Richard Guenther <[email protected]> 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
--
[email protected] -- Speaking for myself only
