From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kyle McMartin Subject: Re: [bug] gcc-4.[23] miscompiling causing networking to bugger up Date: Wed, 28 May 2008 19:00:25 -0400 Message-ID: <20080528230025.GC30501@phobos.i.cabal.ca> References: <20080528190946.GA30501@phobos.i.cabal.ca> <20080528200035.GB30501@phobos.i.cabal.ca> <119aab440805281555n7d16c1ccn4a2d73f267c3b686@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Kyle McMartin , linux-parisc@vger.kernel.org To: Carlos O'Donell Return-path: In-Reply-To: <119aab440805281555n7d16c1ccn4a2d73f267c3b686@mail.gmail.com> List-ID: List-Id: linux-parisc.vger.kernel.org On Wed, May 28, 2008 at 06:55:29PM -0400, Carlos O'Donell wrote: > On Wed, May 28, 2008 at 4:00 PM, Kyle McMartin wrote: > > On Wed, May 28, 2008 at 03:09:46PM -0400, Kyle McMartin wrote: > >> So I've narrowed the regression down to a miscompilation (presumably) of > >> net/ipv4/ip_output.o, in the sense that > >> > >> cp linux-2.6-gcc34/net/ipv4/ip_output.o > >> linux-2.6-gcc43/net/ipv4/ip_output.o > >> touch linux-2.6-gcc43/net/ipv4/ip_output.o > >> make vmlinux > >> > >> fixes the issue. > >> > > > > Apparently I was on glue and gcc-4.2 is not problematic. > > If you compile ip_output.c with -O0 does it work with gcc-4.3? > Building the kernel without optimization is very tetchy... if you can guess what passes to remove, I can try... one of the optimization effects that must go is DCE though, otherwise we'll have undefined references to things (ie: kmalloc_too_much in a switch that should have been eliminated except the constant case.) r, Kyle