[PATCH] D38586: SLPVectorizer.cpp: Ensure SLPVectorizer can visit each block by dominated order

[Davide Italiano via Phabricator via llvm-commits]

davide added a comment.

In https://reviews.llvm.org/D38586#891283, @chapuni wrote:

> The test added. This comes from EmitAtomicUpdateValue() in CGAtomic.cpp.
>  I confirmed it fails on both libstdc++ and libc++ to me.
>
> I will attempt to get rid of O(N^2) there, but I think it'd not be big deal unless preds exceeded hundreds.


I really think we should try to at least make an attempt to get rid of the O(N^2) behaviour as it doesn't seem terribly complicated to do so _and_ it may bite us in the future in many unexpected ways. The test seems fine, but you can probably clean it up a bit (and run metarenamer on it for shorter names)


Repository:
  rL LLVM

https://reviews.llvm.org/D38586