Re: [PATCH] Fix PR tree-optimization/17724 (take 2)

[Zdenek Dvorak <rakdver at atrey dot karlin dot mff dot cuni dot cz>]

Hello,

> On Sat, Oct 09, 2004 at 11:00:00AM +0200, Zdenek Dvorak wrote:
> > this does not seem to be the right fix to me:
> > 
> > 1) Change to delete_unreachable_blocks is not necessary.  As long as
> >    dominators are set correctly before delete_unreachable_blocks,
> >    they are also set correctly after it (since removal of unreachable
> >    blocks cannot affect any path from entry to basic block bb, and
> >    immediate dominator is determined from exactly these paths).
> 
> Are you sure that in all other cases where some basic blocks become
> unreachable code that removes the edge ensures that dominators are freed
> or recomputed for all basic blocks where idom(bb) could change?

not completely, of course.  Verify_dominators that is able to catch
such problems is run on several places, so I am fairly sure we update
dominators correctly most of the time, but of course there may be
some more buggy places.

Zdenek