Remove unsightly empty expression
Remove unsightly empty expression

For the `frag` intrinsic.

cucapra/braid,cucapra/braid,guoyiteng/braid,guoyiteng/braid,guoyiteng/braid,cucapra/braid,guoyiteng/braid,guoyiteng/braid,cucapra/braid,guoyiteng/braid,cucapra/braid,cucapra/braid