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Re: [PATCH] data prefetch support and __builtin_prefetch (take 2)
> > > 1) The arm.md already has a "prefetch" expander that takes a different
> > > number of arguments. (I can fix this, but it should have been fixed in
> > > the above check-in).
> > Sorry, I should have done more searching for possible conflicts. Let's
> > get the next piece figured out and then you can let me know whether you
> > want me to fix this or do it yourself.
> As much as anything, these problems should have been caught during the
> review process; particularly as this defines a new generic builtin. I've
> been away for the last month, so out of touch. How thoroughly was the
> spec for this builtin examined? It wouldn't be good if we found we needed
Janis did quite in depth searching for possible alternatives and I believe
his sollution covers all cases, except for somewhat weird Altivec scheme
that can be (should be) covered by specialized builtin.
> a further argument a couple of releases from now.
> With respect to the internal problems, I'll fix them -- I've probably got
> more facilities for testing the ARM changes than you have ;-)
> > > 2) ARM targets already have a __builtin_prefetch function that takes one
> > > argument; as far as I can tell your new implementation will mean an API
> > > change for users of gcc-3.0
> > I looked through all of the documentation to see if there was existing
> > prefetch support and all I found was __builtin_ia32_prefetch. Now I'll
> > know to look through the target-dependent code, too, for undocumented
> > builtin functions.
> > I suppose it's too much to hope for that since it's not documented, no
> > one knows about it and it's not being used.
> Possibly, I've no idea. I think it was the Cygnus/Red Hat guys who added
> this. Nick, any idea if this feature is widely used by your customers?
They still can use #define if we provide __builtin_arm_prefetch