UnreachableNormalDest);
+          UI->setDebugLoc(DebugLoc::getTemporary());
           II->setNormalDest(UnreachableNormalDest);
           if (DTU)
             DTU->applyUpdates(
diff --git a/llvm/lib/Transforms/Utils/SCCPSolver.cpp b/llvm/lib/Transforms/Utils/SCCPSolver.cpp
@@ -348,7 +348,9 @@ bool SCCPSolver::removeNonFeasibleEdges(BasicBlock *BB, DomTreeUpdater &DTU,
         NewUnreachableBB =
             BasicBlock::Create(DefaultDest->getContext(), "default.unreachable",
                                DefaultDest->getParent(), DefaultDest);
-        new UnreachableInst(DefaultDest->getContext(), NewUnreachableBB);
+        auto *UI =
+            new UnreachableInst(DefaultDest->getContext(), NewUnreachableBB);
+        UI->setDebugLoc(DebugLoc::getTemporary());
       }
 
       DefaultDest->removePredecessor(BB);
diff --git a/llvm/lib/Transforms/Utils/SSAUpdater.cpp b/llvm/lib/Transforms/Utils/SSAUpdater.cpp
@@ -318,6 +318,11 @@ class SSAUpdaterTraits<SSAUpdater> {
                                SSAUpdater *Updater) {
     PHINode *PHI =
         PHINode::Create(Updater->ProtoType, NumPreds, Updater->ProtoName);
+    // FIXME: Ordinarily we don't care about or try to assign DebugLocs to PHI
+    // nodes, but loop optimizations may try to use a PHI node as a DebugLoc
+    // source (e.g. if this is an induction variable), and it's not clear what
+    // location we could attach here, so mark this unknown for now.
+    PHI->setDebugLoc(DebugLoc::getUnknown());
     PHI->insertBefore(BB->begin());
     return PHI;
   }
diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -1137,7 +1137,7 @@ static void cloneInstructionsIntoPredecessorBlockAndUpdateSSAUses(
         // branch, drop it. When we fold the bonus instructions we want to make
         // sure we reset their debug locations in order to avoid stepping on
         // dead code caused by folding dead branches.
-        NewBonusInst->setDebugLoc(DebugLoc());
+        NewBonusInst->setDebugLoc(DebugLoc::getDropped());
       } else if (const DebugLoc &DL = NewBonusInst->getDebugLoc()) {
         mapAtomInstance(DL, VMap);
       }
@@ -2821,7 +2821,8 @@ static void mergeCompatibleInvokesImpl(ArrayRef<InvokeInst *> Invokes,
       // so just form a new block with unreachable terminator.
       BasicBlock *MergedNormalDest = BasicBlock::Create(
           Ctx, II0BB->getName() + ".cont", Func, InsertBeforeBlock);
-      new UnreachableInst(Ctx, MergedNormalDest);
+      auto *UI = new UnreachableInst(Ctx, MergedNormalDest);
+      UI->setDebugLoc(DebugLoc::getTemporary());
       MergedInvoke->setNormalDest(MergedNormalDest);
     }
 
@@ -3389,7 +3390,7 @@ bool SimplifyCFGOpt::speculativelyExecuteBB(BranchInst *BI,
     if (!SpeculatedStoreValue || &I != SpeculatedStore) {
       // Don't update the DILocation of dbg.assign intrinsics.
       if (!isa<DbgAssignIntrinsic>(&I))
-        I.setDebugLoc(DebugLoc());
+        I.setDebugLoc(DebugLoc::getDropped());
     }
     I.dropUBImplyingAttrsAndMetadata();
 
