AMDGPU: Turn int pack pattern into build_vector

build_vector is a more useful canonical form when
pattern matching packed operations, so turn shift
into high element into a build_vector.

Should show no change for now.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@312282 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed