From: Linus Torvalds <torvalds@linux-foundation.org>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: paulmck@kernel.org, linux-toolchains@vger.kernel.org,
peterz@infradead.org, rostedt@goodmis.org,
gregkh@linuxfoundation.org, keescook@chromium.org
Subject: Re: A few proposals from the C standards committee
Date: Tue, 23 Jan 2024 12:24:44 -0800 [thread overview]
Message-ID: <CAHk-=wid0xiN8a0=ixi3CyyZstcVnUqPXAMjethOxvXw1LjSuQ@mail.gmail.com> (raw)
In-Reply-To: <57324f9b-c851-4120-82b6-dbbf21cb2720@zytor.com>
On Tue, 23 Jan 2024 at 12:19, H. Peter Anvin <hpa@zytor.com> wrote:
>
> > n3203 Strict order of expression evaluation
> > I do like it. The 1980s were over a long time ago.
>
> The question is: is this going to wreck havoc with performance. The C++
> reference implies it won't, though.
Well, they also had numbers from an actual implementation showing that
it didn't (ie "win some, lose some").
The "ordering is undefined" is, I think, almost entirely an effect of
"compilers weren't that smart, and implementations differed".
So I'd love for sequence points to go away. They are one of the more
subtle parts of C, and I do not believe that they have any real
advantage any more.
(And by "go away" I obviously mean "everything is a sequence point",
not "nothing is a sequence point" - so they'd go away as a concept,
because they'd become a non-issue).
Linus
next prev parent reply other threads:[~2024-01-23 20:25 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-23 16:46 A few proposals from the C standards committee Paul E. McKenney
2024-01-23 18:58 ` Linus Torvalds
2024-01-23 20:00 ` Paul E. McKenney
2024-01-23 20:20 ` Linus Torvalds
2024-01-23 20:35 ` Jakub Jelinek
2024-01-23 20:43 ` Linus Torvalds
2024-01-23 20:46 ` H. Peter Anvin
2024-01-24 13:46 ` Paul E. McKenney
2024-01-25 13:00 ` Paul E. McKenney
2024-01-24 13:16 ` Paul E. McKenney
2024-01-23 20:44 ` H. Peter Anvin
2024-01-24 12:52 ` Paul E. McKenney
2024-01-23 20:39 ` Linus Torvalds
2024-01-23 22:35 ` Martin Uecker
2024-01-23 20:16 ` H. Peter Anvin
2024-01-23 20:24 ` Linus Torvalds [this message]
2024-01-24 14:58 ` Paul E. McKenney
2024-01-25 12:52 ` Paul E. McKenney
2024-01-23 22:39 ` Kees Cook
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