From: "Arnd Bergmann" <arnd@kernel.org>
To: "David Laight" <David.Laight@aculab.com>,
"'linux-kernel@vger.kernel.org'" <linux-kernel@vger.kernel.org>,
"Linus Torvalds" <torvalds@linuxfoundation.org>
Cc: "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 3/7] compiler.h: Add __if_constexpr(expr, if_const, if_not_const)
Date: Wed, 24 Jul 2024 19:32:14 +0200 [thread overview]
Message-ID: <24be8665-4717-4ee2-8a81-80fed5181736@app.fastmail.com> (raw)
In-Reply-To: <9751d18defea406fa698630637d8e7db@AcuMS.aculab.com>
On Wed, Jul 24, 2024, at 16:29, David Laight wrote:
> +#define __if_constexpr(expr, if_const, if_not_const) \
> + _Generic(0 ? ((void *)((long)(expr) * 0l)) : (char *)0, \
> + char *: (if_const), \
> + void *: (if_not_const))
> +
> -#define __is_constexpr(x) \
> - (sizeof(int) == sizeof(*(8 ? ((void *)((long)(x) * 0l)) : (int *)8)))
> +#define __is_constexpr(expr) __if_constexpr((expr), 1, 0)
I don't immediately see anything wrong with this, but I'm
still scared of any change to it, especially if this is
meant to go straight into mainline.
Would it be possible to do patch 4/7 without the new
__if_constexpr() and instead still using __builtin_choose_expr()?
Arnd
next prev parent reply other threads:[~2024-07-24 17:33 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 [this message]
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
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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