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111
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1 /* { dg-do run } */
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2 /* { dg-options "-O2" } */
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3
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4 void abort ();
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5
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6 typedef struct _Node
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7 {
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8 struct _Node *next, *prev;
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9 } Node;
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10
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11 void __attribute__ ((noinline)) append (Node * q, Node * p)
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12 {
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13 p->next = q;
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14 p->prev = q;
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15 q->next = p;
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16 q->prev = p;
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17 }
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18
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19 inline void
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20 swap (Node ** a, Node ** b)
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21 {
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22 Node *tmp = *a;
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23 *a = *b;
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24 *b = tmp;
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25 }
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26
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27 /* Miscompilation seems to happen here. If one removes the if condition
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28 (which should be true) the program works fine. */
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29 void
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30 ListSwap (Node * x, Node * y)
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31 {
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32 Node *tmp;
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33 if (x->next)
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34 {
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35 swap (&x->next, &y->next);
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36 swap (&x->prev, &y->prev);
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37 x->next->prev = x->prev->next = x;
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38 y->next->prev = y->prev->next = y;
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39 }
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40 }
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41
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42 int
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43 main ()
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44 {
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45 Node A, A1, B, B1;
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46
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47 append (&A, &A1);
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48 append (&B, &B1);
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49
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50 ListSwap (&A, &B);
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51
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52 if (&A != A.next->prev)
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53 abort ();
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54
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55 return 0;
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56 }
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