From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konstantin Khlebnikov Subject: Re: [PATCH 4/4] bug: mark disabled BUG() as unreachable() code Date: Sat, 28 Apr 2012 09:10:18 +0400 Message-ID: <4F9B7BBA.7030504@openvz.org> References: <20120425112623.26927.43229.stgit@zurg> <20120425112636.26927.27124.stgit@zurg> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-lb0-f174.google.com ([209.85.217.174]:47532 "EHLO mail-lb0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750847Ab2D1FKY (ORCPT ); Sat, 28 Apr 2012 01:10:24 -0400 In-Reply-To: <20120425112636.26927.27124.stgit@zurg> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Linus Torvalds , "linux-kernel@vger.kernel.org" Cc: "linux-arch@vger.kernel.org" , Andrew Morton Konstantin Khlebnikov wrote: > This patch suppress some compiler warnings (if CONFIG_BUG=n) > "warning: control reaches end of non-void function" With this patch gcc throw out loop at the end of do_exit(): schedule(); BUG(); /* Avoid "noreturn function does return". */ for (;;) cpu_relax(); /* For when BUG is null */ Is this ok? Probably not, and we need here some BUG_NORETURN() which really never returns even if CONFIG_BUG=n. > > Plus now gcc can throw out some dead code. > bloat-o-meter: add/remove: 1/1 grow/shrink: 68/173 up/down: 1569/-5607 (-4038) > > Signed-off-by: Konstantin Khlebnikov > --- > include/asm-generic/bug.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h > index aadb6fc..0b08199 100644 > --- a/include/asm-generic/bug.h > +++ b/include/asm-generic/bug.h > @@ -108,7 +108,7 @@ extern void warn_slowpath_null(const char *file, const int line); > > #else /* !CONFIG_BUG */ > #ifndef HAVE_ARCH_BUG > -#define BUG() do {} while(0) > +#define BUG() unreachable() > #endif > > #ifndef HAVE_ARCH_BUG_ON >