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From: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
To: Linus Torvalds <torvalds@linux-foundation.org>,
	Yury Norov <yury.norov@gmail.com>,
	Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Cc: linux-kernel@vger.kernel.org, linux-sparse@vger.kernel.org,
	Rikard Falkeborn <rikard.falkeborn@gmail.com>,
	Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Subject: [PATCH v4 2/2] linux/bits.h: simplify GENMASK_INPUT_CHECK()
Date: Thu, 14 Nov 2024 02:18:33 +0900	[thread overview]
Message-ID: <20241113172939.747686-6-mailhol.vincent@wanadoo.fr> (raw)
In-Reply-To: <20241113172939.747686-4-mailhol.vincent@wanadoo.fr>

In GENMASK_INPUT_CHECK(),

  __builtin_choose_expr(__is_constexpr((l) > (h)), (l) > (h), 0)

is the exact expansion of:

  const_true((l) > (h))

Apply const_true() to simplify GENMASK_INPUT_CHECK().

Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
---
This change passes the unit tests from CONFIG_BITS_TEST, including the
extra negative tests provided under #ifdef TEST_GENMASK_FAILURES [1].

[1] commit 6d511020e13d ("lib/test_bits.c: add tests of GENMASK")
Link: https://git.kernel.org/torvalds/c/6d511020e13d
---
 include/linux/bits.h | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/include/linux/bits.h b/include/linux/bits.h
index 60044b608817..61a75d3f294b 100644
--- a/include/linux/bits.h
+++ b/include/linux/bits.h
@@ -20,9 +20,8 @@
  */
 #if !defined(__ASSEMBLY__)
 #include <linux/build_bug.h>
-#define GENMASK_INPUT_CHECK(h, l) \
-	(BUILD_BUG_ON_ZERO(__builtin_choose_expr( \
-		__is_constexpr((l) > (h)), (l) > (h), 0)))
+#include <linux/compiler.h>
+#define GENMASK_INPUT_CHECK(h, l) BUILD_BUG_ON_ZERO(const_true((l) > (h)))
 #else
 /*
  * BUILD_BUG_ON_ZERO is not available in h files included from asm files,
-- 
2.45.2


  parent reply	other threads:[~2024-11-13 17:30 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-11-13 17:18 [PATCH v4 0/2] add const_true() to simplify GENMASK_INPUT_CHECK() Vincent Mailhol
2024-11-13 17:18 ` [PATCH v4 1/2] compiler.h: add const_true() Vincent Mailhol
2024-11-13 18:53   ` Yury Norov
2024-12-30 18:32     ` Yury Norov
2024-12-31  4:58       ` Vincent Mailhol
2024-11-17 17:42   ` David Laight
2024-11-17 18:00     ` Linus Torvalds
2024-11-17 19:02       ` Linus Torvalds
2024-11-17 19:05       ` David Laight
2024-11-17 19:09         ` Linus Torvalds
2024-11-17 19:23           ` David Laight
2024-11-17 20:12             ` Linus Torvalds
2024-11-17 22:38               ` David Laight
2024-11-17 22:58                 ` Linus Torvalds
2024-11-18  3:22                   ` Vincent Mailhol
2024-11-18  9:27                     ` David Laight
2024-11-18 17:09                     ` Linus Torvalds
2024-11-13 17:18 ` Vincent Mailhol [this message]
2024-11-17 17:24   ` [PATCH v4 2/2] linux/bits.h: simplify GENMASK_INPUT_CHECK() David Laight
2024-11-17 19:45     ` David Laight
2024-11-18  1:14       ` Vincent Mailhol
2024-11-18  1:12     ` Vincent Mailhol

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