Richard Guenther <richard.guent...@gmail.com> writes: > > To make it a compiler memory barrier you have to "expand" the > builtin already in the frontend and present the middle-end with > __asm__ ("...." : : : "memory"). That will serve as a compiler
Those are the intended semantics (at least those I asked for :-). For all practical purposes the same as asm volatile("pause" ::: "memory") HJ? Can it be expanded earlier? As for why having a builtin: one reason would be portability. Various other architectures have a similar instruction (e.g. PPC). They could be added later to this as a next step. Then it also seems cleaner to me to cover the instruction set with builtins like the others. -Andi -- a...@linux.intel.com -- Speaking for myself only