extern void abort(void);
void assume_abort_if_not(int cond) {
  if(!cond) {abort();}
}
extern void abort(void);
#include <assert.h>
void reach_error() { assert(0); }

#include <pthread.h>

#define assume(e) assume_abort_if_not(e)
#undef assert
#define assert(e) { if(!(e)) { ERROR: {reach_error();abort();}(void)0; } }

int x=1, m=0;

void __VERIFIER_atomic_acquire()
{
	assume(m==0);
	m = 1;
}

void __VERIFIER_atomic_release()
{
	assume(m==1);
	m = 0;
}

void* thr1(void* arg) {
  __VERIFIER_atomic_acquire(); // m=0 /\ m'=1
  x = 0;
  x = 1;
  assert(x>=1);
  __VERIFIER_atomic_release();

  return 0;
}

int main()
{
  pthread_t t;

  while(1) pthread_create(&t, 0, thr1, 0);
}