public inbox for libstdc++@gcc.gnu.org
 help / color / mirror / Atom feed
From: Jonathan Wakely <jwakely@redhat.com>
To: libstdc++@gcc.gnu.org, gcc-patches@gcc.gnu.org
Subject: [committed 1/3] libstdc++: Fix std::span constraint for sizeof(size_t) < sizeof(int) [PR108221]
Date: Tue, 10 Jan 2023 11:46:55 +0000	[thread overview]
Message-ID: <20230110114657.636853-1-jwakely@redhat.com> (raw)

Tested x86_64-linux. Pushed to trunk.

-- >8 --

The default constructor has a constraint that is always false if
arithmetic on size_t values promotes to int. Rewrite the constraint
exactly as written in the standard, which works correctly.

libstdc++-v3/ChangeLog:

	PR libstdc++/108221
	* include/std/span (span::span()): Un-simplify constraint to
	work for size_t of lesser rank than int.
---
 libstdc++-v3/include/std/span | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libstdc++-v3/include/std/span b/libstdc++-v3/include/std/span
index 251fed91abf..b336332b190 100644
--- a/libstdc++-v3/include/std/span
+++ b/libstdc++-v3/include/std/span
@@ -145,7 +145,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
       constexpr
       span() noexcept
-      requires ((_Extent + 1u) <= 1u)
+      requires (_Extent == dynamic_extent || _Extent == 0)
       : _M_ptr(nullptr), _M_extent(0)
       { }
 
-- 
2.39.0


             reply	other threads:[~2023-01-10 11:47 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-10 11:46 Jonathan Wakely [this message]
2023-01-10 12:25 ` Jakub Jelinek
2023-01-10 13:03   ` Jonathan Wakely

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20230110114657.636853-1-jwakely@redhat.com \
    --to=jwakely@redhat.com \
    --cc=gcc-patches@gcc.gnu.org \
    --cc=libstdc++@gcc.gnu.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).