ARM is adding it's CPU architecture list to LLVM/Clang on a daily basis. For Xcode to see it is natural--the update to Xcode will have LLVM/Clang 3.0 with all the ARM additions.
code for an A9 that would be acceptable enough for the macbook air. If they were able to make a smaller thunderbolt chip (hopefully to come). and apple does their magical engineering procedures, a macbook air with a much more powerful ARM chip (not just the one iOS devices use) and a good GPU pair (or just let the ARM chip have the built in GPU) that would be a very powerful computer that I wouldn't mind ditching intel for.
Than again, Ivy Bridge or Trinity, would make very beautiful additions to the product line as well.
I still find it hard to believe that we're talking about a quad-core processor inside a phone! Just a few years ago, I was stunned that one was possible inside a desktop computer.
I think it's too early for a quad core iPad. Apple doesn't need one yet to fend off competition. I'd think in the iPad 4 or 5. It could happen in the 3 but I'd imagine that the number of iPad 1's and 2's that could/would flood the market wouldn't be good for sales of the iPad 3 quad core...
I really do not read much into this as quad core power tablets are expected in 1st Quarter 2012 and quad core phones are expected to be out in 2012 to me it is kind of a "well duh" thing.
I wouldn't guess anything but prototyping. Their internal team has proven themselves more than capable with the A4 and A5.
I also agree with Ars' prediction that A6 will simply be a 28nm die shrink of the A5. Have to save all the power they can to squeeze in a new LTE chip from Qualcomm.