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Re: RFH: Impose code-movement restrictions and value assumption (for ASYNCHRONOUS/Coarrays)
On Sat, 16 Jul 2011, Richard Guenther wrote:
> > Did you really want to say this? ÂBecause I'm very sure we actually
> > loose very much in real-world performance if we wouldn't be using it
> > (or some alterntive that is specified somewhat cleaner).
> I meant to say if we are not using restrict but another more
> frontend-specific flag as suggested. Not if we drop restrict without
> replacing it with anything else.
I see. Well, whatever frontend specific flag we want to invent, it always
will be the case that the information conveyed by it somehow has to be
represented for the middle end, and that it must survive pointer-taking
and pointer-adjustment. It can survive these operations either by
1) being placed directly on the memory accesses right from the start in
2) creating a tracking device looking backward from mem accesses through
pointer-take/modify until we hit a so marked entity (probably a DECL)
3) modifying the type of such marked entity (which ripples down to the
mem access automatically then)
Currently we have a mix of (3) (to determine the speciality of some
pointers at all) and (2) (to determine which particular set of the
partition of all such special pointers a certain pointer belongs to). I
don't really see how this would change much in structure however we define
the frontend flags.