[Bug fortran/92208] New: internal compile error, character array of dynamic length returned from function and passed to subroutine

[nils.reiche at dlr dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92208

            Bug ID: 92208
           Summary: internal compile error, character array of dynamic
                    length returned from function and passed to subroutine
           Product: gcc
           Version: 9.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: nils.reiche at dlr dot de
  Target Milestone: ---

Description:
A function creates and return an array of characters of a certain length that
is allocated at the call of the function. When the returned array is not passed
to any other function, the code compiles and runs perfectly. But passing this
character array to another subroutine causes an internal compiler error.
Attached is the source code of the test program. It has been working for
compiler versions gcc-5.2 and gcc-8.2, others were not tested.



Source code:

program stringtest

  implicit none
  integer, parameter :: noVars = 2

  print*, "varNames: ", createVarnames("var",noVars)
  call function1(noVars,createVarnames("var",noVars),"path")

contains

function createVarnames(string,noVars) result(stringArray)
  implicit none
  character(len=*),                        intent(in)  :: string
  integer,                                 intent(in)  :: noVars
  character(len=len_trim(string)+6), dimension(noVars) :: stringArray
  integer :: i
  do i=1,noVars
    write(stringArray(i),'(a,i0)') string, i
  enddo
end function createVarnames

subroutine function1(noVars,varNames,path)
  implicit none
  integer, intent(in)  :: noVars
  character(len=*), intent(in)  :: path
  character(len=*), dimension(noVars) :: varNames

  print*, "function1-path    : ", trim(path)
  print*, "function1-varNames: ", varNames

end subroutine function1

end program stringtest


Compiler specifications:

gfortran -v
Using built-in specs.
COLLECT_GCC=gfortran
COLLECT_LTO_WRAPPER=/home_as/ta/moes_mc/software_rhel7/compilers/gcc-9.2.0-install/libexec/gcc/x86_64-pc-linux-gnu/9.2.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc-9.2.0/configure
--prefix=/home_as/ta/moes_mc/software_rhel7/compilers/gcc-9.2.0-install
--enable-threads
Thread model: posix
gcc version 9.2.0 (GCC)



Compiler error message:

gfortran -Wall -Wextra string_test.F90
string_test.F90:1:0:

    1 | program stringtest
      |
internal compiler error: ..__result from createvarnames referenced in
stringtest
0xbbac19 convert_nonlocal_reference_op
        ../../gcc-9.2.0/gcc/tree-nested.c:1053
0xd84882 walk_tree_1(tree_node**, tree_node* (*)(tree_node**, int*, void*),
void*, hash_set<tree_node*, false, default_hash_traits<tree_node*> >*,
tree_node* (*)(tree_node**, int*, tree_node* (*)(tree_node**, int*, void*),
void*, hash_set<tree_node*, false, default_hash_traits<tree_node*> >*))
        ../../gcc-9.2.0/gcc/tree.c:12151
0x909619 walk_gimple_op(gimple*, tree_node* (*)(tree_node**, int*, void*),
walk_stmt_info*)
        ../../gcc-9.2.0/gcc/gimple-walk.c:253
0x9099f1 walk_gimple_stmt(gimple_stmt_iterator*, tree_node*
(*)(gimple_stmt_iterator*, bool*, walk_stmt_info*), tree_node* (*)(tree_node**,
int*, void*), walk_stmt_info*)
        ../../gcc-9.2.0/gcc/gimple-walk.c:586
0x909b30 walk_gimple_seq_mod(gimple**, tree_node* (*)(gimple_stmt_iterator*,
bool*, walk_stmt_info*), tree_node* (*)(tree_node**, int*, void*),
walk_stmt_info*)
        ../../gcc-9.2.0/gcc/gimple-walk.c:51
0x909ab1 walk_gimple_stmt(gimple_stmt_iterator*, tree_node*
(*)(gimple_stmt_iterator*, bool*, walk_stmt_info*), tree_node* (*)(tree_node**,
int*, void*), walk_stmt_info*)
        ../../gcc-9.2.0/gcc/gimple-walk.c:631
0x909b30 walk_gimple_seq_mod(gimple**, tree_node* (*)(gimple_stmt_iterator*,
bool*, walk_stmt_info*), tree_node* (*)(tree_node**, int*, void*),
walk_stmt_info*)
        ../../gcc-9.2.0/gcc/gimple-walk.c:51
0x909a71 walk_gimple_stmt(gimple_stmt_iterator*, tree_node*
(*)(gimple_stmt_iterator*, bool*, walk_stmt_info*), tree_node* (*)(tree_node**,
int*, void*), walk_stmt_info*)
        ../../gcc-9.2.0/gcc/gimple-walk.c:675
0x909b30 walk_gimple_seq_mod(gimple**, tree_node* (*)(gimple_stmt_iterator*,
bool*, walk_stmt_info*), tree_node* (*)(tree_node**, int*, void*),
walk_stmt_info*)
        ../../gcc-9.2.0/gcc/gimple-walk.c:51
0x909a71 walk_gimple_stmt(gimple_stmt_iterator*, tree_node*
(*)(gimple_stmt_iterator*, bool*, walk_stmt_info*), tree_node* (*)(tree_node**,
int*, void*), walk_stmt_info*)
        ../../gcc-9.2.0/gcc/gimple-walk.c:675
0x909b30 walk_gimple_seq_mod(gimple**, tree_node* (*)(gimple_stmt_iterator*,
bool*, walk_stmt_info*), tree_node* (*)(tree_node**, int*, void*),
walk_stmt_info*)
        ../../gcc-9.2.0/gcc/gimple-walk.c:51
0xbb8708 walk_body
        ../../gcc-9.2.0/gcc/tree-nested.c:703
0xbb8ee0 walk_function
        ../../gcc-9.2.0/gcc/tree-nested.c:714
0xbb8ee0 walk_all_functions
        ../../gcc-9.2.0/gcc/tree-nested.c:779
0xbbbe0c lower_nested_functions(tree_node*)
        ../../gcc-9.2.0/gcc/tree-nested.c:3507
0x7cae9c cgraph_node::analyze()
        ../../gcc-9.2.0/gcc/cgraphunit.c:673
0x7cd4d7 analyze_functions
        ../../gcc-9.2.0/gcc/cgraphunit.c:1126
0x7ce0c2 symbol_table::finalize_compilation_unit()
        ../../gcc-9.2.0/gcc/cgraphunit.c:2837
Please submit a full bug report,