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

[Aditya Kumar via Phabricator via llvm-commits]

hiraditya added a comment.

In https://reviews.llvm.org/D35918#829175, @kuhar wrote:

> @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


Can you illustrate how to perform a DFS walk on a post-dom tree with your patch. Also, how would I get the (virtual) root node of post-dom tree.


https://reviews.llvm.org/D35918