C WRW+2W+fencembacquireonce+fencembonceonce+Once Hash=d238102c7009a5d1266f9a785edda0f9 Cycle=FenceMbdRWAcquireOnce WseOnceOnce FenceMbdWWOnceOnce WseOnceOnce RfeOnceAcquire Relax=RfeOnceAcquire Safe=FenceMbdWW FenceMbdRW WseOnceOnce Generator=diy7 (version 7.46+3) Prefetch=1:x=F,1:y=W,2:y=F,2:x=W Com=Rf Ws Ws Orig=RfeOnceAcquire FenceMbdRWAcquireOnce WseOnceOnce FenceMbdWWOnceOnce WseOnceOnce {} P0(int* x) { WRITE_ONCE(*x,2); } P1(int* x,int* y) { int r0 = smp_load_acquire(x); smp_mb(); WRITE_ONCE(*y,1); } P2(int* x,int* y) { WRITE_ONCE(*y,2); smp_mb(); WRITE_ONCE(*x,1); } Observed y=2; x=2; 1:r0=2;
C11 equivalent:
C WRW+2W+fencembacquireonce+fencembonceonce+Once Hash=d238102c7009a5d1266f9a785edda0f9 Cycle=FenceMbdRWAcquireOnce WseOnceOnce FenceMbdWWOnceOnce WseOnceOnce RfeOnceAcquire Relax=RfeOnceAcquire Safe=FenceMbdWW FenceMbdRW WseOnceOnce Generator=diy7 (version 7.46+3) Prefetch=1:x=F,1:y=W,2:y=F,2:x=W Com=Rf Ws Ws Orig=RfeOnceAcquire FenceMbdRWAcquireOnce WseOnceOnce FenceMbdWWOnceOnce WseOnceOnce {} P0(atomic_int* x) { atomic_store_explicit(x,2,memory_order_relaxed); } P1(atomic_int* x,atomic_int* y) { int r0 = atomic_load_explicit(x,memory_order_acquire); atomic_thread_fence(memory_order_seq_cst); atomic_store_explicit(y,1,memory_order_relaxed); } P2(atomic_int* x,atomic_int* y) { atomic_store_explicit(y,2,memory_order_relaxed); atomic_thread_fence(memory_order_seq_cst); atomic_store_explicit(x,1,memory_order_relaxed); } exists (x=2 /\ y=2 /\ 1:r0=2)