It does not matter if there are any architectures like that. Relying on that fact is still an undefined behavior. The compiler is allowed to produce any code it

It does not matter if there are any architectures like that. Relying on that fact is still an undefined behavior. The compiler is allowed to produce any code it wants. If you use memset to initialize structure with pointers with 0 and then test if the pointer are NULL, the compiler could assume that the pointer was not properly initialized and remove the if completely, or actually even remove the whole function.