Bug 36132

testcase:

MODULE M1
  INTEGER, PARAMETER :: dp=KIND(0.0D0)
CONTAINS
  SUBROUTINE S1(a)
         REAL(dp), DIMENSION(45), INTENT(OUT), &
      OPTIONAL                               :: a
      IF (PRESENT(a)) a=0.0_dp
  END SUBROUTINE S1
  SUBROUTINE S2(a)
          REAL(dp), DIMENSION(:, :), INTENT(OUT), &
      OPTIONAL                               :: a
      CALL S1(a)
  END SUBROUTINE
END MODULE M1
USE M1
REAL(dp) :: a(5,9)
CALL S2()
END

I have probably a too old gfortran 4.4.0 (namely 20080424), but it does not crash here. I see the same valgrind output using gfortran 4.1, 4.2, 4.3 and 4.4.

right, it is actually new CP2K code since I checked 4.3. No regression thus.

The problem isn't specific to in_pack, it's the
fact that we don't initialize the array descriptor
correctly.

s2 shows

  if (a != 0B)
    {
      {
        integer(kind=4) D.638;

        D.638 = a->dim[0].stride;
        stride.1 = D.638 != 0 ? D.638 : 1;
   
        ...
      }
    }
so we set stride.1 only if a is present.  So far, so good.

Later, unconditionally, we have

    struct array2_real(kind=8) parm.6;

...

    D.633 = stride.1;
    parm.6.dim[0].lbound = 1;
    parm.6.dim[0].ubound = ubound.0;
    parm.6.dim[0].stride = NON_LVALUE_EXPR <D.633>;
    parm.6.data = (void *) &(*a.0)[0];
    parm.6.offset = NON_LVALUE_EXPR <D.632>;
    D.635 = _gfortran_internal_pack (&parm.6);

We need to call _gfortran_internal_pack on optional arguments
only when the optional arguments are present.

Setting subject.

this seems one of the few wrong-code bugs that affects Fortran95 in a system independent way. Any chance to fix this, with a backport to 4.3(.2) ? I believe we could try to code around it for new versions of CP2K, but that would just be CP2K. I would guess that the fix is very localized and 'obvious'.

(In reply to comment #5)
> this seems one of the few wrong-code bugs that affects Fortran95 in a system
> independent way. Any chance to fix this, with a backport to 4.3(.2) ? I believe
> we could try to code around it for new versions of CP2K, but that would just be
> CP2K. I would guess that the fix is very localized and 'obvious'.

This is not a regression, but I guess as you that the fix should be simple, so why not? I'll look into it.

This is an important bug indeed, and I'm swamped with work, so I'd better leave it to someone else.

Pointer for myself (or someone else): Should be added in trans-array.c's gfc_conv_array_parameter and maybe also gfc_trans_dummy_array_bias.

Any plans to look into a fix for this for 4.3.X ?  This is variant of the testcase that causes a runtime abort (trunk on x86_64-unknown-linux-gnu):

> gfortran -O2 test.f90 ; ./a.out
Operating system error: Cannot allocate memory
Memory allocation failed

> cat test.f90
MODULE M1
  INTEGER, PARAMETER :: dp=KIND(0.0D0)
CONTAINS
  SUBROUTINE S0()
    REAL(dp) :: a(5,9,3,5)
    CALL S1(a)
  END SUBROUTINE
  SUBROUTINE S1(a)
         REAL(dp), DIMENSION(45), INTENT(OUT), &
      OPTIONAL                               :: a
      IF (PRESENT(a)) CALL RANDOM_NUMBER(a)
  END SUBROUTINE S1
  SUBROUTINE S2(a)
          REAL(dp), DIMENSION(:, :), INTENT(OUT), &
      OPTIONAL                               :: a
      CALL S1(a)
  END SUBROUTINE
END MODULE M1
USE M1

CALL S0()
CALL S2()
END

Subject: Bug 36132

Author: burnus
Date: Sun Jul 27 10:45:44 2008
New Revision: 138186

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=138186
Log:
2008-07-27  Tobias Burnus  <burnus@net-b.de>

