[LLVMdev] New backend help request.

[David Chisnall]

On 9 Jul 2015, at 15:30, James Boulton <eiconic at googlemail.com> wrote:
> 
> Hmm, I'm getting nowhere pretty fast. It seems 68000 with its CISC nature is quite complex to implement for a novice.

As I said before, there’s a big difference between generating working m68k code and generating code that makes optimal use of the instruction set.  I’d aim to get the former working first - use fairly naive mappings to instructions - and then look at peephole optimisations once you have some concrete cases of suboptimal code.  It’s quite easy to have SelectionDAG emit instructions that are correct and then clean them up when you’re in the SSA machine instruction form.

David