[llvm-dev] How to deal with accidental directory tree deletes, downstream?

[via llvm-dev]

Hello fellow downstream residents,

I see that r358546 accidentally deleted an entire subtree, which was
reverted in r358552.  This of course caused a big merge conflict in 
our local repo, and internally we've been debating tactics for dealing 
with it, hopefully without losing our original history.

Has anyone else handled this in a way that they are happy with?  We
found a StackOverflow post that is potentially helpful:
https://stackoverflow.com/questions/44990103/how-to-undelete-file-in-git-and-keep-his-original-blame-history
Doing this on our local copy of the upstream repo means we would not
have an exact copy anymore, which seems like a Bad Idea.

Is there a smooth way to resolve the merge conflict that does *not*
delete our local tree? I suppose we can somehow not accept the
accidental deletes, and then when we run forward to r358552 it will
decide we already have those files and it will Just Work?

Tips and hints welcome.
Thanks,
--paulr