On 03/25/11 10:39, Richard Guenther wrote:
> On Fri, Mar 25, 2011 at 4:33 PM, Jakub Jelinek<jakub@redhat.com>  wrote:
>> On Fri, Mar 25, 2011 at 09:30:22AM -0600, Jeff Law wrote:
>>> I'm not going to chime in on this specific problem; however, it is worth
>>> noting that many of the issues raised by the C++0x memory model also
>>> affect the linux kernel.
>>
>> But what they are seeing are certainly store data races, not load races,
>> because no hw they care about (or no hw at all?) detects the latter.
>> Having options to avoid store data races is useful not just for C++0x memory
>> model compliance and Linux kernel, but e.g. for OpenMP too.
>
> And we have in the past removed code that created store data races
> anyway.  There is nothing new here.
>
> As stated multiple times in the past things get "interesting" when you
> look at non-x86 hardware.

Agreed on all counts, with everyone :).  I will desist from trying to 
disable speculative loads and load data races which affect no one.

Below is a patch I am committing to remove all tests checking for load 
races.

As Richi has mentioned, there are some interesting store data races on 
non-x86 hardware.  I will be looking into those, particularly non 
contiguous bitfield issues on ppc, s390, and possibly alpha: stay tuned.

Thanks for the comments.