Date: Sun, 30 Aug 2015 15:36:27 +1000 (EST) From: Bruce Evans <brde@optusnet.com.au> To: Joerg Sonnenberger <joerg@britannica.bec.de> Cc: Bruce Evans <brde@optusnet.com.au>, Xin LI <delphij@freebsd.org>, svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r287217 - head/usr.sbin/syslogd Message-ID: <20150830151625.K1159@besplex.bde.org> In-Reply-To: <20150828143847.GA24222@britannica.bec.de> References: <201508271811.t7RIB0xl077002@repo.freebsd.org> <20150828215109.G1227@besplex.bde.org> <20150828143847.GA24222@britannica.bec.de>
next in thread | previous in thread | raw e-mail | index | archive | help
On Fri, 28 Aug 2015, Joerg Sonnenberger wrote: > On Fri, Aug 28, 2015 at 10:17:56PM +1000, Bruce Evans wrote: >>> -static void die(int); >>> +static void die(int) __dead2; >> >> Since the function is static, it is very easy for the compiler to see >> that it doesn't return. > > But the compiler can't tell if it is the *intention* that the function > never returns. The warning behavior exists because that can easily > change with macros etc. The compiler should trust the programmer to write correct functions. >> Even gcc-4.2.1 does this by default, since >> -O implies -funit-at-a-time for gcc-4.2.1. For clang, there is no way >> to prevent this (except possibly -O0) since, since -fno-unit-at-a-time >> is broken in clang. > > It is not broken. It is loadly ignored as unsupported. The very > existance of the option in GCC has always been a concession to broken > and badly written code, including of course GCC's own CRT. Unsupported == incompatible == broken. My use of this option can probably be reduced to -fno-toplevel-reorder, but that is even more broken in clang (it and -ftoplevel-reorder are "unknown arguments", while -fno-unit-at-a-time is an "unsupported optimization", and -funit-at-a-time works). Bruce
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20150830151625.K1159>