Re: [avr-gcc-list] Register Allocation -fnew-ra

[Rolf Ebert]

Am Tue, 22 Aug 2006 20:56:55 +0200 schrieb Eric Weddington  
<address@hidden>:

> > However, hunting around the web, I came across this new option -fnew-
> > ra that uses a different register allocation algorithm.
> > I am able to successfully build my application with this option.
> > But it looks like this option is not supported in the newer versions
> > of gcc.
> > Is there any reason for removing -fnew-ra option or is avr-gcc 4.0
> > using -fnew-ra as a default option now ?
>
> Yes. -fnew-ra never worked properly in the first place and hence was  
> removed for good. Please do not use this option.

It never worked properly on Intel x86, it worked quite well on AVRs most  
of the time.  It produces considerably better code than the std RA for  
AVR.  But be careful and completely review the generatd code.  I once had  
a case when new-ra generated wrong code!  In the end, follow Eric's advice  
and don't use it.

   Rolf