Richard Guenther wrote:
> It's definitely safer. Still we have to carefully modify existing
> code to deal with the new tree codes as most of it carelessly
> transitiones old codes to new trees. For example re-associating
> (a +/nv b) + c to a +/nv (b + c) is wrong.
Yes, of course we have to take care when processing the new codes, but the
wonderful thing that I was pointing out is that none of the current
fold/simplify code will attempt to reassociate the new codes at first, until
it's been explicitly taught about them, whereas if we had used a flag it would
plough straight ahead under the misapprehension that it understood the
semantics of the tree code, that's all.
Anyway, your plan gets a big thumbs-up from me. The noobs will be endlessly
glad when signed ints start overflowing in the way they'd hoped, and the
fortran-wielding-heavy-duty-massive-array-number-crunching-academic types can
use a commandline option to make sure they still get their "loop optimiser
assumes your index won't overflow so loop must terminate" optimisations, won't
they?
cheers,
DaveK
