[mjevans]

Finding 'the hack' to get the compilers to behave is one of the areas where I'd like to see better warnings (which could get promoted to errors).

  while (node) {
    value += node->value;
    next = node->next;
    node++;  // Line 101
    if (node != next) {
      node = next;
    }
  }
  // Compiler warning
  // Warning: Lines 101 102 103: always true evaluation combined

The pivot here is moving the fallback out of the tight inner loop, this also introduces a new statement block. The additional loop exit condition is dependent on values in memory and cannot be optimized out; since it's now directing flow control directly instead of always assuring the value of node becomes node->next (an indirect method of flow control).

  while (node) {
    while (node) {
      value += node->value;
      if (node + 1 != node->next) break;
      node++;
    }
    node = node->next;
  }