From: Gonzalo Brito Gadeschi <gonzalo.gadeschi@gmail.com>
To: gcc-patches@gcc.gnu.org, libstdc++@gcc.gnu.org, pilarlatiesa@gmail.com
Subject: Re: [PATCH v2] libstdc++: PSTL dispatch for C++20 range random access iterators [PR110512]
Date: Sat, 11 Nov 2023 10:11:47 -0800 [thread overview]
Message-ID: <CAPju=KOj+fy4QeFX2e6X_vq1sTLmPs5Ext6x=JMhbhzb_ZWEFQ@mail.gmail.com> (raw)
In-Reply-To: <CAPju=KM4G1tw0SbGLc5h_dumXhRXyfYW=SdeX77C70UeEv4dcQ@mail.gmail.com>
[-- Attachment #1: Type: text/plain, Size: 2313 bytes --]
@Pilar, this is the patch. Let me know if you need any help or have
questions. Thank you !
On Mon 3. Jul 2023 at 09:02, Gonzalo Brito Gadeschi <
gonzalo.gadeschi@gmail.com> wrote:
> libstdc++: Recognize C++ random access iterators as random access in PSTL
> [PR110432]
>
> The check for random access iterators in the PSTL only checks whether the
> iterator inherits from the random_access_iterator_tag, failing to recognize
> random access iterators originating in C++20 ranges and views.
>
> This patch extends the check to also recognize types that model the C++20
> random_access_iterator concept as providing random access.
>
> This is allowed by C++23's P2408, which is safe to backport to C++20,
> because
> any application that would break already exhibits undefined
> behavior due to precondition violation.
>
> libstdc++-v3/ChangeLog:
> PR libstdc++/110512
> * include/pstl/execution_impl.h Recognize C++20 random access iterators as
> random access.
>
> Bootstrapping and testing
> * Tested with x86_64-pc-linux-gnu.
>
> ---
> libstdc++-v3/include/pstl/execution_impl.h | 10 +++++++++-
> 1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/libstdc++-v3/include/pstl/execution_impl.h
> b/libstdc++-v3/include/pstl/execution_impl.h
> index 64f6cc4357a..c17da29141e 100644
> --- a/libstdc++-v3/include/pstl/execution_impl.h
> +++ b/libstdc++-v3/include/pstl/execution_impl.h
> @@ -22,7 +22,15 @@ namespace __internal
>
> template <typename _IteratorTag, typename... _IteratorTypes>
> using __are_iterators_of = std::conjunction<
> - std::is_base_of<_IteratorTag, typename
> std::iterator_traits<std::decay_t<_IteratorTypes>>::iterator_category>...>;
> +#if __cplusplus >= 202002L
> + std::disjunction<
> + std::is_base_of<_IteratorTag, typename
> std::iterator_traits<std::decay_t<_IteratorTypes>>::iterator_category>,
> + std::integral_constant<bool,
> std::random_access_iterator<_IteratorTypes>>
> + >...
> +#else // __cplusplus
> + std::is_base_of<_IteratorTag, typename
> std::iterator_traits<std::decay_t<_IteratorTypes>>::iterator_category>...
> +#endif // __cplusplus
> +>;
>
> template <typename... _IteratorTypes>
> using __are_random_access_iterators =
> __are_iterators_of<std::random_access_iterator_tag, _IteratorTypes...>;
>
> --
> 2.17.1
>
prev parent reply other threads:[~2023-11-11 18:12 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-03 16:02 Gonzalo Brito Gadeschi
2023-11-11 18:11 ` Gonzalo Brito Gadeschi [this message]
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