635ab515d5
If we're interleaving 2 constant splats, for instance `<vscale x 8 x i32> <splat of 666>` and `<vscale x 8 x i32> <splat of 777>`, we can create a larger splat `<vscale x 8 x i64> <splat of ((777 << 32) | 666)>` first before casting it back into `<vscale x 16 x i32>`.