There was a previous implementation with patterns that would
have matched e.g.
shl <v4i32> <i32>,
but this is not valid LLVM IR so they never were selected.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126998 91177308-0d34-0410-b5e6-96231b3b80d8