https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85726
Hans-Peter Nilsson <hp at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |NEW
Assignee|hp at gcc dot gnu.org |unassigned at gcc dot
gnu.org
--- Comment #5 from Hans-Peter Nilsson <hp at gcc dot gnu.org> ---
(In reply to Jakub Jelinek from comment #4)
> Regressed with r218211 aka PR15346. Hans-Peter, are you still working on
> this or where the thread died?
Oops, no I'm not actively working on this; de-assigning now.
(I did mean to pick up the thread, sooner or later. For example, I checked
that my match.pd patch for div (without the mult parts) had only benevolent
effects AFAIU for x86_64, but got distracted before reporting on that. And,
changes were requested in the this-is-not-a-review-replies (i.e. a
side-condition of mod also matching or similar) that I had to figure out how to
implement; maybe that's what you did.)
So...
> Do we want to do just something directed at this case, i.e. don't combine
> two divisions if the lhs of the first one is also used in a modulo with the
> same last operand as the second division and both are e.g. in the same bb?
I don't know. If your patch handles the test-case, as I guess it does from a
quick look, then I'm happy. The original code was manually unrolled loops and
I *think* all the expressions were in the same bb. Thanks!
