C Z6.3+fencembonceonce+fencewmbonceonce+fencembonceacquire Hash=938057edb65418e8f02475f6350c94d4 Cycle=FreAcquireOnce FenceMbdWWOnceOnce WseOnceOnce FenceWmbdWWOnceOnce RfeOnceOnce FenceMbdRROnceAcquire Relax=FreAcquireOnce Safe=FenceMbdWW FenceMbdRR FenceWmbdWW RfeOnceOnce 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=T Com=Ws Rf Fr Orig=FenceMbdWWOnceOnce WseOnceOnce FenceWmbdWWOnceOnce RfeOnceOnce FenceMbdRROnceAcquire FreAcquireOnce {} P0(int* x,int* y) { WRITE_ONCE(*x,1); smp_mb(); WRITE_ONCE(*y,1); } P1(int* y,int* z) { WRITE_ONCE(*y,2); smp_wmb(); WRITE_ONCE(*z,1); } P2(int* x,int* z) { int r0 = READ_ONCE(*z); smp_mb(); int r1 = smp_load_acquire(x); } Observed y=2; 2:r1=0; 2:r0=1;
C11 equivalent:
C Z6.3+fencembonceonce+fencewmbonceonce+fencembonceacquire Hash=938057edb65418e8f02475f6350c94d4 Cycle=FreAcquireOnce FenceMbdWWOnceOnce WseOnceOnce FenceWmbdWWOnceOnce RfeOnceOnce FenceMbdRROnceAcquire Relax=FreAcquireOnce Safe=FenceMbdWW FenceMbdRR FenceWmbdWW RfeOnceOnce 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=T Com=Ws Rf Fr Orig=FenceMbdWWOnceOnce WseOnceOnce FenceWmbdWWOnceOnce RfeOnceOnce FenceMbdRROnceAcquire FreAcquireOnce {} P0(atomic_int* x,atomic_int* y) { atomic_store_explicit(x,1,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_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_relaxed); atomic_thread_fence(memory_order_seq_cst); int r1 = atomic_load_explicit(x,memory_order_acquire); } exists (y=2 /\ 2:r0=1 /\ 2:r1=0)