Re: [PATCH] doc: discourage use of __attribute__((optimize())) in production code

[Markus Trippelsdorf <markus@trippelsdorf.de>]

On 2015.12.14 at 11:20 -0500, Trevor Saunders wrote:
> On Mon, Dec 14, 2015 at 10:01:27AM +0100, Richard Biener wrote:
> > On Sun, Dec 13, 2015 at 9:03 PM, Andi Kleen <andi@firstfloor.org> wrote:
> > > Markus Trippelsdorf <markus@trippelsdorf.de> writes:
> > >
> > >> Many developers are still using __attribute__((optimize())) in
> > >> production code, although it quite broken.
> > >
> > > Wo reads documentation? @) If you want to discourage it better warn once
> > > at runtime.
> > 
> > We're also quite heavily using it in LTO internally now.
> 
> besides that does this really make sense?  I suspect very few people are
> using this for the fun of it.  I'd guess most usage is to disable
> optimizations to work around bugs, or maybe trying to get a very hot
> function optimized more.  Either way I suspect its only used by people
> with good reason and this would just really iritate them.

Well, if you look at bugzilla you'll find several wrong code bugs caused
by this attribute, e.g.: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59262

Also Richi stated in the past (I quote):
»I consider the optimize attribute code seriously broken and
unmaintained (but sometimes useful for debugging - and only that).«

https://gcc.gnu.org/ml/gcc/2012-07/msg00201.html

-- 
Markus