Bug path

test_4a
‘test_4a’: events 1-2
76 node_b.ptr = malloc (sizeof (int));
^~~~~~~~~~~~~~~~~~~~~
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(1) this call could return NULL
77 global_ptr = &node_a;
78 *node_b.ptr = 42; /* { dg-warning "possibly-NULL" "possibly-NULL" } */
~~~~~~~~~~~~~~~~
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(2) ‘<unknown>’ could be NULL: unchecked value from (1)