i seem to have hit a problem with my new conflict finder.

[Andrew MacLeod]

On Fri, 2007-08-17 at 12:01 -0400, Kenneth Zadeck wrote:

> > In any case IRA can not use UREC because UREC is needed before IRA
> > calculates reg class info and the reg class info is needed for
> > calculation of UREC.  If you manage to use LIVE instead of UREC, it
> > would permit to use LIVE also in IRA instead of LR.  But I can not say
> > can we use LIVE instead of UREC because I don't know the
> > df-infrastructure well yet.
> >
> we should talk.  I am avail today.  i am leaving on vacation tomorrow
> for a week.
> 
> Even if this patch does not get in this round, you should consider it as
> a starting point for building the interference graph for ira.  
> 
> it does not use urec and a big part of the patch is just getting rid of
> urec,  It does a backwards scan using the live at bottom set as the
> starting point for the scan.
> This is the most accurate you can get so there really is no reason not
> to use it since it is also no more expensive than any weaker technique. 

It is the standard way of doing things. Out-Of-SSA has always used live
range info from the bottom up for its conflict graph. I'm marginally
suprised it is calculated any other way...

Andrew