[Bug fortran/77679] New: ICE in fold_array_ctor_reference, at gimple-fold.c:5586

[gerhard.steinmetz.fortran@t-online.de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77679

            Bug ID: 77679
           Summary: ICE in fold_array_ctor_reference, at
                    gimple-fold.c:5586
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gerhard.steinmetz.fortran@t-online.de
  Target Milestone: ---

Affects versions 6 and 7, at -Os, -O1 or higher.
Invalid code with an uninitialized variable.


$ cat z1.f90
program p
   character(1) :: x(2)
   x = [character(n(1)) :: 'a', 'b']
end


$ gfortran-7-20160918 -O0 z1.f90
z1.f90:3:0:

    x = [character(n(1)) :: 'a', 'b']

Error: size of variable 'A.0' is too large


$ gfortran-7-20160918 -O2 z1.f90
z1.f90:4:0:

 end

internal compiler error: in fold_array_ctor_reference, at gimple-fold.c:5586
0x996e18 fold_array_ctor_reference
        ../../gcc/gimple-fold.c:5585
0x996e18 fold_ctor_reference(tree_node*, tree_node*, unsigned long, unsigned
long, tree_node*)
        ../../gcc/gimple-fold.c:5727
0x997055 fold_const_aggregate_ref_1(tree_node*, tree_node* (*)(tree_node*))
        ../../gcc/gimple-fold.c:5835
0x997eb0 gimple_fold_stmt_to_constant_1(gimple*, tree_node* (*)(tree_node*),
tree_node* (*)(tree_node*))
        ../../gcc/gimple-fold.c:5297
0xe114bf record_temporary_equivalences_from_stmts_at_dest
        ../../gcc/tree-ssa-threadedge.c:329
0xe12351 thread_through_normal_block
        ../../gcc/tree-ssa-threadedge.c:1049
0xe13d21 thread_across_edge(gcond*, edge_def*, bool, const_and_copies*,
avail_exprs_stack*, tree_node* (*)(gimple*, gimple*, avail_exprs_stack*))
        ../../gcc/tree-ssa-threadedge.c:1289
0xd44c90 dom_opt_dom_walker::thread_across_edge(edge_def*)
        ../../gcc/tree-ssa-dom.c:989
0xd44ea9 dom_opt_dom_walker::after_dom_children(basic_block_def*)
        ../../gcc/tree-ssa-dom.c:1408
0x1299c37 dom_walker::walk(basic_block_def*)
        ../../gcc/domwalk.c:307
0xd47988 execute
        ../../gcc/tree-ssa-dom.c:614