From: Linus Torvalds <torvalds@linuxfoundation.org>
To: Arnd Bergmann <arnd@kernel.org>
Cc: David Laight <David.Laight@aculab.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Matthew Wilcox <willy@infradead.org>,
Christoph Hellwig <hch@infradead.org>,
Andrew Morton <akpm@linux-foundation.org>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Dan Carpenter <dan.carpenter@linaro.org>,
"Jason A . Donenfeld" <Jason@zx2c4.com>,
"pedro.falcato@gmail.com" <pedro.falcato@gmail.com>,
Mateusz Guzik <mjguzik@gmail.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>
Subject: Re: [PATCH 4/7] minmax: Simplify signedness check
Date: Wed, 24 Jul 2024 13:02:50 -0700 [thread overview]
Message-ID: <CAHk-=wh_+muDANgpjC6_31QMh4OnKEOgbZiD_MymHxAHRZRyqg@mail.gmail.com> (raw)
In-Reply-To: <ef130c0a-b82f-472f-8c53-f7ef4c236c44@app.fastmail.com>
On Wed, 24 Jul 2024 at 09:49, Arnd Bergmann <arnd@kernel.org> wrote:
>
> I don't understand why this return '0' for unsigned types,
> shouldn't this be
>
> ((is_unsigned_type(typeof(x)) ? 1 : __if_constexpr(x, (x) + 0, -1)) >= 0)
Yes, that looks more logical.
Plus why do that "__if_constexpr(x, (x) + 0, -1)) >= 0)" when it would
appear to be more logical to move the comparison inside, ie
__if_constexpr(x, (x) >= 0, 0)
but I also don't see why that "+ 0" existed in the original. So
there's presumably something I'm missing.
I do get the feeling that the problem came from us being much too
clever with out min/max macros, and now this series is doubling down
instead of saying "it wasn't really worth it".
Linus
next prev parent reply other threads:[~2024-07-24 20:03 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-07-24 14:26 [PATCH 0/7] minmax: reduce compilation time David Laight
2024-07-24 14:28 ` [PATCH 1/7] minmax: Put all the clamp() definitions together David Laight
2024-07-24 14:29 ` [PATCH 2/7] minmax: Use _Static_assert() instead of static_assert() David Laight
2024-07-24 14:29 ` [PATCH 3/7] compiler.h: Add __if_constexpr(expr, if_const, if_not_const) David Laight
2024-07-24 17:32 ` Arnd Bergmann
2024-07-25 9:12 ` David Laight
2024-07-24 19:48 ` Linus Torvalds
2024-07-25 8:45 ` David Laight
2024-07-24 14:30 ` [PATCH 4/7] minmax: Simplify signedness check David Laight
2024-07-24 16:48 ` Arnd Bergmann
2024-07-24 20:02 ` Linus Torvalds [this message]
2024-07-25 9:00 ` David Laight
2024-07-25 17:02 ` Linus Torvalds
2024-07-26 9:43 ` Lorenzo Stoakes
2024-07-26 12:57 ` David Laight
2024-07-26 13:27 ` Lorenzo Stoakes
2024-07-25 13:24 ` kernel test robot
2024-07-25 16:39 ` David Laight
2024-07-24 14:31 ` [PATCH 5/7] minmax: Factor out the zero-extension logic from umin/umax David Laight
2024-07-24 14:32 ` [PATCH 6/7] minmax: Optimise _Static_assert() check in clamp() David Laight
2024-07-24 14:33 ` [PATCH 7/7] minmax: minmax: Add __types_ok3() and optimise defines with 3 arguments David Laight
2024-07-24 17:03 ` Arnd Bergmann
2024-07-25 9:07 ` David Laight
2024-07-24 19:34 ` [PATCH 0/7] minmax: reduce compilation time Lorenzo Stoakes
2024-07-24 19:52 ` Linus Torvalds
2024-07-26 18:12 ` Lorenzo Stoakes
2024-07-26 18:24 ` Linus Torvalds
2024-07-26 18:56 ` Lorenzo Stoakes
2024-07-26 19:21 ` Lorenzo Stoakes
2024-07-26 21:36 ` Linus Torvalds
2024-07-26 21:46 ` Jens Axboe
2024-07-26 22:48 ` Linus Torvalds
2024-07-27 15:30 ` Jens Axboe
2024-07-27 15:38 ` Jens Axboe
2024-07-27 16:31 ` Lorenzo Stoakes
2024-07-27 16:36 ` Jens Axboe
2024-07-27 16:41 ` Lorenzo Stoakes
2024-07-27 16:52 ` Jens Axboe
2024-07-27 16:56 ` Lorenzo Stoakes
2024-07-28 11:32 ` David Laight
2024-07-27 4:13 ` Linus Torvalds
2024-07-27 4:14 ` Linus Torvalds
2024-07-27 8:08 ` David Laight
2024-07-27 18:58 ` Lorenzo Stoakes
2024-07-27 19:21 ` Linus Torvalds
2024-07-28 11:17 ` David Laight
2024-07-28 13:07 ` Lorenzo Stoakes
2024-07-27 17:33 ` Matthew Wilcox
2024-07-27 18:16 ` Linus Torvalds
2024-07-27 8:07 ` Lorenzo Stoakes
2024-07-27 16:26 ` Linus Torvalds
2024-07-27 18:44 ` Lorenzo Stoakes
2024-07-30 4:10 ` Linus Torvalds
2024-07-30 10:36 ` Arnd Bergmann
2024-07-28 17:57 ` Geert Uytterhoeven
2024-07-28 18:43 ` Lorenzo Stoakes
2024-07-26 21:32 ` David Laight
2024-07-26 21:38 ` Linus Torvalds
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