[PATCH] D102255: [SelectionDAG] Generate scoped AA metadata when lowering memcpy.

[Jeroen Dobbelaere via Phabricator via llvm-commits]

jeroen.dobbelaere added a comment.

In D102255#2755372 <https://reviews.llvm.org/D102255#2755372>, @nikic wrote:

> I agree that rescheduling the loads/stores is correct even if src and dst are equal. However, the metadata itself is still incorrect: It will claim that the loads/stores are NoAlias, even though they are actually MustAlias.

The proposed version introduces 2 scopes, assigning all store to one scope and all loads to another.

I order to avoid the `MustAlias` vs `NoAlias` problem, we could introduce a scope per load-store pair. Of course, that might be a lot of extra scopes..


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https://reviews.llvm.org/D102255