This is the mail archive of the
gcc-patches@gcc.gnu.org
mailing list for the GCC project.
Re: [PATCH,rs6000] Add built-in function support Power9 binary floating point operations
On 08/05/2016 08:04 PM, Segher Boessenkool wrote:
> On Fri, Aug 05, 2016 at 04:27:36PM -0500, Pat Haugen wrote:
>> On 08/02/2016 03:15 PM, Segher Boessenkool wrote:
>>> On Tue, Aug 02, 2016 at 03:03:42PM -0500, Pat Haugen wrote:
>>>> On 07/29/2016 10:47 AM, Kelvin Nilsen wrote:
>>>>> + "xsxexpdp %0,%x1"
>>>>> + [(set_attr "type" "fp")])
>>>>
>>>> Type should be 'integer'.
>>>
>>> It has VSX regs as input, integer is worse than fpsimple here, I think?
>>> Or vecsimple, that seems better yes.
>>
>> It's a 2 cycle op that executes in the ALU pipe, just like other integer ops. vecsimple would be worse since those consume a superslice, which this op doesn't.
>>
>
> Ah yes. But why not fpsimple? It schedules the same as e.g. fmr and
> fabs?
>
The subtle difference is that since it has a GPR target it does not restrict a tuple (3 insns) from being dispatched to a superslice, whereas fpsimple ops do.
-Pat