of Value deletions and RAUWs, instead of relying on ScalarEvolution's
Scalars map being notified, as that's complicated at best, and
insufficient in general.
This means SCEVUnknown needs a non-trivial destructor, so introduce
a mechanism to allow ScalarEvolution to locate all the SCEVUnknowns.
llvm-svn: 110086
extend it to handle the case where multiple RAUWs affect a single
SCEVUnknown.
Add a ScalarEvolution unittest to test for this situation.
llvm-svn: 109705