I didn't look at the LLVM IR (since I'm not really familiar with it), but I might investigate it a bit further in the near future.

I would encourage it. LLVM IR is fairly easy to understand. One of my first forays into rustc was looking at the IR for iterators to see why one version was show (turned out to be that the bounds on the index variable couldn't proven tight enough to eliminate the bounds check, iirc).

Try writing the same simple code as D and compare the two IR representations.

And no matter how much I slag on rust being difficult, the community is really good about helping and teaching.