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| C LB+fencembonceonce+ctrlonceonce
|
| (*
| * Result: Never
| *
| * This litmus test demonstrates that lightweight ordering suffices for
| * the load-buffering pattern, in other words, preventing all processes
| * reading from the preceding process's write. In this example, the
| * combination of a control dependency and a full memory barrier are enough
| * to do the trick. (But the full memory barrier could be replaced with
| * another control dependency and order would still be maintained.)
| *)
|
| {}
|
| P0(int *x, int *y)
| {
| int r0;
|
| r0 = READ_ONCE(*x);
| if (r0)
| WRITE_ONCE(*y, 1);
| }
|
| P1(int *x, int *y)
| {
| int r0;
|
| r0 = READ_ONCE(*y);
| smp_mb();
| WRITE_ONCE(*x, 1);
| }
|
| exists (0:r0=1 /\ 1:r0=1)
|
|
