[PATCH] D35918: [GVNHoist] Factor out reachability to search for anticipable instructions quickly

[Jakub Kuderski via Phabricator via llvm-commits]

kuhar added a comment.

@dberlin, @hiraditya

In https://reviews.llvm.org/D35918#822192, @dberlin wrote:

> The graph always has one root, virtual or not.
>  Once kuba's latest patch is committed, it will *always* be virtual, actually.


That's actually already the case upstream since r309146 (https://reviews.llvm.org/D35597).
https://github.com/llvm-mirror/llvm/blob/22072158f353cc89a7821b13a7c3e99daa5be464/include/llvm/Support/GenericDomTreeConstruction.h#L263
https://github.com/llvm-mirror/llvm/blob/22072158f353cc89a7821b13a7c3e99daa5be464/include/llvm/Support/GenericDomTreeConstruction.h#L307


https://reviews.llvm.org/D35918