[gnu-linaro-tools] Re: -fremove-local-statics optimization

[Mark Mitchell]

Ulrich Weigand wrote:
> Andrew Stubbs <ams at codesourcery.com> wrote:
> 
>> Some discussion later, they decided it would be better to implement the
>> optimization using inter-procedural dead store analysis:
>>    http://gcc.gnu.org/ml/gcc-patches/2008-07/msg01602.html
> 
> I agree that this would be a much nicer way ...

> Maybe this is something we should be working on then?
> 
>> So basically we're left with this patch that does something we want, but
>> not in a way that can go upstream. :(

For avoidance of doubt, we (CodeSourcery) aren't attached to the current
implementation.  If someone wants us to go do a better one, that would
be fun.  But, on the other hand, the current implementation works, and
delivers a significant improvement on EEMBC.

> The one concern I have is that the patch introduces a user-visible
> construct: the -fremove-local-statics command line option.  If we
> add this now, and users add the flag to their Makefiles, and then
> it goes away later on, users' builds could break.

I think it's reasonable for the option to be named that, no matter what
implementation it has.  At worst, we could always have a Linaro-specific
hack to accept the option and ignore it; certainly, CodeSourcery will
support this command-line option in our tools going forward "forever".

Thanks,

-- 
Mark Mitchell
CodeSourcery
mark at codesourcery.com
(650) 331-3385 x713