[patch] for PRs 27639 and 26719

[Eric Botcazou]

> You cannot handle the types differently in scev_probably_wraps_p and in
> convert_affine_scev.

Could you elaborate?  Why is it not OK to be more conservative in both 
functions for subtypes?  In particular, I don't understand why returning true 
from scev_probably_wraps_p more often would be problematic.

/* Return false only when the induction variable BASE + STEP * I is
   known to not overflow: i.e. when the number of iterations is small
   enough with respect to the step and initial condition in order to
   keep the evolution confined in TYPEs bounds.  Return true when the
   iv is known to overflow or when the property is not computable.

-- 
Eric Botcazou