@@ -5707,7 +5708,8 @@ static void createUnreachableSwitchDefault(SwitchInst *Switch,
   BasicBlock *NewDefaultBlock = BasicBlock::Create(
       BB->getContext(), BB->getName() + ".unreachabledefault", BB->getParent(),
       OrigDefaultBlock);
-  new UnreachableInst(Switch->getContext(), NewDefaultBlock);
+  auto *UI = new UnreachableInst(Switch->getContext(), NewDefaultBlock);
+  UI->setDebugLoc(DebugLoc::getTemporary());
   Switch->setDefaultDest(&*NewDefaultBlock);
   if (DTU) {
     SmallVector<DominatorTree::UpdateType, 2> Updates;
diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorizationPlanner.h b/llvm/lib/Transforms/Vectorize/LoopVectorizationPlanner.h
@@ -153,7 +153,7 @@ class VPBuilder {
   VPInstruction *createNaryOp(unsigned Opcode, ArrayRef<VPValue *> Operands,
                               Instruction *Inst = nullptr,
                               const Twine &Name = "") {
-    DebugLoc DL;
+    DebugLoc DL = DebugLoc::getUnknown();
     if (Inst)
       DL = Inst->getDebugLoc();
     VPInstruction *NewVPInst = createInstruction(Opcode, Operands, DL, Name);
@@ -165,7 +165,8 @@ class VPBuilder {
     return createInstruction(Opcode, Operands, DL, Name);
   }
   VPInstruction *createNaryOp(unsigned Opcode, ArrayRef<VPValue *> Operands,
-                              const VPIRFlags &Flags, DebugLoc DL = {},
+                              const VPIRFlags &Flags,
+                              DebugLoc DL = DebugLoc::getUnknown(),
                               const Twine &Name = "") {
     return tryInsertInstruction(
         new VPInstruction(Opcode, Operands, Flags, DL, Name));
@@ -174,45 +175,51 @@ class VPBuilder {
   VPInstruction *createNaryOp(unsigned Opcode,
                               std::initializer_list<VPValue *> Operands,
                               Type *ResultTy, const VPIRFlags &Flags = {},
-                              DebugLoc DL = {}, const Twine &Name = "") {
+                              DebugLoc DL = DebugLoc::getUnknown(),
+                              const Twine &Name = "") {
     return tryInsertInstruction(
         new VPInstructionWithType(Opcode, Operands, ResultTy, Flags, DL, Name));
   }
 
   VPInstruction *createOverflowingOp(unsigned Opcode,
                                      std::initializer_list<VPValue *> Operands,
                                      VPRecipeWithIRFlags::WrapFlagsTy WrapFlags,
-                                     DebugLoc DL = {}, const Twine &Name = "") {
+                                     DebugLoc DL = DebugLoc::getUnknown(),
+                                     const Twine &Name = "") {
     return tryInsertInstruction(
         new VPInstruction(Opcode, Operands, WrapFlags, DL, Name));
   }
 
-  VPValue *createNot(VPValue *Operand, DebugLoc DL = {},
+  VPValue *createNot(VPValue *Operand, DebugLoc DL = DebugLoc::getUnknown(),
                      const Twine &Name = "") {
     return createInstruction(VPInstruction::Not, {Operand}, DL, Name);
   }
 
-  VPValue *createAnd(VPValue *LHS, VPValue *RHS, DebugLoc DL = {},
+  VPValue *createAnd(VPValue *LHS, VPValue *RHS,
+                     DebugLoc DL = DebugLoc::getUnknown(),
                      const Twine &Name = "") {
     return createInstruction(Instruction::BinaryOps::And, {LHS, RHS}, DL, Name);
   }
 
-  VPValue *createOr(VPValue *LHS, VPValue *RHS, DebugLoc DL = {},
+  VPValue *createOr(VPValue *LHS, VPValue *RHS,
+                    DebugLoc DL = DebugLoc::getUnknown(),
                     const Twine &Name = "") {
 
     return tryInsertInstruction(new VPInstruction(
         Instruction::BinaryOps::Or, {LHS, RHS},
         VPRecipeWithIRFlags::DisjointFlagsTy(false), DL, Name));
   }
 
