Recommit "[SelectionDAG][RISCV] Add very basic PromoteIntegerResult/Op support for VP_SIGN/ZERO_EXTEND."
I have fixed an existing DAGCombiner bug that caused the previous assertion failure.
See
7163539466d7e8930416e55dd9fd29891f8239f2.
Original message
We don't have VP_ANY_EXTEND or VP_SIGN_EXTEND_INREG yet so I've
deviated a little from the non-VP lowering.
My goal was to fix the crashes that occurs on these test cases without this patch.
Reviewed By: fakepaper56
Differential Revision: https://reviews.llvm.org/D152854