linux-kernel - [PATCH 05/10] minmax: simplify __clamp_once() by using is_const

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Message-Id: <20241203-is_constexpr-refactor-v1-5-4e4cbaecc216@wanadoo.fr>
Date: Tue, 03 Dec 2024 02:33:27 +0900
From: Vincent Mailhol via B4 Relay <devnull+mailhol.vincent.wanadoo.fr@...nel.org>
To: Linus Torvalds <torvalds@...ux-foundation.org>, 
 David Laight <David.Laight@...lab.com>, 
 Luc Van Oostenryck <luc.vanoostenryck@...il.com>, 
 Nathan Chancellor <nathan@...nel.org>, 
 Nick Desaulniers <ndesaulniers@...gle.com>, 
 Bill Wendling <morbo@...gle.com>, Justin Stitt <justinstitt@...gle.com>, 
 Yury Norov <yury.norov@...il.com>, 
 Rasmus Villemoes <linux@...musvillemoes.dk>, Kees Cook <kees@...nel.org>, 
 "Gustavo A. R. Silva" <gustavoars@...nel.org>, 
 Jani Nikula <jani.nikula@...ux.intel.com>, 
 Joonas Lahtinen <joonas.lahtinen@...ux.intel.com>, 
 Rodrigo Vivi <rodrigo.vivi@...el.com>, 
 Tvrtko Ursulin <tursulin@...ulin.net>, David Airlie <airlied@...il.com>, 
 Simona Vetter <simona@...ll.ch>, Suzuki K Poulose <suzuki.poulose@....com>, 
 Mike Leach <mike.leach@...aro.org>, James Clark <james.clark@...aro.org>, 
 Alexander Shishkin <alexander.shishkin@...ux.intel.com>, 
 Rikard Falkeborn <rikard.falkeborn@...il.com>, 
 Martin Uecker <Martin.Uecker@....uni-goettingen.de>
Cc: linux-sparse@...r.kernel.org, linux-kernel@...r.kernel.org, 
 llvm@...ts.linux.dev, linux-hardening@...r.kernel.org, 
 intel-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org, 
 coresight@...ts.linaro.org, linux-arm-kernel@...ts.infradead.org, 
 Vincent Mailhol <mailhol.vincent@...adoo.fr>
Subject: [PATCH 05/10] minmax: simplify __clamp_once() by using
 is_const_false()

From: Vincent Mailhol <mailhol.vincent@...adoo.fr>

In __clamp_once(),

  __builtin_choose_expr(__is_constexpr((lo) > (hi)), (lo) <= (hi), true)

is equivalent to:

  !is_const_false((lo) <= (hi))

Apply is_const_false() to simplify __clamp_once().

Signed-off-by: Vincent Mailhol <mailhol.vincent@...adoo.fr>
---
 include/linux/minmax.h | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h
index 98008dd92153db10c672155bca93201ffabee994..431bf76ac460a11a2e4af23acd90c0d26e99c862 100644
--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -111,8 +111,7 @@
 	__auto_type uval = (val);						\
 	__auto_type ulo = (lo);							\
 	__auto_type uhi = (hi);							\
-	static_assert(__builtin_choose_expr(__is_constexpr((lo) > (hi)), 	\
-			(lo) <= (hi), true),					\
+	static_assert(!is_const_false((lo) <= (hi)),				\
 		"clamp() low limit " #lo " greater than high limit " #hi);	\
 	BUILD_BUG_ON_MSG(!__types_ok3(val,lo,hi,uval,ulo,uhi),			\
 		"clamp("#val", "#lo", "#hi") signedness error");		\

-- 
2.45.2