Question about simple_return pattern for the GCC ARM backend.

Question about simple_return pattern for the GCC ARM backend.

[Yangfei (Felix)]

Hi, 

  I think that simple_return standard pattern is useful for the ARM. I mean it should be good for target code performance.
　But seems this pattern is not there for the GCC ARM backend. Can anyone explain the reason why we don’t need this?

Cheers,
Fei

Re: Question about simple_return pattern for the GCC ARM backend.

[Chung-Lin Tang]

On 2013/12/28 09:31 AM, Yangfei (Felix) wrote:
> Hi, 
> 
>   I think that simple_return standard pattern is useful for the ARM. I mean it should be good for target code performance.
> 　But seems this pattern is not there for the GCC ARM backend. Can anyone explain the reason why we don’t need this?
> 
> Cheers,
> Fei
> 

It does use it. Search for the "<return_str>return" expand pattern, and
the "returns" code iterator in config/arm/iterators.md.

Chung-Lin

Re: Question about simple_return pattern for the GCC ARM backend.

[Yangfei (Felix)]

Thanks for the reply. I found it in GCC-4.8. 
The gcc version I look at is GCC-4.7. Seems this pattern is not there for this version.

> 
> On 2013/12/28 09:31 AM, Yangfei (Felix) wrote:
> > Hi,
> >
> >   I think that simple_return standard pattern is useful for the ARM. I mean
> it should be good for target code performance.
> > 　But seems this pattern is not there for the GCC ARM backend. Can anyone
> explain the reason why we don’t need this?
> >
> > Cheers,
> > Fei
> >
> 
> It does use it. Search for the "<return_str>return" expand pattern, and the
> "returns" code iterator in config/arm/iterators.md.
> 
> Chung-Lin

Re: Question about simple_return pattern for the GCC ARM backend.

[Ramana Radhakrishnan]

On Mon, Dec 30, 2013 at 3:23 AM, Yangfei (Felix) <felix.yang@huawei.com> wrote:
> Thanks for the reply. I found it in GCC-4.8.
> The gcc version I look at is GCC-4.7. Seems this pattern is not there for this version.

That will be because this was added in time for GCC 4.8. If you need
to find such information as to when something was added please look
into Changelog* files and / or look on the gcc-patches archive. In
this case you need to look for a patch that enables shrink wrapping
for ARM.

Also, checking whether certain features are present or not in the
source tree are best checked in the trunk sources since that is where
new development happens.

Thanks,
Ramana

>
>>
>> On 2013/12/28 09:31 AM, Yangfei (Felix) wrote:
>> > Hi,
>> >
>> >   I think that simple_return standard pattern is useful for the ARM. I mean
>> it should be good for target code performance.
>> >　 But seems this pattern is not there for the GCC ARM backend. Can anyone
>> explain the reason why we don’t need this?
>> >
>> > Cheers,
>> > Fei
>> >
>>
>> It does use it. Search for the "<return_str>return" expand pattern, and the
>> "returns" code iterator in config/arm/iterators.md.
>>
>> Chung-Lin
>