Re: Question regarding upValues in closures

["Alex Davies" <alex.mania@...>]

Roberto Ierusalimschy wrote:
> Unfortunately, with a one-pass compiler, by the time a return is compiled
> we cannot be sure that there won't be a sub-proto later. For instance,
> consider a code like this:

It can be implemented in the vm though, try benching the current 
implementation:

if (L->openupval) luaF_close(L, base);
vs
if (L->openupval && cl->p->p) luaF_close(L, base);
or
if (cl->p->p) luaF_close(L, base);

Although probably a minor point in real world use, is quite measurable on 
the recursion compiler shootout benches. (And yes, probably is a bad idea to 
optimize a vm based on synthetic benchmarks, but interesting nonetheless?). 
(may make more sense to simply rewrite those code pieces such that they 
close all upvalues before running the functions, which results in similar 
speedup).

- Alex