> that a simple backflow analysis wouldn’t reveal Famous last words, "simple". What about sequences like: pushfd pop eax and eax, ebx Now you need t

> that a simple backflow analysis wouldn’t reveal Famous last words, "simple". What about sequences like: pushfd pop eax and eax, ebx Now you need to know what ebx is to know for certain that PF and AF are irrelevant. Which is very likely, but not guaranteed, and the halting problem rears its ugly head. I don't know whether there are good heuristics there or even how common that really is, but my gut feeling is that it may still be easy to "accidentally" drop into the slow AF/PF-preserving case, which can hurt in performance-critical code. On the other hand, calculating AF/PF in hardware in the first place seems, from my outside view at least, much simpler, and appears to prevent a great deal of potential headache.