[Bug fortran/35810] [TR 15581 / F2003] Automatic reallocation on assignment to allocatable variables

["pault at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35810

--- Comment #11 from Paul Thomas <pault at gcc dot gnu.org> 2010-11-28 13:47:31 UTC ---
Author: pault
Date: Sun Nov 28 13:47:26 2010
New Revision: 167220

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=167220
Log:
2010-11-28  Paul Thomas  <pault@gcc.gnu.org>

     PR fortran/35810
    * trans-array.c (gfc_trans_array_constructor): If the loop->to
    is a VAR_DECL, assume this is dynamic. In this case, use the
    counter to obtain the value and set loop->to appropriately.
    (gfc_conv_ss_descriptor): Always save the offset of a variable
    in info.saved_offset.
    (gfc_conv_ss_startstride): Do not attempt bound checking of the
    lhs of an assignment, if allocatable and f2003 is allowed.
    (gfc_conv_loop_setup): If possible, do not use an allocatable
    lhs variable for the loopspec.
    (gfc_is_reallocatable_lhs): New function.
    (get_std_lbound): New function.
    (gfc_alloc_allocatable_for_assignment): New function.
    * gfortran.h : Add flag_realloc_lhs to the options structure.
    * lang.opt : Add option f(no-)realloc-lhs.
    * invoke.texi : Document option f(no-)realloc-lhs.
    * options.c (gfc_init_options, gfc_post_options,
    gfc_handle_option): Incorporate f(no-)realloc-lhs with default
    to frealloc_lhs for -std > f95.
    * trans-array.h : Add primitive for previous.
    * trans-expr.c (gfc_conv_string_length): Return if character
    length is a variable and the expression is NULL.
    (gfc_conv_procedure_call): If the call is of the kind x = f(...)
    and the lhs is allocatable and reallocation on assignment OK,
    call gfc_alloc_allocatable_for_assignment. Do not generate the
    function call unless direct by reference.
    (realloc_lhs_loop_for_fcn_call): New function.
    (realloc_lhs_bounds_for_intrinsic_call): New function.
    (gfc_trans_arrayfunc_assign): Reallocation assignments need
    a loopinfo and for the loop bounds to be set.  With intrinsic
    functions, free the lhs data and let the library allocate the
    data array. Done by the new functions above.
    (gfc_trans_assignment_1): If the lhs is allocatable and
    reallocation on assignment is allowed, mark the lhs and use
    gfc_alloc_allocatable_for_assignment to make the reallocation.
    * trans.h : Add is_alloc_lhs bitfield to gfc_ss structure.

2010-11-28  Paul Thomas  <pault@gcc.gnu.org

    PR fortran/35810
    * gfortran.dg/realloc_on_assign_1.f03: New test.
    * gfortran.dg/realloc_on_assign_2.f03: New test.
    * gfortran.dg/transpose_2.f90: dg-option -fno-realloc-lhs.
    * gfortran.dg/unpack_bounds_1.f90: The same.
    * gfortran.dg/cshift_bounds_2.f90: The same.
    * gfortran.dg/matmul_bounds_2.f90: The same.
    * gfortran.dg/matmul_bounds_3.f90: The same.
    * gfortran.dg/matmul_bounds_4.f90: The same.
    * gfortran.dg/matmul_bounds_5.f90: The same.

Added:
    trunk/gcc/testsuite/gfortran.dg/realloc_on_assign_1.f03
    trunk/gcc/testsuite/gfortran.dg/realloc_on_assign_2.f03
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-expr.c
    trunk/gcc/fortran/trans-types.c
    trunk/gcc/fortran/trans.h
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/gfortran.dg/cshift_bounds_2.f90
    trunk/gcc/testsuite/gfortran.dg/matmul_bounds_2.f90
    trunk/gcc/testsuite/gfortran.dg/matmul_bounds_3.f90
    trunk/gcc/testsuite/gfortran.dg/matmul_bounds_4.f90
    trunk/gcc/testsuite/gfortran.dg/matmul_bounds_5.f90
    trunk/gcc/testsuite/gfortran.dg/transpose_2.f90
    trunk/gcc/testsuite/gfortran.dg/unpack_bounds_1.f90