On Mon, Feb 18, 2008 at 03:57:10PM -0500, Daniel Jacobowitz wrote:
> On Mon, Feb 18, 2008 at 03:25:03PM -0500, Jakub Jelinek wrote:
> > What would break if in non-altivec ABI all Altivec registers are either
> > fixed (-mno-altivec) or call-used (-maltivec)?
>
> I still suggest that the correct choice is to use the same set of
> call-used and call-saved registers without the AltiVec ABI as we do
> with it. Which has no affect with -mno-altivec, but requires some
> prologue work with -maltivec -mabi=no-altivec. After that, whether
> the default ABI is AltiVec or not does not much matter to GCC.
That can work too, assuming on ppc-linux we can rely the kernel and libc
handle saving/restoring the altivec regs (guess we can rely on it these
days). All I'm trying to say is that having an option combination where
some registers are neither fixed, nor call-used, nor call-saved
is a bug (in the current -m32 -maltivec case I think they are officially
call-saved, but nothing saves/restores them).
Jakub
