cfg merge part 23 - simple loop analysis code

[Jan Hubicka]

> On Thu, Jun 20, 2002 at 05:11:31PM +0200, Jan Hubicka wrote:
> > > You're needlessly searching the insn stream twice.
> > 
> > This is already replaced by faster analysis.
> [...]
> > > Seems like you should perform a simple invariance test
> > > on VAL before searching.
> > 
> > Also killed by Zdenek.
> 
> Good to hear.
> 
> > The code is used by unrolling/peeling to do runtime preconditioning and
> > full peeling epsecially.
> > I am not quite sure whether we can do it for 3.2.  What is missing is
> > about 800 lines of code to duplicate loops, remove edges and update
> > dominance and 600 lines of the unroller itself.
> 
> Hum.  It's a quandry.  On the one hand, it sounds like your
> code isn't quite ready for 3.2.
Huh, just to mention that the code is on the branch, so it is written,
just not reviewed for mainline.