[Noob] Docs for SelectionDAGs?

Hi all,

Just getting started with LLVM, and trying to write a back end for a toy hypothetical processor. I'm using llvm-gcc with -emit-llvm to see the LLVM code. The LLVM code is very well-documented at http://llvm.org/docs/LangRef.html. However, I'm looking for equivalent documentation for SelectionDAGs. As I understand it, instructions in the target specification get matched against the SelectionDAGs, not against the LLVM code. So where do I go to ensure that I'm correctly defining everything that needs to be defined?

Thanks,

--Rob

http://llvm.org/docs/CodeGenerator.html#selectiondag_intro should be
enough to get you started.

-Eli