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Re: Discussion: What is unspec_volatile?
On Sat, Nov 13, 2010 at 8:20 AM, Paolo Bonzini <bonzini@gnu.org> wrote:
> On 11/13/2010 05:10 PM, H.J. Lu wrote:
>>
>> On Sat, Nov 13, 2010 at 8:01 AM, Paolo Bonzini<bonzini@gnu.org> ?wrote:
>>>
>>> On 11/13/2010 04:28 PM, H.J. Lu wrote:
>>>>
>>>> VZEROUPPER is no-nop to executions. But it isn't no-nop for performance.
>>>
>>> IIUC it's a noop as GCC uses it. ?You could use it in 256-bit mode and it
>>> would be valid, but not a noop.
>>>
>>
>> That is besides the point. I just pointed out that there was no register
>> barrier
>> for IRA.
>
> And I was pointing out that the machine description is wrong :)
>
Please tell me how I can tell IRA not to move ANY instructions
across an instruction which is an no-op to executions.
--
H.J.