On Wed, May 17, 2023 at 01:55:00PM +0200, Frederik Harwath wrote:
> Thanks for the explanation. But actually doing this would require a
> complete rewrite which would almost certainly imply that mainline GCC
> would not support the loop transformations for a long time.
I don't think it needs complete rewrite, the change to use
OMP_UNROLL/OMP_TILE should actually simplify stuff when you already have
some other extra construct to handle the clauses if it isn't nested into
something else, so I wouldn't expect it needs more than 2-3 hours of work.
It is true that doing the transformation on trees rather than high gimple
is something different, but again it doesn't require everything to be
rewritten and we have code to do code copying both on trees and high and low
gimple in tree-inline.cc, so the unrolling can just use different APIs
to perform it.
I'd still prefer to do it like that, I think it will pay back in
maintainance costs.
If you don't get to this within say 2 weeks, I'll try to do the conversion
myself.
Jakub
