[PATCH] D49384: [IPSCCP] Do not zap return if the return value is overdefined at any call site.

[Davide Italiano via Phabricator via llvm-commits]

davide added a comment.

FWIW, my take is that we should kill `ResolvedUndefsIn` (as already pointed by Eli, and probably me, and others in the past).
My take is that the benefit of having a forth lattice state is really little compared to the amount of effort we had to put to fix bugs.
If somebody is willing to take the time to do the work I'd rather zap away undef from the lattice and see how many constant we lose (and what's the runtime cost). But I understand this is a fair amount of work. That said, I think I like Eli's proof of concept a little better than this, so I'm happy if you want to pursue that path, Florian.


https://reviews.llvm.org/D49384