LRB midpath code quality

[Roman Kennke]

>> Also, I don't think we want to generate an NPE/SEGV on that path. We
>> want to skip a bunch of stuff if the value is NULL.
> 
> We don't generate an NullPointerException and we almost never have a
> sigsev as it's a path where no null have been seen.

Ah. So it speculates on non-NULL, and then deopts and recompiles if that 
assumption turns out be be wrong?

In this case I agree: let's do it in midpath, using implicit null-check. 
But the issue remains: if we *do* get a NULL then we need to catch it 
before the cset-check? Or am I still missing something?

Also, any idea how we could turn that explicit null-check into an 
implicit one?

Roman