[MemDep] Use PhiValuesAnalysis to improve alias analysis results

This is being done in order to make GVN able to better optimize certain inputs.
MemDep doesn't use PhiValues directly, but does need to notifiy it when things
get invalidated.

Differential Revision: https://reviews.llvm.org/D48489


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@338384 91177308-0d34-0410-b5e6-96231b3b80d8
9 files changed