Recommit r333268: [IPSCCP] Use PredicateInfo to propagate facts from cmp instructions.
r337828 resolves a PredicateInfo issue with unnamed types.
This patch updates IPSCCP to use PredicateInfo to propagate
facts to true branches predicated by EQ and to false branches
predicated by NE.
As a follow up, we should be able to extend it to also propagate additional
facts about nonnull.
Reviewers: davide, mssimpso, dberlin, efriedma
Reviewed By: davide, dberlin