[PATCH] D58088: [adt] Add raw_pointer_iterator to iterate over std::unique_ptr<> collections

Wed Feb 20 14:07:57 PST 2019

dblaikie added a comment.

In D58088#1404769 <https://reviews.llvm.org/D58088#1404769>, @dsanders wrote:

> I just noticed a big simplification that doesn't need C++20 features or new classes. This:
>
>   template <typename WrappedIteratorT,
>             typename T1 = typename std::remove_reference<decltype(**std::declval<WrappedIteratorT>())>::type,
>             typename T2 = typename std::add_pointer<T1>::type>
>   using raw_pointer_iterator = pointer_iterator<pointee_iterator<WrappedIteratorT, T1>, T2>;
>
>
> is functionally equivalent to the raw_pointer_iterator in this patch. pointee_iterator derefs the unique_ptr, while pointer_iterator produces the raw_pointer. If that version sounds good to you then I think it makes sense to revert the llvm::to_address() patch, switch to this implementation and fold this into the GISel Combiner patch as at that point it's too trivial to warrant a dedicated patch. Does that sound good?

Beyond probably some annoying compile-time complexity/overhead (& maybe similar debugging confusion with the extra layers of abstraction) - I'm guessing this wouldn't support null pointers (because pointee_iterator probably dereferences unconditionally?) which would be a bit problematic, I'd reckon?

Repository:
  rL LLVM

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https://reviews.llvm.org/D58088