[Bug fortran/83149] New: ICE on SELECT CASE: crash_signal in toplev.c:325

[neil.n.carlson at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83149

            Bug ID: 83149
           Summary: ICE on SELECT CASE: crash_signal in toplev.c:325
           Product: gcc
           Version: 8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: neil.n.carlson at gmail dot com
  Target Milestone: ---

The current 8.0 trunk gives an ICE on the following example, but only when then
the program units are in two separate files. Works fine with 7.2.1 and 6.4.1.

module mod
  character(8) string
contains
  function get_string() result(s)
    character(len_trim(string)) s
    s = string
  end function
end module

use mod
string = 'fubar'
select case (get_string())
case default
end select
end

Here's the traceback:

$ gfortran gfortran-20171124e.f90 gfortran-20171124e-main.f90 
gfortran-20171124e-main.f90:3:0:

 select case (get_string())

internal compiler error: Segmentation fault
0xd6b98f crash_signal
        ../../gcc/toplev.c:325
0x96852e gfc_sym_type(gfc_symbol*)
        ../../gcc/fortran/trans-types.c:2207
0x968ab7 gfc_get_function_type(gfc_symbol*)
        ../../gcc/fortran/trans-types.c:2969
0x907aed gfc_get_extern_function_decl(gfc_symbol*)
        ../../gcc/fortran/trans-decl.c:2126
0x907ffd gfc_get_extern_function_decl(gfc_symbol*)
        ../../gcc/fortran/trans-decl.c:1974
0x91bb24 conv_function_val
        ../../gcc/fortran/trans-expr.c:3722
0x91bb24 gfc_conv_procedure_call(gfc_se*, gfc_symbol*, gfc_actual_arglist*,
gfc_expr*, vec<tree_node*, va_gc, vl_embed>*)
        ../../gcc/fortran/trans-expr.c:6142
0x91c6fa gfc_conv_expr(gfc_se*, gfc_expr*)
        ../../gcc/fortran/trans-expr.c:7852
0x923a6a gfc_conv_expr_reference(gfc_se*, gfc_expr*)
        ../../gcc/fortran/trans-expr.c:7952
0x957611 gfc_trans_character_select
        ../../gcc/fortran/trans-stmt.c:2819
0x95ee1c gfc_trans_select(gfc_code*)
        ../../gcc/fortran/trans-stmt.c:3158
0x8e48b7 trans_code
        ../../gcc/fortran/trans.c:1940
0x90e7a8 gfc_generate_function_code(gfc_namespace*)
        ../../gcc/fortran/trans-decl.c:6437
0x89d036 translate_all_program_units
        ../../gcc/fortran/parse.c:6091
0x89d036 gfc_parse_file()
        ../../gcc/fortran/parse.c:6294
0x8e0eaf gfc_be_parse_file
        ../../gcc/fortran/f95-lang.c:204