[cfe-dev] Clang incorrectly optimizing out for conditional in Linux

[Derrick McKee via cfe-dev]

In the meanwhile, were you able to talk with the implementer about your
proposed change, Erich?  If you and the implementer agree on your fix,
maybe I can add it to my source and get going on my work.

On Tue, Apr 4, 2017 at 11:25 AM Keane, Erich <erich.keane at intel.com> wrote:

> Well Blarg, that is disappointing.  In THIS case, I at least have a hope,
> the original implementer and I share an organization, so hopefully he'll be
> willing to fix it out of internal good will :)
>
> -----Original Message-----
> From: Dr D. Chisnall [mailto:dc552 at hermes.cam.ac.uk] On Behalf Of David
> Chisnall
> Sent: Tuesday, April 4, 2017 1:01 AM
> To: Keane, Erich <erich.keane at intel.com>
> Cc: cfe-dev at lists.llvm.org; derrick.mckee at gmail.com;
> jonathan at codesourcery.com; csong at cs.ucr.edu
> Subject: Re: [cfe-dev] Clang incorrectly optimizing out for conditional in
> Linux
>
> On 3 Apr 2017, at 20:24, Keane, Erich via cfe-dev <cfe-dev at lists.llvm.org>
> wrote:
> >
> > I filed an issue with the Kernel (here
> https://bugzilla.kernel.org/show_bug.cgi?id=195235) to capture this
> issue.  Hopefully this is something that they will fix!  I'll note that my
> suggested answer assumes they want the behavior to remain the same, though
> I'm not sure that is what they MEANT.
>
> As I recall, this particular kernel idiom is one that caused GCC to add an
> extra flag to restrict their optimisations, because rewriting Linux in C
> was harder than hacking the compiler to support Linux-flavoured almost-C,
> so I wouldn’t hold out much hope for Linux fixing the code - this is far
> from the only place that this idiom occurs and has been the cause of at
> least one security vulnerability.
>
> David
>
> --
Derrick McKee
Ph.D. Student at Purdue University
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/cfe-dev/attachments/20170404/e76fcb1f/attachment.html>