C Z6.1+fencembonceonce+fencemboncerelease+poacquirerelease Hash=b345ce574bc1ebec7ef82c799f6e5a3d Cycle=PodRWAcquireRelease WseReleaseOnce FenceMbdWWOnceOnce WseOnceOnce FenceMbdWWOnceRelease RfeReleaseAcquire Relax=RfeReleaseAcquire WseReleaseOnce Safe=FenceMbdWW PodRWAcquireRelease WseOnceOnce Generator=diy7 (version 7.46+3) Prefetch=0:x=F,0:y=W,1:y=F,1:z=W,2:z=F,2:x=W Com=Ws Rf Ws Orig=FenceMbdWWOnceOnce WseOnceOnce FenceMbdWWOnceRelease RfeReleaseAcquire PodRWAcquireRelease WseReleaseOnce {} P0(int* x,int* y) { WRITE_ONCE(*x,2); smp_mb(); WRITE_ONCE(*y,1); } P1(int* y,int* z) { WRITE_ONCE(*y,2); smp_mb(); smp_store_release(z,1); } P2(int* x,int* z) { int r0 = smp_load_acquire(z); smp_store_release(x,1); } Observed y=2; x=2; 2:r0=1;
C11 equivalent:
C Z6.1+fencembonceonce+fencemboncerelease+poacquirerelease Hash=b345ce574bc1ebec7ef82c799f6e5a3d Cycle=PodRWAcquireRelease WseReleaseOnce FenceMbdWWOnceOnce WseOnceOnce FenceMbdWWOnceRelease RfeReleaseAcquire Relax=RfeReleaseAcquire WseReleaseOnce Safe=FenceMbdWW PodRWAcquireRelease WseOnceOnce Generator=diy7 (version 7.46+3) Prefetch=0:x=F,0:y=W,1:y=F,1:z=W,2:z=F,2:x=W Com=Ws Rf Ws Orig=FenceMbdWWOnceOnce WseOnceOnce FenceMbdWWOnceRelease RfeReleaseAcquire PodRWAcquireRelease WseReleaseOnce {} P0(atomic_int* x,atomic_int* y) { atomic_store_explicit(x,2,memory_order_relaxed); 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_relaxed); atomic_thread_fence(memory_order_seq_cst); atomic_store_explicit(z,1,memory_order_release); } P2(atomic_int* x,atomic_int* z) { int r0 = atomic_load_explicit(z,memory_order_acquire); atomic_store_explicit(x,1,memory_order_release); } exists (x=2 /\ y=2 /\ 2:r0=1)