        PR fortran/36132
        PR fortran/29952
        PR fortran/36909
        * trans.c (gfc_trans_runtime_check): Allow run-time warning
        * besides
        run-time error.
        * trans.h (gfc_trans_runtime_check): Update declaration.
        * trans-array.c
        * (gfc_trans_array_ctor_element,gfc_trans_array_bound_check,
        gfc_conv_array_ref,gfc_conv_ss_startstride,gfc_trans_dummy_array_bias):
        Updated gfc_trans_runtime_check calls.
        (gfc_conv_array_parameter): Implement flag_check_array_temporaries,
        fix packing/unpacking for nonpresent optional actuals to optional
        formals.
        * trans-array.h (gfc_conv_array_parameter): Update declaration.
        * trans-expr.c (gfc_conv_substring,gfc_trans_arrayfunc_assign,
        gfc_conv_function_call): Updated gfc_trans_runtime_check calls.
        (gfc_conv_function_call): Update gfc_conv_array_parameter calls.
        * trans-expr.c (gfc_trans_goto): Updated gfc_trans_runtime_check
        calls.
        * trans-io.c (set_string,gfc_conv_intrinsic_repeat): Ditto.
        (gfc_conv_intrinsic_transfer,gfc_conv_intrinsic_loc): Same for
        gfc_conv_array_parameter.
        * trans-intrinsics.c (gfc_conv_intrinsic_bound): Ditto.
        * trans-decl.c (gfc_build_builtin_function_decls): Add
        gfor_fndecl_runtime_warning_at.
        * lang.opt: New option fcheck-array-temporaries.
        * gfortran.h (gfc_options): New flag_check_array_temporaries.
        * options.c (gfc_init_options, gfc_handle_option): Handle flag.
        * invoke.texi: New option fcheck-array-temporaries.

2008-07-27  Tobias Burnus  <burnus@net-b.de>

        PR fortran/36132
        PR fortran/29952
        PR fortran/36909
        * runtime/error.c: New function runtime_error_at.
        * gfortran.map: Ditto.
        * libgfortran.h: Ditto.

2008-07-27  Tobias Burnus  <burnus@net-b.de>

        PR fortran/36132
        PR fortran/29952
        PR fortran/36909
        gfortran.dg/internal_pack_4.f90: New.
        gfortran.dg/internal_pack_5.f90: New.
        gfortran.dg/array_temporaries_2.f90: New.


Added:
    trunk/gcc/testsuite/gfortran.dg/array_temporaries_2.f90
    trunk/gcc/testsuite/gfortran.dg/internal_pack_4.f90
    trunk/gcc/testsuite/gfortran.dg/internal_pack_5.f90
Modified:
    trunk/gcc/fortran/ChangeLog
    trunk/gcc/fortran/gfortran.h
    trunk/gcc/fortran/invoke.texi
    trunk/gcc/fortran/lang.opt
    trunk/gcc/fortran/options.c
    trunk/gcc/fortran/trans-array.c
    trunk/gcc/fortran/trans-array.h
    trunk/gcc/fortran/trans-decl.c
    trunk/gcc/fortran/trans-expr.c
    trunk/gcc/fortran/trans-intrinsic.c
    trunk/gcc/fortran/trans-io.c
    trunk/gcc/fortran/trans-stmt.c
    trunk/gcc/fortran/trans.c
    trunk/gcc/fortran/trans.h
    trunk/gcc/testsuite/ChangeLog
    trunk/libgfortran/ChangeLog
    trunk/libgfortran/gfortran.map
    trunk/libgfortran/libgfortran.h
    trunk/libgfortran/runtime/error.c

Subject: Bug 36132

Author: burnus
Date: Sun Jul 27 11:41:35 2008
New Revision: 138187

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=138187
Log:
2008-07-27  Tobias Burnus  <burnus@net-b.de>

       PR fortran/36132
       * trans-array.c (gfc_conv_array_parameter): Fix packing/unpacking
       for nonpresent optional actuals to optional formals.
       * trans-array.h (gfc_conv_array_parameter): Update declaration.
       * trans-expr.c (gfc_conv_function_call,gfc_trans_arrayfunc_assign):
       Update gfc_conv_array_parameter calls.
       * trans-intrinsics (gfc_conv_intrinsic_transfer,
       gfc_conv_intrinsic_loc): Ditto.

2008-07-27  Tobias Burnus  <burnus@net-b.de>

       PR fortran/36132
       * gfortran.dg/internal_pack_4.f90: New.


Added:
    branches/gcc-4_3-branch/gcc/testsuite/gfortran.dg/internal_pack_4.f90
Modified:
    branches/gcc-4_3-branch/gcc/fortran/ChangeLog
    branches/gcc-4_3-branch/gcc/fortran/trans-array.c
    branches/gcc-4_3-branch/gcc/fortran/trans-array.h
    branches/gcc-4_3-branch/gcc/fortran/trans-expr.c
    branches/gcc-4_3-branch/gcc/fortran/trans-intrinsic.c
    branches/gcc-4_3-branch/gcc/testsuite/ChangeLog

FIXED on the trunk and on the 4.3 branch. Thanks for the bug report.