Remove the expensive BitVector::operator~().

Returning a temporary BitVector is very expensive. If you must, create
the temporary explicitly: Use BitVector(A).flip() instead of ~A.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156768 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed