[cpp-threads] Brief example ITANIUM Implementation for C/C++MemoryModel

[Peter Dimov]

Alexander Terekhov:

> That would be the case if C/C++ would offer only seq_cst atomic
> operations without any relaxed ones (I mean release/acquire/relaxed).
> But that is not the case under the current draft. So my interpretation
> is based on simple reasoning: seq_cst means fully-fenced (with
> redundant fencing being eligible for removal by optimizers).

I don't think that it does. The C++MM (if my understanding is correct) 
doesn't prohibit load-relaxed (or an ordinary load) sinking below 
load-seq-cst.