1  /* { dg-do run { target { stdint_types } } } */
       2  
       3  #include <stdint.h>
       4  #include <stdlib.h>
       5  
       6  void f(uint64_t *a, uint64_t aa) __attribute__((noinline));
       7  void f(uint64_t *a, uint64_t aa)
       8  {
       9    uint64_t new_value = aa;
      10    uint64_t old_value = *a;
      11    int bit_size = 32;
      12      uint64_t mask = (uint64_t)(unsigned)(-1);
      13      uint64_t tmp = old_value & mask;
      14      new_value &= mask;
      15      /* On overflow we need to add 1 in the upper bits */
      16      if (tmp > new_value)
      17          new_value += 1ull<<bit_size;
      18      /* Add in the upper bits from the old value */
      19      new_value += old_value & ~mask;
      20      *a = new_value;
      21  }
      22  int main(void)
      23  {
      24    uint64_t value, new_value, old_value;
      25    value = 0x100000001;
      26    old_value = value;
      27    new_value = (value+1)&(uint64_t)(unsigned)(-1);
      28    f(&value, new_value);
      29    if (value != old_value+1)
      30      __builtin_abort ();
      31    return 0;
      32  }