From: Vincent Lefevre <vincent+gcc@vinc17.org>
To: Daniel Santos <daniel.santos@pobox.com>
Cc: Joseph Myers <joseph@codesourcery.com>,
Jonathan Wakely <jwakely.gcc@gmail.com>,
Allan Sandfeld Jensen <linux@carewolf.com>,
"gcc@gcc.gnu.org" <gcc@gcc.gnu.org>,
Richard Henderson <rth@redhat.com>,
Florian Weimer <fweimer@redhat.com>
Subject: Re: [RFC] GCC 8 Project proposal: Extensions supporting C Metaprogramming, pseudo-templates
Date: Mon, 15 May 2017 11:31:00 -0000 [thread overview]
Message-ID: <20170515113137.GB32647@cventin.lip.ens-lyon.fr> (raw)
In-Reply-To: <57c2e272-dc55-62a5-5984-382867468723@pobox.com>
On 2017-05-12 15:59:44 -0500, Daniel Santos wrote:
> [...] But from a conceptual standpoint, I believe the term
> "constant-expression" would be incorrect because the C standard
> defines this constraint: (6.6.3 of C11) "Constant expressions shall
> not contain assignment, increment, decrement, function-call, or
> comma operators, except when they are contained within a
> subexpression that is not evaluated." I definitely do need to study
> the C specs more carefully to make sure I fully understand how this
> is used and how it's changed over different revisions of the spec.
GCC already regards some function calls are acceptable in
constant expressions, when builtins are used, e.g. fabs (2.0),
contrary to Clang. The builtin is even used when <math.h> is
not included (note that Clang has the same behavior here). So,
there may be several issues. I've reported:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80756
--
Vincent Lefèvre <vincent@vinc17.net> - Web: <https://www.vinc17.net/>
100% accessible validated (X)HTML - Blog: <https://www.vinc17.net/blog/>
Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)
next prev parent reply other threads:[~2017-05-15 11:31 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-08 23:32 Daniel Santos
2017-05-09 9:36 ` Florian Weimer
2017-05-10 8:46 ` Daniel Santos
2017-05-09 13:29 ` Allan Sandfeld Jensen
2017-05-10 9:13 ` Daniel Santos
2017-05-10 9:24 ` Jonathan Wakely
2017-05-10 22:09 ` Daniel Santos
2017-05-11 10:12 ` Jonathan Wakely
2017-05-11 10:44 ` Marek Polacek
2017-05-11 14:35 ` Joseph Myers
2017-05-12 20:54 ` Daniel Santos
2017-05-12 21:03 ` Joseph Myers
2017-05-15 11:31 ` Vincent Lefevre [this message]
2017-05-12 15:49 ` Martin Sebor
2017-05-12 21:11 ` Daniel Santos
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