From: Jonathan Wakely <jwakely@redhat.com>
To: Patrick Palka <ppalka@redhat.com>
Cc: gcc-patches@gcc.gnu.org, libstdc++@gcc.gnu.org
Subject: Re: [PATCH 2/3] libstdc++: Simplify copy-pasted algorithms in <ranges>
Date: Thu, 1 Apr 2021 15:07:22 +0100 [thread overview]
Message-ID: <20210401140722.GS3008@redhat.com> (raw)
In-Reply-To: <20210329184915.3921422-2-ppalka@redhat.com>
On 29/03/21 14:49 -0400, Patrick Palka via Libstdc++ wrote:
>The <ranges> header currently copies some simple algorithms from
><bits/ranges_algo.h>, which was originally done in order to avoid a
>circular dependency with the header. This is no longer an issue since
>the latter header now includes <bits/ranges_util.h> instead of all of
><ranges>.
>
>This means we could now just include <bits/ranges_algo.h> and remove the
>copied algorithms, but that would double the size of <ranges>. And we
>can't use the corresponding STL-style algorithms here because they
>assume input iterators are copyable. So this patch instead simplifies
>these copied algorithms, removing their constraints and unused
>parameters, and keeps them around. In a subsequent patch we're going to
>copy ranges::find into <ranges> as well.
>
>libstdc++-v3/ChangeLog:
>
> * include/std/ranges (__detail::find_if): Simplify.
> (__detail::find_if_not): Likewise.
> (__detail::min): Remove.
> (__detail::mismatch): Simplify.
> (take_view::size): Use std::min instead of __detail::min.
I wonder if we want a <bits/ranges_algobase.h> which has this subset
of algos. That could be used from <ranges> and also from the real
algos in <bits/ranges_algo.h>. The ones in ranges_algobase.h wouldn't
need to have the constraints (because we know the caller is
constrained, or uses them correctly), but for that to work the unused
params would need to be re-added. We can consider that for GCC 12
though.
So OK for GCC 11.
next prev parent reply other threads:[~2021-04-01 14:07 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-29 18:49 [PATCH 1/3] libstdc++: Fix elements_view::operator* and operator[] [LWG 3502] Patrick Palka
2021-03-29 18:49 ` [PATCH 2/3] libstdc++: Simplify copy-pasted algorithms in <ranges> Patrick Palka
2021-03-29 18:53 ` Patrick Palka
2021-04-01 14:07 ` Jonathan Wakely [this message]
2021-03-29 18:49 ` [PATCH 3/3] libstdc++: Fix split_view::_OuterIter::operator++ [LWG 3505] Patrick Palka
2021-04-01 14:03 ` Jonathan Wakely
2021-04-01 14:00 ` [PATCH 1/3] libstdc++: Fix elements_view::operator* and operator[] [LWG 3502] Jonathan Wakely
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