There is no such op. If you add a continue block, you'll notice that lineseq has three arguments/statements instead of just two. If you want to run something at the end of every loop, alter the optree to wire your op in.
Heh. Not a bad idea if that is the only way to do it. Unfortunately I lack experience doing evil things to perl. Any idea on where I should be looking to do so? I understand perly.y has the grammar, or what there is of it, but I was a little confused how I could make it add an op.