How do I tell gcc that my inline assembly merges part of the stack?

Question

Consider the built-in assembly as follows:

uint64_t flags;
asm ("pushf\n\tpop %0" : "=rm"(flags) : : /* ??? */);

Despite the fact that there is probably some kind of internal problem to get the contents of RFLAGS, how can I tell the compiler that my built-in assembly compresses one square number of memory at the top of the stack?

Answer 1

As far as I know, this is currently not possible.