[llvm-commits] [pr12979][patch/rfc] Clear nsw/nuw in gvn

[Daniel Berlin]

>
> Metadata nodes are uniqued. When merging two files of the same language, the
> type trees will merge as well, and they will then share the same root and
> potentially many sub-trees as well.
Okay

> So I believe the reasoning I presented is correct.

Oh, i don't disagree that least common ancestor is correct, it's what
we do in GCC.  I'm just pointing out the semantic you are suggesting
(loads in two different tbaa trees don't alias) is exactly the
opposite of what the semantic the language guide says :)

So if we want to go with that, we should update the language guide to
state that we don't consider things from two different tbaa trees to
alias.