From mboxrd@z Thu Jan 1 00:00:00 1970 From: Russell King - ARM Linux Subject: Re: [PATCH] Turn off -Wmaybe-uninitialized when building with -Os Date: Fri, 15 Mar 2013 17:58:08 +0000 Message-ID: <20130315175808.GT4977@n2100.arm.linux.org.uk> References: <7534695.eTHcH0enMV@wuerfel> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from caramon.arm.linux.org.uk ([78.32.30.218]:36391 "EHLO caramon.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751901Ab3COR6R (ORCPT ); Fri, 15 Mar 2013 13:58:17 -0400 Content-Disposition: inline In-Reply-To: <7534695.eTHcH0enMV@wuerfel> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Arnd Bergmann Cc: linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org On Thu, Mar 14, 2013 at 11:01:35PM +0100, Arnd Bergmann wrote: > gcc-4.7 and higher add a lot of false positive warnings about > potential uses of uninitialized warnings, but only when optimizing > for size (-Os). This is the default when building allyesconfig, > which turns on CONFIG_CC_OPTIMIZE_FOR_SIZE. > > In order to avoid getting a lot of patches that initialize such > variables and accidentally hide real errors along the way, let's > just turn off this warning on the respective gcc versions > when building with size optimizations. The -Wmaybe-uninitialized > option was introduced in the same gcc version (4.7) that is now > causing the false positives, so there is no effect on older compilers. > > A side effect is that when building with CONFIG_CC_OPTIMIZE_FOR_SIZE, > we might now see /fewer/ warnings about possibly uninitialized > warnings than with -O2, but that is still much better than seeing > warnings known to be bogus. What about truely uninitialized uses of variables? Will this hide their warning too?