C Z6.3+fencembreleaseonce+fencewmbreleaseonce+fencembacquireonce Hash=81d7b172ae9a1b5f4a4631efa464ada6 Cycle=FenceMbdRRAcquireOnce FreOnceRelease FenceMbdWWReleaseOnce WseOnceRelease FenceWmbdWWReleaseOnce RfeOnceAcquire Relax=RfeOnceAcquire FreOnceRelease WseOnceRelease Safe=FenceMbdWW FenceMbdRR FenceWmbdWW Generator=diy7 (version 7.46+3) Prefetch=0:x=F,0:y=W,1:y=F,1:z=W,2:z=F,2:x=T Com=Ws Rf Fr Orig=FenceMbdWWReleaseOnce WseOnceRelease FenceWmbdWWReleaseOnce RfeOnceAcquire FenceMbdRRAcquireOnce FreOnceRelease {} P0(int* x,int* y) { smp_store_release(x,1); smp_mb(); WRITE_ONCE(*y,1); } P1(int* y,int* z) { smp_store_release(y,2); smp_wmb(); WRITE_ONCE(*z,1); } P2(int* x,int* z) { int r0 = smp_load_acquire(z); smp_mb(); int r1 = READ_ONCE(*x); } Observed y=2; 2:r1=0; 2:r0=1;
C11 equivalent:
C Z6.3+fencembreleaseonce+fencewmbreleaseonce+fencembacquireonce Hash=81d7b172ae9a1b5f4a4631efa464ada6 Cycle=FenceMbdRRAcquireOnce FreOnceRelease FenceMbdWWReleaseOnce WseOnceRelease FenceWmbdWWReleaseOnce RfeOnceAcquire Relax=RfeOnceAcquire FreOnceRelease WseOnceRelease Safe=FenceMbdWW FenceMbdRR FenceWmbdWW Generator=diy7 (version 7.46+3) Prefetch=0:x=F,0:y=W,1:y=F,1:z=W,2:z=F,2:x=T Com=Ws Rf Fr Orig=FenceMbdWWReleaseOnce WseOnceRelease FenceWmbdWWReleaseOnce RfeOnceAcquire FenceMbdRRAcquireOnce FreOnceRelease {} P0(atomic_int* x,atomic_int* y) { atomic_store_explicit(x,1,memory_order_release); atomic_thread_fence(memory_order_seq_cst); atomic_store_explicit(y,1,memory_order_relaxed); } P1(atomic_int* y,atomic_int* z) { atomic_store_explicit(y,2,memory_order_release); atomic_thread_fence(memory_order_acq_rel); atomic_store_explicit(z,1,memory_order_relaxed); } P2(atomic_int* x,atomic_int* z) { int r0 = atomic_load_explicit(z,memory_order_acquire); atomic_thread_fence(memory_order_seq_cst); int r1 = atomic_load_explicit(x,memory_order_relaxed); } exists (y=2 /\ 2:r0=1 /\ 2:r1=0)