Re: [PATCH 4/4] xen/arm: correctly handle an empty array of platform descs.

From: "Jan Beulich" <JBeulich@suse.com>
To: Ian Campbell <Ian.Campbell@citrix.com>
Cc: "Keir (Xen.org)" <keir@xen.org>,
	Stefano Stabellini <Stefano.Stabellini@eu.citrix.com>,
	Ian Jackson <Ian.Jackson@eu.citrix.com>,
	"Tim (Xen.org)" <tim@xen.org>,
	"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>,
	Julien Grall <julien.grall@citrix.com>
Subject: Re: [PATCH 4/4] xen/arm: correctly handle an empty array of platform descs.
Date: Tue, 14 May 2013 16:11:59 +0100	[thread overview]
Message-ID: <5192705F02000078000D6179@nat28.tlf.novell.com> (raw)
In-Reply-To: <1368543272.14264.41.camel@zakaz.uk.xensource.com>

>>> On 14.05.13 at 16:54, Ian Campbell <Ian.Campbell@citrix.com> wrote:
> On Tue, 2013-05-14 at 15:29 +0100, Jan Beulich wrote:
>> What compiler version and switches were you using for the case
>> where you spotted bad code to be generated?
> 
> gcc-linaro-aarch64-linux-gnu-4.7-2013.01-20130125_linux doing a standard
> arm64 build of Xen.

Odd - I'm using mostly unmodified 4.7.3 from gcc.gnu.org, so I'm
wondering if that Linaro build has meaningful extra patches and/or
lacks important bug fixes.

The reason I'm trying to get to the bottom of this is because, as
you noted, we might be on the edge of running into more issues
if at least some not know broken gcc versions behave like this.

Could you try compiling the example code I sent earlier with the
two arm compilers you use, to see if that trivial piece of code also
exposes that behavior (or whether this is tied to something else)?

Jan