[PPC] Previously when casting generic loads to LXV2DX/ST instructions we
would leave the original load return type in place allowing for an
assertion failure when we merge two equivalent LXV2DX nodes with
different types.
This fixes PR27350.
Reviewers: nemanjai
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D19133
llvm-svn: 266438
