Case where anti-dependency doesn't need pipeline stalling
You can eliminate anti-dependences (WAR dependences) with register renaming, so if you're doing renaming there will be no stalls from anti-dependences.  The other case is if you already know the write isn't going to interfere with the read (for example you know all the instructions with reads in them have already done their register reads).

Note that the traditional "5-stage" pipeline is doing the equivalent of register renaming using its bypass registers, so in that case you never need to stall.