[LV] Interleaved access vectorization: fix computing new alias info

As a new access is generated spanning across multiple fields, we need to
propagate alias info from all the fields to form the most generic alias info.

rdar://35602528

Differential Revision: https://reviews.llvm.org/D40617

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@319979 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed