On Wed, Jul 30, 2008 at 03:08:40PM +1000, Benjamin Herrenschmidt wrote: > On Wed, 2008-07-30 at 15:06 +1000, Michael Ellerman wrote: > > > + > > > +/* > > > + * The performance critical leaf functions are made noinline otherwise > > > gcc > > > + * inlines everything into a single function which results in too much > > > + * register pressure. > > > + */ > > > > This strikes me as something that is liable to change for compiler > > version n+1, or n with -fsomething - and might leave us shooting > > ourselves in the foot, just a thought. > > > > Not that much I'd say... In fact, I wouldn't be too worried on powerpc, > I wonder if that comment is stale from the x86 variant :-) Nick ?
Right... gcc is really poor at over pressuing registers when inlining, and when I checked I don't think it even allocated registers to the inner-most variables in cases such as this. I thought I checked powerpc and sound some spilling there too, but it was quite a long time ago (and yes it was brought over from x86). Should double check. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev