// This file is part of the SV-Benchmarks collection of verification tasks:
// https://gitlab.com/sosy-lab/benchmarking/sv-benchmarks
//
// SPDX-FileCopyrightText: 2021 F. Schuessele <schuessf@informatik.uni-freiburg.de>
// SPDX-FileCopyrightText: 2021 D. Klumpp <klumpp@informatik.uni-freiburg.de>
//
// SPDX-License-Identifier: LicenseRef-BSD-3-Clause-Attribution-Vandikas

typedef unsigned long int pthread_t;

union pthread_attr_t
{
  char __size[36];
  long int __align;
};
typedef union pthread_attr_t pthread_attr_t;

extern void __assert_fail(const char *__assertion, const char *__file,
      unsigned int __line, const char *__function)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__noreturn__));
void reach_error() { __assert_fail("0", "popl20-three-array-max.wvr.c", 21, __extension__ __PRETTY_FUNCTION__); }
extern int pthread_create (pthread_t *__restrict __newthread,
      const pthread_attr_t *__restrict __attr,
      void *(*__start_routine) (void *),
      void *__restrict __arg) __attribute__ ((__nothrow__)) __attribute__ ((__nonnull__ (1, 3)));
extern int pthread_join (pthread_t __th, void **__thread_return);

typedef unsigned int size_t;
extern void *malloc (size_t __size) __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__malloc__)) ;

extern int  __VERIFIER_nondet_int(void);
extern _Bool __VERIFIER_nondet_bool(void);
extern void __VERIFIER_atomic_begin(void);
extern void __VERIFIER_atomic_end(void);

extern void abort(void);
void assume_abort_if_not(int cond) {
  if(!cond) {abort();}
}

int *A, *B, *C;
int maxa, maxb, maxc, N, p;

int *create_fresh_int_array(int size);
int plus(int a, int b);

void* thread1() {
  for (int i=1; i<N; i++) {
    if (maxa <= A[i]) {
      maxa = A[i];
    }
    if (maxb <= B[i]) {
      maxb = B[i];
    }
  }

  return 0;
}

void* thread2() {
  for (int i=1; i<N; i++) {
    __VERIFIER_atomic_begin();
    C[i] = plus(A[i], B[i]);
    p = i + 1;
    __VERIFIER_atomic_end();
  }

  return 0;
}

void* thread3() {
  int i = 1;
  while (i < N) {
    __VERIFIER_atomic_begin();
    _Bool cond = i < p;
    __VERIFIER_atomic_end();
    if (cond) {
      __VERIFIER_atomic_begin();
      if (maxc <= C[i]) {
        maxc = C[i];
      }
      __VERIFIER_atomic_end();
      i++;
    }
  }

  return 0;
}

int main() {
  pthread_t t1, t2, t3;

  N = __VERIFIER_nondet_int();
  assume_abort_if_not(N > 0);
  A = create_fresh_int_array(N);
  B = create_fresh_int_array(N);
  C = create_fresh_int_array(N);
  
  p = 1;
  
  maxa = A[0];
  maxb = B[0];
  maxc = plus(A[0], B[0]);
  
  // main method
  pthread_create(&t1, 0, thread1, 0);
  pthread_create(&t2, 0, thread2, 0);
  pthread_create(&t3, 0, thread3, 0);
  pthread_join(t1, 0);
  pthread_join(t2, 0);
  pthread_join(t3, 0);
  
  assume_abort_if_not(maxc > plus(maxa, maxb));
  reach_error();

  return 0;
}

int *create_fresh_int_array(int size) {
  assume_abort_if_not(size >= 0);
  assume_abort_if_not(size <= (((size_t) 4294967295) / sizeof(int)));

  int* arr = (int*)malloc(sizeof(int) * (size_t)size);
  for (int i = 0; i < size; i++) {
    arr[i] = __VERIFIER_nondet_int();
  }
  return arr;
}

int plus(int a, int b) {
  assume_abort_if_not(b >= 0 || a >= -2147483648 - b);
  assume_abort_if_not(b <= 0 || a <= 2147483647 - b);
  return a + b;
}