On Tue, Mar 4, 2014 at 10:33 AM, Hannes Frederic Sowa
<han...@stressinduktion.org> wrote:
> On Tue, Mar 04, 2014 at 09:26:31AM +0000, Andrew Haley wrote:
>> On 03/04/2014 09:24 AM, Hannes Frederic Sowa wrote:
>> >> > So the bug was probably fixed more than 15 years ago.
>> > Probably :)
>> >
>> > But the __volatile__ shoud do no harm and shouldn't influence code
>> > generation in any way, no?
>>
>> Of course it will: it's a barrier.
>
> Sure. My question was about the volatile marker. asm("":::"memory") should act
> as the barrier alone.
__asm__("":::"memory")
is a memory barrier
volatile __asm__("":::"memory")
is a memory barrier and a barrier for other volatile instructions.
Nothing more, nothing less.
Neither is a "optimization barrier" or "compiler barrier" or whatever
name you invent.
Richard.
