Created attachment 245646 [details]
Comment on attachment 245646 [details]
Please run the benchmarks before landing this.
Created attachment 245651 [details]
Caught a bug: You need to test is_object and is_function since is_object only tests "typeof x == 'object'", which doesn't cover functions.
Comment on attachment 245651 [details]
Created attachment 245659 [details]
performance test results
I'd call this neutral. The fluctuating speedups and slowdowns don't hit this code path.
Committed r179372: <http://trac.webkit.org/changeset/179372>