[Hexagon] Improve patterns with stack-based addressing

- Treat bitwise OR with a frame index as an ADD wherever possible, fold it
  into addressing mode.
- Extend patterns for memops to allow memops with frame indexes as address
  operands.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@275569 91177308-0d34-0410-b5e6-96231b3b80d8
8 files changed