From: gabx <arnaud.gaboury@gmail.com>
To: crossgcc@sourceware.org
Subject: Re: gcc CXX_FLAGS
Date: Wed, 29 May 2013 09:02:00 -0000 [thread overview]
Message-ID: <CAK1hC9tryU2BU-s5D1QB4F-L-NU2rG9vm4+n+=v0qjx4Nuxo=w@mail.gmail.com> (raw)
In-Reply-To: <CAL4-wQpjBs1DD7SjtFYGzGtTRvWa4Ar-cc-J5k9msDmNq1mW7Q@mail.gmail.com>
On Wed, May 29, 2013 at 9:24 AM, Martin Guy-2 [via Sourceware.org] <
ml-node+s1504n233506h65@n7.nabble.com> wrote:
> On 28 May 2013 19:31, gabx <[hidden email]<http://user/SendEmail.jtp?type=node&node=233506&i=0>>
> wrote:
> > Thank you all for these details. It is my first deep journey in the
> > toolchain world, and as described on the ct-ng website, it can quickly
> > become a nightmare.
>
> Not a nightmare. It's just that compilers are complex. cross-compiler
> even more so.
>
> > I guess my CCX_FLAGS is then a non-sense :
>
> Not nonsense. You just have a super-fast cross-compiler that generates
> the same code as a regular one!
>
> > Which flags would you keep ?
> > My toolchain is aimed at building android kernel and rom for the Google
> LG
> > nexus 4.
>
> It depends what you are trying to achieve. If it's just a few % extra
> speed, try -Os or -O2/-O3. I think the manual says they optimise for
> minimum code size or maximum speed without/with large increases in
> compile time and code size, respectively.
> Beyond telling the compiler the instruction set it can use, which
> should correspond to the silicon in your target device, there is only
> a few % speed to be had by juggling with magic options, and which help
> and which make it worse or produce non-working code depend on the
> specific program you are compiling.
>
> M
>
>
>
Thank you Martin.
The unique goal of this toolchain is to build android kernel and rom with
gcc 4.8 and some optimization flags for the Google LG nexus 4 (armv7-a
rev2)
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prev parent reply other threads:[~2013-05-29 9:02 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-25 14:01 gabx
2013-05-25 18:43 ` Anthony Foiani
2013-05-25 22:59 ` gabx
2013-05-25 23:07 ` Yann E. MORIN
2013-05-26 1:42 ` Anthony Foiani
2013-05-26 12:51 ` Martin Guy
2013-05-28 17:31 ` gabx
2013-05-29 7:23 ` Martin Guy
2013-05-29 9:02 ` gabx [this message]
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