Handle canonical form of e.g.
vector_shuffle v1, v1, <0, 4, 1, 5, 2, 6, 3, 7>

This is turned into
vector_shuffle v1, <undef>, <0, 0, 1, 1, 2, 2, 3, 3>
by dag combiner.

It would match a {p}unpckl on x86.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@27437 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed