[Bug fortran/97927] gfortran: ICE in lookup_field_for_decl, at tree-nested.c:288

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97927

--- Comment #13 from Tobias Burnus <burnus at gcc dot gnu.org> ---
Created attachment 50313
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=50313&action=edit
Reduced testcase - run with 'gfortran file.f90' (seems to require
--enable-checking=yes)

The generated code has:

__attribute__((fn spec (". ")))
void zrho2 ()   // <<--- nested in exxengy
{
  return;
}

__attribute__((fn spec (". ")))
void exxengy ()
{
  static void zrho2 (void);

  ierror = {CLOBBER};
  mpi_allreduce (&ierror);
}


ICE: In tree-nested.c's convert_local_reference_stmt, there is:

2524        case GIMPLE_ASSIGN:
2525          if (gimple_clobber_p (stmt))
2526            {
2527              tree lhs = gimple_assign_lhs (stmt);
2528              if (DECL_P (lhs)
2529                  && !use_pointer_in_frame (lhs)
2530                  && lookup_field_for_decl (info, lhs, NO_INSERT))

with:

(gdb) p debug_gimple_seq(*gsi->seq)
ierror = {CLOBBER};
mpi_allreduce (&ierror);

and lhs == decl in the following:

#0  lookup_field_for_decl (info=0x2f28150, decl=0x7ffff7ffbab0,
insert=NO_INSERT) at ../../repos/gcc/gcc/tree-nested.c:385
385       gcc_checking_assert (decl_function_context (decl) == info->context);

with

(gdb) p debug_tree(info->context)
 <function_decl 0x7ffff7668200 exxengy

and

(gdb) p decl_function_context (decl)
$3 = (tree_node *) 0x0

(gdb) p debug_tree(decl)
 <var_decl 0x7ffff7ffbab0 ierror
    type <integer_type 0x7ffff74a95e8 integer(kind=4) public SI
        size <integer_cst 0x7ffff7494df8 constant 32>
        unit-size <integer_cst 0x7ffff7494e10 constant 4>
        align:32 warn_if_not_align:0 symtab:0 alias-set -1 canonical-type
0x7ffff74a95e8 precision:32 min <integer_cst 0x7ffff7494db0 -2147483648> max
<integer_cst 0x7ffff7494dc8 2147483647>
        pointer_to_this <pointer_type 0x7ffff74b09d8>>
    addressable used public static SI exxengy4.f90:12:16 size <integer_cst
0x7ffff7494df8 32> unit-size <integer_cst 0x7ffff7494e10 4>
    align:32 warn_if_not_align:0 context <namespace_decl 0x7ffff7667260 modmpi>
chain <function_decl 0x7ffff7668200 exxengy>>


I am not quite sure whether the context is right or not:
  context <namespace_decl 0x7ffff7667260 modmpi> 
but it does not really look wrong, does it?