http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58007
--- Comment #2 from Tobias Burnus <burnus at gcc dot gnu.org> --- Created attachment 30567 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=30567&action=edit Reduced test case Reduced test case, which fails at least on my 86-64-gnu-linux system with a recent GCC 4.9. Compile as: $ gfortran matrix.f90 ellpack.f90 bsr.f90 matrix_c.f90 matrix_c.f90:4.8: use bsr 1 Internal Error at (1): free_pi_tree(): Unresolved fixup * * * The triggered assert is: 221 free_pi_tree (pointer_info *p) 222 { 223 if (p == NULL) 224 return; 225 226 if (p->fixup != NULL) 227 gfc_internal_error ("free_pi_tree(): Unresolved fixup"); For the failing case, one has: (gdb) p *p->fixup $4 = {pointer = 0x1678e08, next = 0x16780a0} (gdb) p *p $2 = {priority = 38379, left = 0x1609dd0, right = 0x1606b20, integer = 6, type = P_COMPONENT, fixup = 0x1678f80, u = {pointer = 0x0, rsym = {sym = 0x0, true_name = 0x0, module = 0x0, binding_label = 0x0, stfixup = 0x0, symtree = 0x0, state = UNUSED, ns = 0, referenced = 0, renamed = 0, where = {column = 0, line = 0, pos = 0}}, wsym = {sym = 0x0, state = UNREFERENCED}}} Here, *(p->fixup->pointer) == NULL and *p->fixup->next->pointer == NULL. Debugging shows that p->fixup->pointer is the address of the "cp" argument in the call to mio_pointer_ref in mio_component_ref for sym == __class_bsr_Bsr_matrix and the component name "max_degreemio_pointer_ref". And p->fixup->next->pointer is sym='__class_bsr_Bsr_matrix' and component name max_degreemio_pointer_ref (i.e. the same, except that "cp" has a different pointer address.) * * * read_cleanup takes care of resolve_fixups - but only for p->type == P_SYMBOL. However, we have here a p->type == P_COMPONENT.