On Tuesday 21 March 2006 18:01, Jeffrey A Law wrote: > On Tue, 2006-03-21 at 17:41 +0100, Duncan Sands wrote: > > > Should it be? I was surprised to see that all ranges are initialised > > to VR_VARYING in the vrp pass, since many types have natural ranges > > associated with them, for example [0, 255] for the above unsigned char; > > starting off with this natural range is, well, natural, and surely > > simplifies a bunch of code, by making things more uniform, eg: no need > > to special case unsigned values, type conversions, ... > Depends on who you talk to -- we certainly have a problem in that we > have two ways to represent the same thing and the optimizer treats > the two representations differently. > > In a world where we could handle VR_VARYING without pessimizing so > much, then I don't think either representation would be clearly > better than the other.
Is memory use a problem here? VR_VARYING has the advantage of using a bit less memory. On the other hand, I guess you could introduce the convention that VR_RANGE with null min/max means to use TYPE_MIN/ TYPE_MAX, or something along those lines. Ciao, D.