-  VPValue *createLogicalAnd(VPValue *LHS, VPValue *RHS, DebugLoc DL = {},
+  VPValue *createLogicalAnd(VPValue *LHS, VPValue *RHS,
+                            DebugLoc DL = DebugLoc::getUnknown(),
                             const Twine &Name = "") {
     return tryInsertInstruction(
         new VPInstruction(VPInstruction::LogicalAnd, {LHS, RHS}, DL, Name));
   }
 
   VPValue *createSelect(VPValue *Cond, VPValue *TrueVal, VPValue *FalseVal,
-                        DebugLoc DL = {}, const Twine &Name = "",
+                        DebugLoc DL = DebugLoc::getUnknown(),
+                        const Twine &Name = "",
                         std::optional<FastMathFlags> FMFs = std::nullopt) {
     auto *Select =
         FMFs ? new VPInstruction(Instruction::Select, {Cond, TrueVal, FalseVal},
@@ -226,20 +233,23 @@ class VPBuilder {
   /// and \p B.
   /// TODO: add createFCmp when needed.
   VPValue *createICmp(CmpInst::Predicate Pred, VPValue *A, VPValue *B,
-                      DebugLoc DL = {}, const Twine &Name = "") {
+                      DebugLoc DL = DebugLoc::getUnknown(),
+                      const Twine &Name = "") {
     assert(Pred >= CmpInst::FIRST_ICMP_PREDICATE &&
            Pred <= CmpInst::LAST_ICMP_PREDICATE && "invalid predicate");
     return tryInsertInstruction(
         new VPInstruction(Instruction::ICmp, {A, B}, Pred, DL, Name));
   }
 
-  VPInstruction *createPtrAdd(VPValue *Ptr, VPValue *Offset, DebugLoc DL = {},
+  VPInstruction *createPtrAdd(VPValue *Ptr, VPValue *Offset,
+                              DebugLoc DL = DebugLoc::getUnknown(),
                               const Twine &Name = "") {
     return tryInsertInstruction(
         new VPInstruction(VPInstruction::PtrAdd, {Ptr, Offset},
                           GEPNoWrapFlags::none(), DL, Name));
   }
-  VPValue *createInBoundsPtrAdd(VPValue *Ptr, VPValue *Offset, DebugLoc DL = {},
+  VPValue *createInBoundsPtrAdd(VPValue *Ptr, VPValue *Offset,
+                                DebugLoc DL = DebugLoc::getUnknown(),
                                 const Twine &Name = "") {
     return tryInsertInstruction(
         new VPInstruction(VPInstruction::PtrAdd, {Ptr, Offset},
diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -772,7 +772,7 @@ class EpilogueVectorizerEpilogueLoop : public InnerLoopAndEpilogueVectorizer {
 /// Look for a meaningful debug location on the instruction or its operands.
 static DebugLoc getDebugLocFromInstOrOperands(Instruction *I) {
   if (!I)
-    return DebugLoc();
+    return DebugLoc::getUnknown();
 
   DebugLoc Empty;
   if (I->getDebugLoc() != Empty)
@@ -1881,13 +1881,15 @@ class GeneratedRTChecks {
     if (SCEVCheckBlock) {
       SCEVCheckBlock->getTerminator()->moveBefore(
           Preheader->getTerminator()->getIterator());
-      new UnreachableInst(Preheader->getContext(), SCEVCheckBlock);
+      auto *UI = new UnreachableInst(Preheader->getContext(), SCEVCheckBlock);
+      UI->setDebugLoc(DebugLoc::getTemporary());
       Preheader->getTerminator()->eraseFromParent();
     }
     if (MemCheckBlock) {
       MemCheckBlock->getTerminator()->moveBefore(
           Preheader->getTerminator()->getIterator());
-      new UnreachableInst(Preheader->getContext(), MemCheckBlock);
+      auto *UI = new UnreachableInst(Preheader->getContext(), MemCheckBlock);
+      UI->setDebugLoc(DebugLoc::getTemporary());
       Preheader->getTerminator()->eraseFromParent();
     }
 
diff --git a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
diff --git a/llvm/lib/Transforms/Vectorize/VPlan.h b/llvm/lib/Transforms/Vectorize/VPlan.h
