getSplatIndex assumes that the first element of the mask contains the splat index
which is not always true if the mask contains undefs. Modified it to return
the first non undef value.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96621 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed