Re: [lno] tree-ssa merge

[Pop Sebastian <pop at gauvain dot u-strasbg dot fr>]

On Mon, Jan 26, 2004 at 03:09:26PM +0200, Dorit Naishlos wrote:
> 
> 
> 
> 
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> > Yes, I'm working on making the analyzer work again correctly.  The
> > changes brought in code that is equivalent of the loop header copy:
> > instead of having the exit condition of a loop at the top of the loop,
> > ....
> > ....
> > Based on the fact that the loop count is computed using the exit
> > expression, the nb_iterations is thus sometimes one iteration less
> > than the true number of iterations.  In fact, at the moment, the
> > nb_iterations is the number of times the exit condition has to be
> > evaluated at runtime before exiting the loop.  I'm working on a fix.
> 
> Thanks for the detailed explanation Sebastian - I have also fixed the
> loop-bound transformation in the vectorizer accordingly. 

My first message was not clear.  

The value that is stored in nb_iterations is currently broken: it
should be the number of iterations in the loop, and not the number of
evaluations of the exit condition.  One of the patches I'm working on
fixes this.  You can use a temporary patch for this, but then you'll
maybe have to revert it.