[llvm] [DirectX] Bug fix for Data Scalarization crash (PR #118426)

[Justin Bogner via llvm-commits]

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@@ -321,6 +321,18 @@ static void collectElements(Constant *Init,
     Elements.push_back(Init);
     return;
   }
+  auto *LLVMArrayType = dyn_cast<ArrayType>(Init->getType());
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bogner wrote:

This should either be `cast<ArrayType>` (since the cast can't fail) or we should do the `dyn_cast` and check for null above instead of `isa`.

This is also kind of a weird name - I think `ArrayTy` is the usual abbreviation.

https://github.com/llvm/llvm-project/pull/118426