Re: Bug report gcc 4.8

[Paul Richard Thomas <paul dot richard dot thomas at gmail dot com>]

Dear Walter,

We are putting such effort as we can into the array descriptor reform.
This has to happen for a variety of reasons, including fixing the
likes of Dr Brown's testscase. We have made enormous strides in this
area. Most particularly, the branch devoted to this work, fortran-dev,
now functions like 4.10/4.9 up to a couple of missed vectorization
opportunities in the testsuite. We are aiming to merge 4.10 and this
development branch as soon as possible, so that the API changes occur
early in the release cycle. Just today, we have had some email
exchanges on the mailing list where we summarise what is to be done
and, I hope, we will fix who does what to get to the point of a merge
asap.

With best regards

Paul

On 9 June 2014 17:43, W Spector <w6ws@earthlink.net> wrote:
> Unfortunately Dr Browns recent thread got off on a wrong track, but the
> problem remains.  I am still not convinced that this ICE requires a change
> to the array descriptors.
>
> Here is a slightly changed version of his test case.  I introduced a
> temporary pointer called temp_p.  Then split his pointer assignment into two
> pointer assignments - using temp_p between them.
>
> Either of the two pointer assignments compiles fine.  However together, they
> fail.  While the first pointer assignment could potentially have a stride,
> the second should be a simple copy of the descriptor from one pointer to the
> other.
>
> I should add that the compiler traceback for this case is different than the
> traceback from the code in comment #5 of PR 34640.  In this case, the ICE
> comes from line 1473 of trans-decl.c.  In PR 34640, the ICE comes from line
> 6715 of trans-expr.c.
>
> So it seems to me like a different bug than PR 34640.
>
> Walter
>
> program test_pointers
>   implicit none
>
>   integer :: i, ndata
>
>   ! Note that we make an array of the user defined type,
>   ! not the data component
>
>   type data_t
>      real :: x
>   end type data_t
>
>   type(data_t), allocatable, target :: data(:)
>
>   ! Now define a type containing an 'embedded' data pointer
>
>   type data_pointer_t
>      real, pointer :: p_x(:)
>   end type data_pointer_t
>   type(data_pointer_t) :: data_pointer
>
>   real, pointer :: temp_p(:)
>
>   ndata = 10
>   allocate(data(ndata))
>
>   forall(i=1:ndata) data(i)%x = float(i)
>
> ! Point to the data using the 'embedded' pointer
>
> #if !defined (ORIGINAL)
> ! ICE when both lines are compiled.  Compiles OK when either line is
> ! commented out.
>   temp_p => data%x           ! Potential strided access
>   data_pointer%p_x => temp_p ! Should be a simple copy of the descriptor
> #else
> ! Gregs original code
>   data_pointer%p_x => data%x  ! ICE happens here with gfortran
> #endif
>
>   write(*,*) data_pointer%p_x
>
> end program test_pointers
>
> wws@w6ws-4:~/fortran/gcb$ /usr/local/gcc-trunk/bin/gfortran --version
> GNU Fortran (GCC) 4.10.0 20140524 (experimental)
> Copyright (C) 2014 Free Software Foundation, Inc.
>
> GNU Fortran comes with NO WARRANTY, to the extent permitted by law.
> You may redistribute copies of GNU Fortran
> under the terms of the GNU General Public License.
> For more information about these matters, see the file named COPYING
>
> wws@w6ws-4:~/fortran/gcb$ /usr/local/gcc-trunk/bin/gfortran
> test_pointers.F90
> test_pointers.F90: In function âtest_pointersâ:
> test_pointers.F90:1:0: internal compiler error: Segmentation fault
>  program test_pointers
>  ^
> 0xa36fbf crash_signal
>         ../../gcc-trunk/gcc/toplev.c:337
> 0x626bdb gfc_get_symbol_decl(gfc_symbol*)
>         ../../gcc-trunk/gcc/fortran/trans-decl.c:1473
> 0x62999f generate_local_decl
>         ../../gcc-trunk/gcc/fortran/trans-decl.c:4845
> 0x5e9ef3 do_traverse_symtree
>         ../../gcc-trunk/gcc/fortran/symbol.c:3576
> 0x62a7ba generate_local_vars
>         ../../gcc-trunk/gcc/fortran/trans-decl.c:5017
> 0x62a7ba gfc_generate_function_code(gfc_namespace*)
>         ../../gcc-trunk/gcc/fortran/trans-decl.c:5537
> 0x5be2e8 translate_all_program_units
>         ../../gcc-trunk/gcc/fortran/parse.c:4601
> 0x5be2e8 gfc_parse_file()
>         ../../gcc-trunk/gcc/fortran/parse.c:4798
> 0x5fbc05 gfc_be_parse_file
>         ../../gcc-trunk/gcc/fortran/f95-lang.c:188
> Please submit a full bug report,
> with preprocessed source if appropriate.
> Please include the complete backtrace with any bug report.
> See <http://gcc.gnu.org/bugs.html> for instructions.
> wws@w6ws-4:~/fortran/gcb$
> wws@w6ws-4:~/fortran/gcb$ gfortran pr34640.f90
> pr34640.f90: In function âget_valuesâ:
> pr34640.f90:11:0: internal compiler error: Segmentation fault
>      values => d(:)%value
>  ^
> Please submit a full bug report,
> with preprocessed source if appropriate.
> See <file:///usr/share/doc/gcc-4.8/README.Bugs> for instructions.
> wws@w6ws-4:~/fortran/gcb$
>
> File pr34640 is the code from comment #5 in PR34640
>
> wws@w6ws-4:~/fortran/gcb$ /usr/local/gcc-trunk/bin/gfortran pr34640.f90
> pr34640.f90: In function âget_valuesâ:
> pr34640.f90:11:0: internal compiler error: Segmentation fault
>      values => d(:)%value
>  ^
> 0xa36fbf crash_signal
>         ../../gcc-trunk/gcc/toplev.c:337
> 0x63e330 gfc_trans_pointer_assignment(gfc_expr*, gfc_expr*)
>         ../../gcc-trunk/gcc/fortran/trans-expr.c:6715
> 0x60095a trans_code
>         ../../gcc-trunk/gcc/fortran/trans.c:1656
> 0x62aa8e gfc_generate_function_code(gfc_namespace*)
>         ../../gcc-trunk/gcc/fortran/trans-decl.c:5595
> 0x6021b1 gfc_generate_module_code(gfc_namespace*)
>         ../../gcc-trunk/gcc/fortran/trans.c:1978
> 0x5be001 translate_all_program_units
>         ../../gcc-trunk/gcc/fortran/parse.c:4588
> 0x5be001 gfc_parse_file()
>         ../../gcc-trunk/gcc/fortran/parse.c:4798
> 0x5fbc05 gfc_be_parse_file
>         ../../gcc-trunk/gcc/fortran/f95-lang.c:188
> Please submit a full bug report,
> with preprocessed source if appropriate.
> Please include the complete backtrace with any bug report.
> See <http://gcc.gnu.org/bugs.html> for instructions.
> wws@w6ws-4:~/fortran/gcb$



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