Daniel Gustafsson <daniel@xxxxxxxx> writes: > They are known to be zero, but that's not entirely equivalent though is it? > NIL is defined as ((List *) NULL) and NULL is typically defined as ((void *) > 0), so sizeof(0) would be the size of an int and sizeof(NULL) would be the size > of a void pointer. There are other places where we assume that a memset-to-zero will produce null pointers, so I don't think that that objection has a lot of force. My real answer is that this is our coding style and we are not going to change it: our normal convention is to initialize struct fields in declaration order, and that's what we're doing here. If some particular version of some particular compiler fails to make an entirely-negligible optimization in consequence, that is not something we are going to care about. Maybe we would care if the missed optimization were a serious performance loss in a very hot code path. But this is neither. I'd also say that this is pretty clearly a compiler bug. If it'd normally optimize away a null-pointer-store following a memset-to-zero, but does not in memset(&dpns, 0, sizeof(dpns)); dpns.rtable = rtable; dpns.subplans = NIL; dpns.ctes = NIL; dpns.appendrels = NULL; that would seem to indicate that the optimizer doesn't really understand that dpns.rtable is a distinct field from the others. How is that our problem? (I kind of wonder if what's actually blocking the optimization is the casts inside the NIL macros. Still not our problem.) regards, tom lane
