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// from SV-COMP, based on code found in the Linux kernel
#include <stdlib.h>
struct list_head {
struct list_head *next, *prev;
};
struct node {
int value;
struct list_head linkage;
struct list_head nested;
};
struct list_head gl_list = { &gl_list, &gl_list };
int main()
{
_Bool maybe_dynamic;
struct node X;
struct node *N = maybe_dynamic ? malloc(sizeof(struct node)) : &X;
if (!N)
return 1;
N->value = 42;
gl_list.prev=&N->linkage;
N->linkage.next=&gl_list;
N->linkage.prev=&gl_list;
gl_list.next=&N->linkage;
// we have:
// gl_list.prev=&D->linkage;
// D->linkage.next=&gl_list
// D->linkage.prev=&gl_list;
// gl_list.next=&D->linkage;
N->nested.next = &(N->nested);
N->nested.prev = &(N->nested);
const struct list_head *head=&gl_list;
// go one step backward
head = head->prev;
// we have:
// head=&D->linkage
// resolve root
const struct node *node =
(struct node *) ((char *)(head) -
(unsigned long)(&((struct node *)0)->linkage));
// we have:
// node=&D (==&D->value)
__CPROVER_assert(node == N, "");
__CPROVER_assert(head == N->linkage.next->prev, "");
__CPROVER_assert(head == N->linkage.prev->next, "");
__CPROVER_assert(head == node->linkage.next->prev, "");
__CPROVER_assert(head == node->linkage.prev->next, "");
return 0;
}
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