[DebugInfo][LoopLoadElim] Missing debug location updates

[Apochens]

Missing debug location updates for new instructions at LoopLoadElimination-L447, -L452, -L466.

->  Value *Initial =
        new LoadInst(Cand.Load->getType(), InitialPtr, "load_initial",
                     /* isVolatile */ false, Cand.Load->getAlign(),
                     PH->getTerminator()->getIterator());

->  PHINode *PHI = PHINode::Create(Initial->getType(), 2, "store_forwarded");
    PHI->insertBefore(L->getHeader()->begin());
    PHI->addIncoming(Initial, PH);

    ...

    Value *StoreValue = Cand.Store->getValueOperand();
    if (LoadType != StoreType)
->    StoreValue = CastInst::CreateBitOrPointerCast(StoreValue, LoadType,
                                                    "store_forward_cast",
                                                    Cand.Store->getIterator());

    PHI->addIncoming(StoreValue, L->getLoopLatch());

    Cand.Load->replaceAllUsesWith(PHI);

I'll give a patch for this later.

[llvmbot]

@llvm/issue-subscribers-debuginfo

Author: Shan Huang (Apochens)

Missing debug location updates for new instructions at LoopLoadElimination[-L447](https://github.com/llvm/llvm-project/blob/e62ce1f8842cca36eb14126d79dcca0a85bf6d36/llvm/lib/Transforms/Scalar/LoopLoadElimination.cpp#L447), [-L452](https://github.com/llvm/llvm-project/blob/e62ce1f8842cca36eb14126d79dcca0a85bf6d36/llvm/lib/Transforms/Scalar/LoopLoadElimination.cpp#L452), [-L466](https://github.com/llvm/llvm-project/blob/e62ce1f8842cca36eb14126d79dcca0a85bf6d36/llvm/lib/Transforms/Scalar/LoopLoadElimination.cpp#L466).

->  Value *Initial =
        new LoadInst(Cand.Load->getType(), InitialPtr, "load_initial",
                     /* isVolatile */ false, Cand.Load->getAlign(),
                     PH->getTerminator()->getIterator());

->  PHINode *PHI = PHINode::Create(Initial->getType(), 2, "store_forwarded");
    PHI->insertBefore(L->getHeader()->begin());
    PHI->addIncoming(Initial, PH);

    ...

    Value *StoreValue = Cand.Store->getValueOperand();
    if (LoadType != StoreType)
->    StoreValue = CastInst::CreateBitOrPointerCast(StoreValue, LoadType,
                                                    "store_forward_cast",
                                                    Cand.Store->getIterator());

    PHI->addIncoming(StoreValue, L->getLoopLatch());

    Cand.Load->replaceAllUsesWith(PHI);

I'll give a patch for this later.