Re: contribution

Re: contribution

[Toon Moene]

Andi Kleen wrote:

> Alexey Starovoytov <starlex@eng.sun.com> writes:

>> For example SPECfp benchmark 172.mgrid showed 48% improvement
>> compiled with "-O2 -Ws,-O2,-fno-strict-aliasing" vs plain GCC 
>> with "-O2"

> You could compiled 172.mgrid with gcc twice this way and it showed 
> 48% improvement ? Or did you use a different compiler as backend? 
> If you used gcc - is it known where that huge difference comes 
> from? 

A more important aspect of such a compiler would be idempotency.

I.e., is

	gcc(gcc(x.c)) = gcc(x.c)

?

[ Ducks :-) ]

--
Toon Moene, KNMI, PO Box 201, 3730 AE De Bilt, The Netherlands.
Tel. +31302206443, Fax +31302210407,  e-mail moene@knmi.nl
URL: http://www.knmi.nl/hirlam

Contribution

[Mohamed Atef]

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Hello all,
   As I mentioned before, I don't have much time to contribute.
So is there any way I can contribute some medium project I can work on but
myself in the long run? I loved this community, I contributed before so can
you suggest some work for me?

Mohamed

Re: Contribution

[Jason Merrill]

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Hi, thanks for your interest.

There are some ideas at https://gcc.gnu.org/wiki/EasyHacks

You might also look at Bugzilla PRs with a lot of interest, particularly
with severity of "enhancement".  In the search results screen you can
display the number of CCs and duplicates using the "change columns" button
at the bottom.

On Wed, Dec 14, 2022 at 10:33 AM Mohamed Atef via Gcc <gcc@gcc.gnu.org>
wrote:

> Hello all,
>    As I mentioned before, I don't have much time to contribute.
> So is there any way I can contribute some medium project I can work on but
> myself in the long run? I loved this community, I contributed before so can
> you suggest some work for me?
>
> Mohamed
>
>

Re: Contribution

[Paul Smith]

On Wed, 2022-12-14 at 17:32 +0200, Mohamed Atef via Gcc wrote:
> Hello all,
>    As I mentioned before, I don't have much time to contribute.
> So is there any way I can contribute some medium project I can work
> on but myself in the long run? I loved this community, I contributed
> before so can you suggest some work for me?

I don't know if it's on the EasyHacks list but there's this bug with a
patch I filed years ago, that has been asked for multiple times since,
but I've never had the bandwidth to polish and submit it and it looks
like I never will.

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78147

Fwd: Contribution

[farhad]

TO whom it may concern,
I'm Farhad Sarvari and I have been working as a software engineer for more
than 10 years and also have a strong background in c++ programming language.
In addition I wrote a book about modern C++.
<https://leanpub.com/cpplibrary-persian>  I want to contribute to GCC
development. It would be great if you provide more detail about how i can
contribute.
Thanks in advance. I'm looking forward to hearing from you.

Best regards,
Farhad

-- 
sent by Farhad


-- 
sent by Farhad

Re: Contribution

[David Edelsohn]

On Mon, Mar 14, 2022 at 4:37 AM farhad via Gcc <gcc@gcc.gnu.org> wrote:
>
> TO whom it may concern,
> I'm Farhad Sarvari and I have been working as a software engineer for more
> than 10 years and also have a strong background in c++ programming language.
> In addition I wrote a book about modern C++.
> <https://leanpub.com/cpplibrary-persian>  I want to contribute to GCC
> development. It would be great if you provide more detail about how i can
> contribute.
> Thanks in advance. I'm looking forward to hearing from you.

Thanks for your interest in GCC.  Welcome!

A good place to start is the GCC Wiki Getting Started page:
https://gcc.gnu.org/wiki/#Getting_Started_with_GCC_Development

and browse other recent answers to similar questions in the archives
of this mailing list.

