Which is even more vague (and broad) than what I was talking about. Given that we are talking about converting recursive algorithms into iterative versions that nevertheless use a stack datastructure, the comparison between the machine stack (used for recursion) and a program-defined stack is a perfectly appropriate criteria to evaluate your vague statement. I gave specific microarchitectural reasons why I predict the machine stack will be faster and you responded (a fairly reasonable response) that we should measure. So please do. I'm not the one making broad claims so the burden of proof still lies on you.
It is a pure fact that the stack is not free. That it is heavily optimized is itself proof of the fact; you don't optimize what is already free.
And, especially for heavily optimized features, you can only meaningfully measure specific cases, so generalizing is generally wrong. Which was the point of my remark.
Which is even more vague (and broad) than what I was talking about. Given that we are talking about converting recursive algorithms into iterative versions that nevertheless use a stack datastructure, the comparison between the machine stack (used for recursion) and a program-defined stack is a perfectly appropriate criteria to evaluate your vague statement. I gave specific microarchitectural reasons why I predict the machine stack will be faster and you responded (a fairly reasonable response) that we should measure. So please do. I'm not the one making broad claims so the burden of proof still lies on you.