Re: [RFC/PATCH] powerpc: Always use -mno-string & -mno-multiple

[Benjamin Herrenschmidt <benh@kernel.crashing.org>]

On Thu, 2007-03-22 at 13:02 +0100, Segher Boessenkool wrote:
> > powerpc: Always use -mno-string and -mno-multiple
> >
> > The string and multiple load/store instructions are causing more
> > damage than help on a lot of processors where they are microcoded
> > and are generally no good for the kernel to use. Let's make sure
> > we don't emit them on any powerpc variant.
> 
> And they help a lot on many 32-bit CPUs.  NAK.
> 
> If you tell your GCC to compile for a certain CPU where
> these insns would be very slow, GCC will automagically
> not generate them, already.

multiple do, strings really don't much except maybe on 601.... we don't
quite yet have the options to compile for specific CPUs on arch/powerpc
so -mno-string is a good idea generally, though I agree -mno-multiple
isn't, thus my next patch :-)

Ben.