From: "Uecker, Martin" <Martin.Uecker@med.uni-goettingen.de>
To: "torvalds@linux-foundation.org" <torvalds@linux-foundation.org>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: detecting integer constant expressions in macros
Date: Tue, 20 Mar 2018 22:13:35 +0000 [thread overview]
Message-ID: <1521584015.31174.3.camel@med.uni-goettingen.de> (raw)
Hi Linus,
here is an idea:
a test for integer constant expressions which returns an
integer constant expression itself which should be suitable
for passing to __builtin_choose_expr might be:
#define ICE_P(x) (sizeof(int) == sizeof(*(1 ? ((void*)((x) * 0l)) :
(int*)1)))
This also does not evaluate x itself on gcc although this is
not guaranteed by the standard. (And I haven't tried any older
gcc.)
Best,
Martin
next reply other threads:[~2018-03-20 22:19 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-20 22:13 Uecker, Martin [this message]
2018-03-20 23:07 ` detecting integer constant expressions in macros Uecker, Martin
2018-03-20 23:09 ` Linus Torvalds
2018-03-20 23:08 ` Linus Torvalds
2018-03-21 0:10 ` Uecker, Martin
2018-03-21 0:30 ` Linus Torvalds
2018-03-21 9:51 ` Uecker, Martin
2018-03-21 10:22 ` Uecker, Martin
2018-03-21 10:35 ` David Laight
2018-03-21 21:10 ` Rasmus Villemoes
2018-03-21 22:27 ` Linus Torvalds
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