[X86][SSE] Add v8i16 shift test for 2 shift values that doesn't match basic blend

We have special case support for 2 shift values for basic blends, but irregular shift patterns end up using the generic lowering, despite shuffle lowering being good enough to handle more complex blends.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@336112 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed