Re: variable reusing

Hello,

On Wed, 15 May 2013 09:35:14 +1200
Daniel Beer <[email protected]> wrote:

> On Tue, May 14, 2013 at 09:26:46PM +0300, Paul Sokolovsky wrote:
> > More interesting question is such support for static (if not global)
> > variables. When trying to do Elliptic Curve Cryptography on MSP430
> > value line devices which top up at 0.5K RAM, you really wish that
> > compiler could "pack" together static buffers of functions which
> > cannot be active at the same time ;-). If anyone know of that to be
> > done by gcc, would be nice to get some pointers.
> 
> If you have static buffers which are never in use simultaneously, why
> not keep them together in a union { }?

Yes, the talk was about offloading the work of proving
non-simultaneous access constraints and creation of that union to the
compiler ;-). Shouldn't be hard for the case of scalar static variables
(function-local dataflow analysis and interprocedural control flow
analysis), so I wondered if someone knows it to be implemented. To be
really useful this should be applied to structural/array vars though,
and that's much harder.

> 
> - Daniel


-- 
Best regards,
 Paul                          mailto:[email protected]

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