Thanks, David

>
> Best regards,
> Farhad
>
> --
> sent by Farhad
>
>
> --
> sent by Farhad

Re: contribution

[Andi Kleen]

Toon Moene <moene@knmi.nl> writes:

> Andi Kleen wrote:
> 
> > Alexey Starovoytov <starlex@eng.sun.com> writes:
> 
> >> For example SPECfp benchmark 172.mgrid showed 48% improvement
> >> compiled with "-O2 -Ws,-O2,-fno-strict-aliasing" vs plain GCC 
> >> with "-O2"
> 
> > You could compiled 172.mgrid with gcc twice this way and it showed 
> > 48% improvement ? Or did you use a different compiler as backend? 
> > If you used gcc - is it known where that huge difference comes 
> > from? 
> 
> A more important aspect of such a compiler would be idempotency.
> 
> I.e., is
> 
> 	gcc(gcc(x.c)) = gcc(x.c)
> 
> ?

To be honest I don't believe that he got that result with multiple runs
of gcc. If yes that would be a very bad bug in the optimizer. More likely
it was reached with the proprietary Sun compiler as backend (that would 
make the patch more a porting tool for GNU C programs to Sun C) 

-Andi

Re: contribution

[Toon Moene]

Andi Kleen wrote:

> > > You could compiled 172.mgrid with gcc twice this way and it showed
> > > 48% improvement ? Or did you use a different compiler as backend?
> > > If you used gcc - is it known where that huge difference comes
> > > from?

> To be honest I don't believe that he got that result with multiple runs
> of gcc. If yes that would be a very bad bug in the optimizer. More likely
> it was reached with the proprietary Sun compiler as backend (that would
> make the patch more a porting tool for GNU C programs to Sun C)

Hmm, I wouldn't be surprised at all ...  When g77 came out (in February
'95) we had a hard time beating the f2c+gcc combo.  It might still be
the case that, e.g., multi-rank array code (as in mgrid) is treated more
optimally by the gcc middle-end when first "squashed" by a Fortran to C
converter into a linear array.

--
Toon Moene, KNMI, PO Box 201, 3730 AE De Bilt, The Netherlands.
Tel. +31302206443, Fax +31302210407,  e-mail moene@knmi.nl
URL: http://www.knmi.nl/hirlam

Re: contribution

[Andi Kleen]

Alexey Starovoytov <starlex@eng.sun.com> writes:

> For example SPECfp benchmark 172.mgrid showed 48% improvement
> compiled with "-O2 -Ws,-O2,-fno-strict-aliasing" vs plain GCC with "-O2"

You could compiled 172.mgrid with gcc twice this way and it showed 48%
improvement ? Or did you use a different compiler as backend? 
If you used gcc - is it known where that huge difference comes from? 

-Andi

Re: contribution

[Alexey Starovoytov]

On 12 Apr 2002, Andi Kleen wrote:

> Alexey Starovoytov <starlex@eng.sun.com> writes:
>
> > For example SPECfp benchmark 172.mgrid showed 48% improvement
> > compiled with "-O2 -Ws,-O2,-fno-strict-aliasing" vs plain GCC with "-O2"
>
> You could compiled 172.mgrid with gcc twice this way and it showed 48%
> improvement ? Or did you use a different compiler as backend?
It was gcc3.0.4 as a backend.

Environment:
US2 450Mhz Solaris 2.8

gcc_3.0.4   -O2:
Success 172.mgrid ratio=59.73, runtime=3013.766979

GCC_3.0.4 -> C -> GCC_3.0.4    -O2 -Ws,-O2,-fno-strict-aliasing
Success 172.mgrid ratio=88.55, runtime=2032.768725

GCC_3.1 -> C -> GCC_3.0.4    -O2 -Ws,-O2,-fno-strict-aliasing
Success 172.mgrid ratio=98.22, runtime=1832.557732

> If you used gcc - is it known where that huge difference comes from?
I didn't have time to check.

Best regards,
Alexey.

Re: contribution

[Toon Moene]

Alexey Starovoytov wrote:

> On 12 Apr 2002, Andi Kleen wrote:

> > You could compiled 172.mgrid with gcc twice this way and it showed 48%
> > improvement ? Or did you use a different compiler as backend?

> It was gcc3.0.4 as a backend.

mgrid is one of those codes that heavily pays for reruning loop
optimisation (as it is now).

At least looking at the generated assembler, g77 -O2 -fno-rerun-loop-opt
produces much better code.

-- 
Toon Moene - mailto:toon@moene.indiv.nluug.nl - phoneto: +31 346 214290
Saturnushof 14, 3738 XG  Maartensdijk, The Netherlands
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