Common ancestor in merge diffs?

I was just doing an annoying merge (I'd reorganized code while other people made changes to it), and I kept having the problem that it was hard to figure out what each side had done. Is there some way to ask git for the diffs between the common ancestor (which is unique in my case, so it's actually useful) and each of the sides of the merge? Ideally, it would give essentially the converse of the --cc diff: first column is -stage 1 +stage 2; second column is -stage 1 +stage 3.

I think this would generally be more useful than the current diff output for the unresolved portions (-stage 3 +working tree, -stage 2 +working tree) because you're generally quite familiar with the working tree (since you're trying to resolve there), and stage 1 is not obvious.

	-Daniel
*This .sig left intentionally blank*