On Power9, we currently don't have pattern to select the following intrinsics:
llvm.ppc.vsx.stxvw4x.be
llvm.ppc.vsx.stxvd2x.be
The patterns already exist but are guarded by HasOnlySwappingMemOps, which is not set for Power9.
Moved patterns down to be with int_ppc_vsx_lxvw4x_be, int_ppc_vsx_lxvd2x_be which aren't guarded for Power9.