On 02/06/2017 08:33 AM, Richard Biener wrote:
ah, indeed vr0type is VR_ANTI_RANGE and yes we have the case
of a range with an anti-range "inside". This also covers [-1,1] v ~[0,0]
where you choose the much larger anti-range now. So at least we
want to have some idea about the sizes of the ranges (ideally we'd
choose the smaller though for most further propagations anti-ranges
often degenerate to varying...)
vr0 as an anti-singleton range like ~[0,0] is the only one likely of any
interest right now and that's always going to have a range that is all
but one value :-)
vr1 is the tricky case. We could do v1.max - vr1.min and if that
overflows or is some "large" value (say > 65536 just to throw out a
value), then we conclude creating the singleton anti-range like ~[0,0]
is more useful.
Jeff
