valhalla/valhalla/hotspot: multiple value return caused interpreter performance regression

[Roland Westrelin]

Hi Sergey,

> I've just realized that this patch causes more than 3x time interpreter 
> performance regression (if method contains local variable of value type).
>
> Question to all: How big INTERPRETER performance regression will be 
> considered as OK?

Thanks for the performance number. My change adds 2 runtime calls on
method returns with a value type from interpreted callee to interpreted
caller so a big performance drop is not surprising.

My understanding is that we don't care too much about interpreter
performance at this point. In any case, I would rather wait for
Frederic's buffering change to be pushed before considering any
improvement to the vreturn implementation.

Roland.