int __unbuffered_cnt=0; int __unbuffered_p0_r1=0; int __unbuffered_p0_r3=0; int __unbuffered_p1_r1=0; int __unbuffered_p1_r3=0; int x=0; int y=0; void * P0(void * arg) { __unbuffered_p0_r1 = 1; y = __unbuffered_p0_r1; __unbuffered_p0_r3 = 1; x = __unbuffered_p0_r3; // Instrumentation for CPROVER fence; __unbuffered_cnt++; } void * P1(void * arg) { __unbuffered_p1_r1 = x; __unbuffered_p1_r3 = y; // Instrumentation for CPROVER fence; __unbuffered_cnt++; } int main() { __CPROVER_ASYNC_0: P0(0); __CPROVER_ASYNC_1: P1(0); __CPROVER_assume(__unbuffered_cnt==2); __CPROVER_assert(!(__unbuffered_p1_r1==1 && __unbuffered_p1_r3==0), "Program proven to be relaxed for PPC, model checker says YES."); return 0; }