On 02/14/2012 09:52 AM, Andrew MacLeod wrote:
> On 02/14/2012 11:28 AM, Jakub Jelinek wrote:
>> On Tue, Feb 14, 2012 at 11:23:58AM -0500, Andrew MacLeod wrote:
>>> This patch just modifies the documention to indicate that the upper
>>> bits of the memory model parameter are reserved for future use.
>>> (We're already looking at using it for HLE hints)
>>>
>>> I've already made a change on the wiki page.
>>>
>>> Ok for mainline?
>> Looks good to me, but would like Richard to chime in too.
>>
>> BTW, I wonder if we shouldn't error out on
>> int
>> foo (int *p)
>> {
>> return __atomic_fetch_add (p, 4, __ATOMIC_SEQ_CST | 0x123400);
>> }
>> (currently we just warn).
>
> I think warning is enough. We're planning to use those reserved bits for
> something else, so we'd be removing the error in the next release anyway.
> The compiler throws those extra bits away now anyway and reverts to SEQ_CST.
>
> I'd say just issue a warning whenever the compiler sees values in that field
> which it doesn't support. So next release if we add 2 HLE flags, we'd add
> warnings if values outside those are used as well.
>
> Andrew
Indeed, that seems good enough to me.
r~
