_nonnegval() needs to be smarter - buildv.sac

Bugzilla Link	912
Created on	Feb 15, 2012 22:06
Resolution	FIXED
Resolved on	Feb 15, 2012 22:47
Version	svn
OS	Linux
Architecture	PC

Extended Description

Another cause of the APEX buildv.sac benchmark AWLF failure is this:
XX = _add_SxS_( 
        currentshape, iv);
XX', p = _non_neg_val_S_(  XX);
XX has an AVIS_MIN, but it is not constant: 
 currentshape is the running result shape, which is growing by
 catenation. So, it has AVIS_MIN of zero, which is good.
 iv is the WL index vector, and it has an AVIS_MIN of zero,
which is also good.
Normally, the guard would be removed if AVIS_MIN(XX)<=0.
But, that value is not constant, so the guard is not removed, at present.
However, we CAN remove the guard, with this observation:
Assume we are looking for a constant AVIS_MIN(XX).
If M=AVIS_MIN(XX) is not constant, look at AVIS_MIN(M)
to see if it's constant. Iterate this until we no longer
have an AVIS_MIN or until we hit a constant.