Comment 10 for bug 803865

Laurynas,

The usage volatile and memory in this case have very little to do with the asm block itself, inputs/outputs or its side-effects, it's mainly about the context in which it is used. If the atomic intrinsic is being used to implement a locking primitive (e.g. a spinlock), which is the case in MySQL, it's is important to prevent the compiler from reordering across the locked region and to synchronize memory access around it.