[llvm-dev] Use Global ISel or SelectionDAG

[Matt Arsenault via llvm-dev]

> On Feb 13, 2020, at 17:08, floris westermann via llvm-dev <llvm-dev at lists.llvm.org> wrote:
> 
> Hi llvm-dev,
> 
> I am currently writing a backend for an architecture I am designing in my bachelor's thesis and recently came across the GlobalISel Selection Framework. 
> Should already start using this over the more common Selection DAG?
> Being new llvm backend development, I am not sure if GlobalISel would be "easier" to implement than ISelDAG and if there is any decent documentation on how to do so.
> 
> Cheers,
> Floris

I think it depends on how much you care about optimization, how weird your target is, and how long you plan to maintain it. If you don’t care about optimization, and have a very strange target, you would probably be better off with GlobalISel. There will be fewer examples to work with however.

-Matt