gcc/testsuite/gcc.dg/torture/pr67736.c

   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 }