14.2.4.6.2 Mouth to Mouth, Ear to Ear.

One of the variables is only loaded from, and the other is only stored to. Because (once again, ignoring MMIO registers) it is not possible for one load to see the results of the other, it is not possible to detect the conditional ordering provided by the memory barrier. (Yes, it is possible to determine which store happened last, but this does not depend on the memory barrier.)



Paul E. McKenney 2011-12-16