Peter Collingbourne 9947c49812 [dfsan] Introduce further optimization to reduce the number of union queries.
Specifically, do not compute a union if it is statically known that one
shadow set subsumes the other.

llvm-svn: 213100
2014-07-15 22:13:19 +00:00
..
2014-07-08 00:03:11 +00:00