[LSV] Don't assume that loads/stores appear in address order in the BB.
Summary:
getVectorizablePrefix previously didn't work properly in the face of
aliasing loads/stores. It unwittingly assumed that the loads/stores
appeared in the BB in address order. If they didn't, it would do the
wrong thing.
Reviewers: asbirlea, tstellarAMD
Subscribers: arsenm, llvm-commits, mzolotukhin
Differential Revision: https://reviews.llvm.org/D22535
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@276072
91177308-0d34-0410-b5e6-
96231b3b80d8