[SelectionDAG][X86][SystemZ] Add a generic nonvolatile_store/nonvolatile_load pattern fragment in TargetSelectionDAG.td

Differential Revision: https://reviews.llvm.org/D50358

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@339156 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed