Hi Jeff,
> So if we're going from 0->2 ULPs in some cases, do we want to guard it
> with one of the various options, if so, which? Giuliano's follow-up
> will still have the potential for 2ULPs.
The ULP difference is not important since the individual math functions
already have ULP of 3 or higher. Changing ULP error for some or all inputs
(like we did with the rewritten math functions) is not considered an issue as
long as worst-case ULP error doesn't increase.
The question is more like whether errno and trapping/exception behaviour
is identical - I guess it is not so I would expect this to be fastmath only.
Which particular flag one uses is a detail given there isn't a clear definition
for most of them.
Wilco
