testing support loops with long (64b) trip counts

[Roland Westrelin]

Hi Maurizio,

Thanks for giving the patch a try.

> Overall, unless I did some mistake, it doesn't look like the patch is 
> changing much. The baseline + workaround for small segment remains the 
> fastest version around, which performs on par with unsafe. If we remove 
> the workaround, we get some 1.5-2x slower; but if we start looping on 
> longs (see the LoopOverNonConstantLong suite), then performances get 
> much, much worse.
>
> Am I missing something? Is our implementation doing something that is 
> confusing your optimization?

I'll take a look at the benchmarks. With the current patch, elimination
of range checks are unlikely to happen. That's follow up work. Could
that be the problem?

Roland.