[sjs]

As Mike Pall said: "None of the benchmarks make use of JavaScript's weird corners. And all of them can (or could) be reduced to simple constructs. So I wouldn't blame it on the language differences alone (maybe on the implementation)."

Only the use of such a feature should trip the "do it the safe but slow way" switch. Maybe that's not possible here though, I don't know that much about compiler optimization.

edit: I'm not implying it's easy either, but if it's possible the V8 team has the skills to implement it.