switches in GCC JIT?

[David Malcolm]

On Mon, 2015-06-22 at 23:40 +0200, Basile Starynkevitch wrote:
> Hello David & all
> 
> I'm guessing that GCCJIT is able to emit switch like statements, e.g. 
> using GIMPLE_SWITCH statements
> internally.

No, it doesn't.

> But I don't understand how is it possible. It looks like 
> gimple_build_switch does not occur in gcc/jit/

Currently gcc/jit builds functions at the tree level and hands them off
to the gimplifier, so you wouldn't see that in any case.  (in theory it
could be ported to directly generate gimple).

> Are switch statements omitted from GCCJIT? 

Yes.

> If yes, why???

I intentionally didn't implement them, to keep the API simpler.

I've never run into a need for them when implementing jit-compilation,
and in theory they could be implemented using conditionals (albeit
without the nice optimizations that we have for lowering GIMPLE_SWITCH).

There was some discussion about this here:
 https://gcc.gnu.org/ml/jit/2014-q4/msg00116.html

> David, do you intend to improve that?

Do you have a use-case for them?  We can add them if we need them.

Dave