Fix a tcb crash and a potential bug on mainline

Andrew MacLeod amacleod@redhat.com
Wed Oct 20 16:53:00 GMT 2004


On Wed, 2004-10-20 at 09:59, Steven Bosscher wrote: 
> On Wednesday 20 October 2004 15:41, Andrew MacLeod wrote:
> > Why doesnt cleanup_control_flow actually follow the flow from entry to
> > exit instead of FOR_EACH_BB?
> 
> I'm asking myself that each time I see FOR_{EACH,ALL}_BB.
> 
> >  Does it have to do something in blocks
> > that are unreachable?
> 
> No.
> 
> >  Or is it just an attempt to avoid using a visited
> > bitmap?
> 
> And a stack for backtracking.

yeah, I guess, but still, thats not so bad.  


> I've been thinking for some time now about implementing FOR_EACH_BB_DFS
> (and perhaps other visiting orders) using some iterator.  You think that
> would be a good idea?

Wasnt Dan mumbling something a while ago about an iterator to visit in
dominator order too?

I suspect there are uses for such things. I also suspect its done by
hand in more than a few places too.  I also thought we had something
once upon a time that followed the edges ike that, but I could be
mistaken.

I've never looked at all the FOR_*_BB loops to see how useful it would
be.

Andrew



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