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From: "james.s.spencer at gmail dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug fortran/59781] New: Incorrect initialisation of derived type Date: Sun, 12 Jan 2014 21:26:00 -0000 [thread overview] Message-ID: <bug-59781-4@http.gcc.gnu.org/bugzilla/> (raw) http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59781 Bug ID: 59781 Summary: Incorrect initialisation of derived type Product: gcc Version: 4.8.2 Status: UNCONFIRMED Severity: normal Priority: P3 Component: fortran Assignee: unassigned at gcc dot gnu.org Reporter: james.s.spencer at gmail dot com Created attachment 31818 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=31818&action=edit Tarball containing example code, tree produced by gfortran 4.8.2 and Makefile. (Complete modules and a makefile is attached. Also confirmed against 4.6.3) With the definition type dSFMT_t private type(c_ptr) :: dSFMT_state = c_null_ptr real(c_double), allocatable :: random_store(:) end type dSFMT_t the dSFMT_t objects in the following module should both be initialised with a null pointer for the dSFMT_state component: module hilbert_space implicit none contains subroutine test_rng() use dSFMT_interface type(dSFMT_t) :: rng call dSFMT_init(7, 50000, rng) end subroutine test_rng subroutine estimate_hilbert_space() use dSFMT_interface type(dSFMT_t) :: rng call dSFMT_init(7, 50000, rng) end subroutine estimate_hilbert_space end module hilbert_space Instead only the rng object in estimate_hilbert_space is correctly initialised. The relevant parts of the tree are: estimate_hilbert_space () { struct dsfmt_t rng; try { { struct dsfmt_t dsfmt_t.0; dsfmt_t.0.dsfmt_state = 0B; dsfmt_t.0.random_store.data = 0B; rng = dsfmt_t.0; } [...] } } test_rng () { struct dsfmt_t rng; try { rng.random_store.data = 0B; [...] } } This bug is tricky to observe---small changes to the code (e.g. making rng a pointer, code reorganisation, having additional or fewer procedures in the same file, removing the random_store allocatable component etc. can lead to the dSFMT_t objects being correctly initialised. I had the above code (with additions) in a large code base for several months until an innocuous refactoring revealed it. See also discussion at https://groups.google.com/forum/#!topic/comp.lang.fortran/WogpvhUny4c, where Janus posted a smaller example which breaks under gfortran trunk.
next reply other threads:[~2014-01-12 21:26 UTC|newest] Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top 2014-01-12 21:26 james.s.spencer at gmail dot com [this message] 2014-01-12 21:41 ` [Bug fortran/59781] [4.9 Regression] [F03] " janus at gcc dot gnu.org 2014-01-12 21:56 ` janus at gcc dot gnu.org 2014-01-13 8:38 ` [Bug fortran/59781] [4.7/4.8/4.9 " janus at gcc dot gnu.org 2014-01-13 8:56 ` dominiq at lps dot ens.fr 2014-01-13 9:18 ` jakub at gcc dot gnu.org 2014-01-13 15:49 ` janus at gcc dot gnu.org 2014-01-13 19:58 ` janus at gcc dot gnu.org 2014-04-22 11:38 ` [Bug fortran/59781] [4.7/4.8/4.9/4.10 " jakub at gcc dot gnu.org 2014-07-16 13:30 ` [Bug fortran/59781] [4.8/4.9/4.10 " jakub at gcc dot gnu.org 2014-10-30 10:42 ` [Bug fortran/59781] [4.8/4.9/5 " jakub at gcc dot gnu.org 2015-06-26 19:56 ` [Bug fortran/59781] [4.9/5/6 " jakub at gcc dot gnu.org 2015-06-26 20:28 ` jakub at gcc dot gnu.org
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