Michael Matz wrote:
if (condition)
*p = value;
(i.e. without any synchronization primitive or in fact anything else after
the store in the control region) and expect that the store indeed only
happens in that control region. And this expectation is misguided. Had
they written it like:
if (condition) {
*p = value;
membarrier();
}
it would have worked just fine.
Don't you need the barrier before. This is to ensure it completed the
condition test completely first before it then processed the assignment
expression.
if(condition) {
somebarrier();
*p = value;
}
The issue is not that the store is done too late, but that a
write-access is done too early.
Darryl
