[Joker_vD]

Why is almost no one in this comment thread is willing to face the scenario where the function call has to actually happen, and be an actual function call? The reactions are either "no-no-no-no, the call will be inlined, don't you worry your pretty head" or "well, then the compiler will just use less registers to make less spills" — which precisely agrees with my point that having more registers ain't necessarily all that useful.

> Small scale stuff is you don't usually spill around every call site.

Well duh: it's small, so even just 8 registers is likely enough for it. So again, why bother with cumbersome schemes to extend to 32 registers?

And this problem actually exists, that's why SPARC tried register windows and even crazier schemes on the software side of things had been proposed e.g. [0] — seriously, read this. And it's 30 years old, and IIUC nothing much came out of it so excuse me if I'm somewhat skeptical about "compilers can do better - but it's all a work in progress" claims. Perhaps they already do as best they can for general-purpose CPUs. Good thing we have other kinds processing units readily available nowadays.

[0] David W. Wall, "Global Register Allocation at Link Time", 1986, https://dl.acm.org/doi/10.1145/12276.13338