+ /// isUnordered - Returns true if this memory operation doesn't have any
+ /// ordering constraints other than normal aliasing. Volatile and atomic
+ /// memory operations can't be reordered.
+ ///
+ /// Currently, we don't model the difference between volatile and atomic
+ /// operations. They should retain their ordering relative to all memory
+ /// operations.
+ bool isUnordered() const { return !isVolatile(); }
+