[Bug tree-optimization/69483] New: gcc ICE on x86_64-linux-gnu with "expected class 'type', have 'exceptional' (error_mark) in useless_type_conversion_p"

[helloqirun at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69483

            Bug ID: 69483
           Summary: gcc ICE on x86_64-linux-gnu with "expected class
                    'type', have 'exceptional' (error_mark) in
                    useless_type_conversion_p"
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: helloqirun at gmail dot com
  Target Milestone: ---

The following code causes an ICE when compiled with the current gcc trunk on
x86_64-linux-gnu in both 32-bit and 64-bit modes. 

$ gcc-trunk -v
Using built-in specs.
COLLECT_GCC=gcc-trunk
COLLECT_LTO_WRAPPER=/home/absozero/trunk/root-gcc/libexec/gcc/x86_64-pc-linux-gnu/6.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc/configure --prefix=/home/absozero/trunk/root-gcc
--enable-languages=c,c++ --disable-werror --enable-multilib
Thread model: posix
gcc version 6.0.0 20160125 (experimental) [trunk revision 232792] (GCC)


$ gcc-trunk abc.c
abc.c:4:13: error: storage size of 'b' isn't known
 struct str1 b;
             ^

cc1: internal compiler error: tree check: expected class 'type', have
'exceptional' (error_mark) in useless_type_conversion_p, at gimple-expr.c:83
0xdd9de7 tree_class_check_failed(tree_node const*, tree_code_class, char
const*, int, char const*)
        ../../gcc/gcc/tree.c:9656
0x8cbe60 tree_class_check(tree_node*, tree_code_class, char const*, int, char
const*)
        ../../gcc/gcc/tree.h:3129
0x8cbe60 useless_type_conversion_p(tree_node*, tree_node*)
        ../../gcc/gcc/gimple-expr.c:83
0x8d2255 canonicalize_constructor_val(tree_node*, tree_node*)
        ../../gcc/gcc/gimple-fold.c:211
0x7807ca record_reference
        ../../gcc/gcc/cgraphbuild.c:54
0xdfcfd2 walk_tree_1(tree_node**, tree_node* (*)(tree_node**, int*, void*),
void*, hash_set<tree_node*, default_hash_traits<tree_node*> >*, tree_node*
(*)(tree_node**, int*, tree_node* (*)(tree_node**, int*, void*), void*,
hash_set<tree_node*, default_hash_traits<tree_node*> >*))
        ../../gcc/gcc/tree.c:11498
0xdfd4b7 walk_tree_1(tree_node**, tree_node* (*)(tree_node**, int*, void*),
void*, hash_set<tree_node*, default_hash_traits<tree_node*> >*, tree_node*
(*)(tree_node**, int*, tree_node* (*)(tree_node**, int*, void*), void*,
hash_set<tree_node*, default_hash_traits<tree_node*> >*))
        ../../gcc/gcc/tree.c:11575
0x781b04 record_references_in_initializer(tree_node*, bool)
        ../../gcc/gcc/cgraphbuild.c:404
0xe3cec7 varpool_node::analyze()
        ../../gcc/gcc/varpool.c:526
0x787e1a analyze_functions
        ../../gcc/gcc/cgraphunit.c:1129
0x788d98 symbol_table::finalize_compilation_unit()
        ../../gcc/gcc/cgraphunit.c:2535
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.





-------
$ cat abc.c
struct str3 {
  struct str1 *a;
};
struct str1 b;
struct str3 c = {&b};