On Mon, 13 Mar 2023, Aldy Hernandez wrote:
>
>
> On 3/10/23 11:29, Jakub Jelinek wrote:
> > On Fri, Mar 10, 2023 at 08:53:37AM +0000, Richard Biener wrote:
> >> Meh - I wonder if we can avoid all this by making float_widen_lhs_range
> >> friend of frange and simply access m_min/m_max directly and use the
> >> copy-CTOR to copy bounds and nan state ... after all verify_range
> >> will likely fail after you restore flag_finite_math_only ...
> >
> > I'll defer such changes to Aldy.
> >
> > As for verification, I think verify_range will not fail on it, it mainly
> > checks whether it is normalized (e.g. if minimum is frange_val_min and
> > maximum is frange_val_max and NaNs are possible with both signs (if NaNs
> > are supported) then it is VR_VARYING etc.). It doesn't check if the actual
> > VR_RANGE bounds are smaller or larger than the VR_VARYING bounds, there is
> > just equality check.
> > Of course, behavior of wider than varying ranges is still unexpected in
> > many ways, say the union_ of such a range and VR_VARYING will ICE etc.
> >
> > Now, I guess another possibility for the reverse ops over these wider ranges
> > would be avoid calling fold_range in the reverse ops, but call rv_fold
> > directly or have fold_range variant which would instead of the op1, op2
> > argument have 2 triplets, op1, op1lb, op1ub, op2, op2lb, op2ub, and it
> > would use those const REAL_VALUE_TYPE &op??b in preference to
> > op?.{lower,upper}_bound () or perhaps normal fold_range be implemented
> > in terms of this extended fold_range. Then we wouldn't need to bother with
> > these non-standard franges...
> >
> >> But OK for the moment.
> >
> > Thanks, committed.
>
> I'm not a big fan of constructing ranges that break all our internal
> consistency checks. I'd also prefer to add another constructor (or add a flag
> to the current constructor) instead of making range-op-float routines friends.
> We also have bits in the vrange (or frange) that we could use for other
> semantics, especially since frange_storage can be streamlined when stored in
> GC/etc.
>
> I'm on PTO this week. Could we revisit this next week? And if worse comes to
> worse, leave it as is, and fix it properly next release?
Yes, sure - I just noticed that we're forced to use high-level API for
something that's quite low-level and should be internal (a range
"breaking" internal consistency checks).
Richard.
