[PATCH]: Fix places where we expect non-null loops in the loop array

[Diego Novillo]

Daniel Berlin wrote:

> Okay, so, uh, guys, what do you want me to do?
> Make things ignore null loops (which is what everything does now)?
> 
Sure.  Sounds like this is the easiest approach for now.  Also add some 
note in the loop structures to make sure other users are aware of this.


Diego.