[cpp-threads] Alternatives to SC

[Doug Lea]

Doug Lea wrote:

> And further, if we had
>    T1                T2                  T3
>    e; wx{x=1}       rx{r1=x}; wy(y=1}    ry{r2=y}
> we'd eventually get e --> ry
> 

Oops. Not e --> ry directly. But it is contained in
T1's transitive closure, which is is required to be acyclic.

-Doug