@corona10 you're certainly welcome to take a look, but if you're looking for low-hanging fruit issues to work on, this isn't a good candidate. It likely requires someone with a good understanding of the compiler, and it's not a simple fix, as @josharian already gave that a try.
Oh.. @josharian already tried it. Looks like a not simple issue.
I thought it was just an issue of rewriting so that it can help the compiler to do a mid stack inlining, but I did not know that cost was an issue to consider. I will try to find some easier issues.