Missed loop unwind

[bearophile]

David Nadlinger:

> I don't think anything is likely to happen here on the LDC 
> side, as it seems to be a question of tuning the LLVM optimizer.

I was busy for few days, but now I have asked in the llvm 
channel, and the answer is that currently (unlike GDC) llvm 
doesn't unroll loops with multiple exits (it might break, it 
might not; so there are multiple possible exits).

They know about this limitation so perhaps there's not much point 
in opening a LLVM enhancement request.

Bye,
bearophile