On Mon, Aug 4, 2025 at 1:08 PM Luc Grosheintz <luc.groshei...@gmail.com>
wrote:
> Hi Tomasz,
>
> Thank you for the review! Sorry about the missing parens, even after
> "Ctrl+F"ing each of the emails I can't find the requires clause (the
> two I found both need the parens).
>
I was mentioning this one, but it is possible that I am wrong on this one,
I haven't yet checked it, as I was planning to do it during full review.
template<array _Extents>
requires (__all_dynamic<_Extents>())
class _StaticExtents<_Extents>;
But regardless, I will make that change locally if it does work, so you do
not
need to update patch series for it.
>
> Do you think it's possible to merge this series before the other two
> outstanding patch series? There's some risk of collision; making changes
> to this patch series is much more time consuming than rebasing (and
> retesting the other two patch series).
>
This sounds very reasonable. I will prepare a stack of patches in your
suggested
order locally, and push them once they are approved. But it still make
>
> Thank you,
>
Thank you for your continued contributions.
> Luc
>
> On 8/4/25 12:43, Tomasz Kaminski wrote:
> > Hi,
> >
> > I this time I made a quick pass through all changes, before commenting on
> > first commits,
> > and they look solid to me, and I haven't noticed anything I would like to
> > change (except parentheses
> > around requires, but I will handle that locally). I will try to do a full
> > review during this week.
> >
> > Regards,
> > Tomasz
> >
> > On Sun, Aug 3, 2025 at 10:59 PM Luc Grosheintz <luc.groshei...@gmail.com
> >
> > wrote:
> >
> >> The combined effect of this sequence of change is:
> >>
> >> * a reduction in the number of template instantiations, by
> >> - avoiding needless dependency of IndexType,
> >> - special formulas for low-rank extents,
> >> - special formulas for (nearly) fully dynamic extents.
> >>
> >> * improved code quality, by
> >> - precomputing partial products of the static extents,
> >> - special cases for low-rank extents,
> >> - rewriting the condition E[i] == dynamic_extent in a more
> >> optimizer friendly manner.
> >> - effectively loop-unrolling extents::operator==.
> >>
> >> While simplistic micro-benchmarking shows the effectiveness of these
> >> changes, likely the stronger argument is presented in each commit:
> >> a) each change removes needless complexity,
> >> b) before/after examples of generated code show the effectiveness.
> >>
> >> Luc Grosheintz (8):
> >> libstdc++: Reduce template instantiations in <mdspan>.
> >> libstdc++: Precompute products of static extents.
> >> libstdc++: Improve low-rank layout_{left,right}::stride.
> >> libstdc++: Improve fully dynamic extents in mdspan.
> >> libstdc++: Improve nearly fully dynamic extents in mdspan.
> >> libstdc++: Reduce indirection in extents::extent.
> >> libstdc++: Improve extents::operator==.
> >> libstdc++: Replace numeric_limit with __int_traits in mdspan.
> >>
> >> libstdc++-v3/include/std/mdspan | 282 +++++++++++++-----
> >> .../mdspan/extents/class_mandates_neg.cc | 3 +
> >> 2 files changed, 208 insertions(+), 77 deletions(-)
> >>
> >> --
> >> 2.50.0
> >>
> >>
> >
>
>
