alt Hacker NewsEver heard of a loop that needed to keep more than 7 variables live? Register renaming helps with pipelining and out-of-order execution, but instructions in the program can only reference the architectural registers - go beyond that and you end up needing to spill some values to (architectural) memory.
There's a reason why AMD added r8-r15 to the architecture, and why intel is adding r16-r31..
I have but that was not the point? My first point was exactly that there are more ISA registers and not only 8, and therefore the question mark. My second point was about register renaming which, contrary what you say, does mitigate the artifacts of running out of registers by spilling the variables to the stack memory. It does it by eliminating the false dependencies between variables/registers and xor eax, eax is a great candidate for that.