Enabling -frename-registers?

[Richard Biener]

On April 29, 2016 3:48:37 PM GMT+02:00, David Edelsohn <dje.gcc@gmail.com> wrote:
>On Fri, Apr 29, 2016 at 9:44 AM, Bernd Schmidt <bschmidt@redhat.com>
>wrote:
>>
>>
>> On 04/29/2016 03:42 PM, David Edelsohn wrote:
>>>
>>> On Fri, Apr 29, 2016 at 9:32 AM, Bernd Schmidt <bschmidt@redhat.com>
>>> wrote:
>>>>
>>>> On 04/29/2016 03:02 PM, David Edelsohn wrote:
>>>>>
>>>>>
>>>>> How has this show general benefit for all architectures to deserve
>>>>> enabling it by default at -O2?
>>>>
>>>>
>>>>
>>>> It should improve postreload scheduling in general, and it can also
>help
>>>> clear up bad code generation left behind by register allocation.
>>>
>>>
>>> Did you test the actual performance benefit on any architectures,
>>> especially architectures other than x86?
>>
>>
>> No. If that's the standard, I'll back out the change.
>
>It seems rather strange to enable an optimization by default across
>all targets without even knowing the performance impact.
>
>I'm eager to learn the opinion of others about this.

It shows overall benefit on Itanic and ups and downs on x86.

It's stage1 and the easiest to get feedback for all archs is to enable it by default.

Richard.

>Thanks, David