On Mon, Apr 17, 2023 at 3:17 PM Thiago Macieira via Std-Proposals
<std-proposals_at_[hidden]> wrote:
>
> However, you said "frame pointer" but listed RSP for x86. That's the wrong
> register. The frame pointer on x86 is RBP and it doesn't need to be kept. In
> optimised code, if the compiler can avoid needing RBP for the frame pointer
> and free it instead for a variable, that improves performance, due to the
> shortage of available general-purpose registers. So you cannot count on there
> being a frame pointer on x86.


RBP can look like RSP when one is skimming over a post. I wrote RBP.

Anyway, the use of "std::frame_pointer" inside a function would be an
indicator to the compiler to actually use the frame pointer. If it
really doesn't want to use the frame pointer, it can return nullptr.