[Bug c++/71464] New: ICE on invalid C++11 code (with redeclared constructor) at -Os on x86_64-linux-gnu: Segmentation fault

[su at cs dot ucdavis.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71464

            Bug ID: 71464
           Summary: ICE on invalid C++11 code (with redeclared
                    constructor) at -Os on x86_64-linux-gnu: Segmentation
                    fault
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: su at cs dot ucdavis.edu
  Target Milestone: ---

The following code causes an ICE when compiled with the current gcc trunk at
-Os only (but not at the other optimization levels) on x86_64-linux-gnu in both
32-bit and 64-bit modes.

This is a regression from 4.8.x as it seems to affect all 4.9.x and later. 


$ g++-trunk -v
Using built-in specs.
COLLECT_GCC=g++-trunk
COLLECT_LTO_WRAPPER=/usr/local/gcc-trunk/libexec/gcc/x86_64-pc-linux-gnu/7.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc-source-trunk/configure --enable-languages=c,c++,lto
--prefix=/usr/local/gcc-trunk --disable-bootstrap
Thread model: posix
gcc version 7.0.0 20160608 (experimental) [trunk revision 237196] (GCC) 
$ 
$ g++-4.8 -Os -c small.cpp
small.cpp:6:3: error: ‘B::B()’ cannot be overloaded
   B () {};
   ^
small.cpp:5:3: error: with ‘B::B()’
   B () {};
   ^
$ 
$ g++-trunk -Os -c small.cpp
small.cpp:6:3: error: ‘B::B()’ cannot be overloaded
   B () {};
   ^
small.cpp:5:3: error: with ‘B::B()’
   B () {};
   ^
small.cpp:6:9: internal compiler error: Segmentation fault
   B () {};
         ^
0xdaf09f crash_signal
        ../../gcc-source-trunk/gcc/toplev.c:335
0x1051d71 decl_assembler_name(tree_node*)
        ../../gcc-source-trunk/gcc/tree.c:668
0x8505e1 cdtor_comdat_group
        ../../gcc-source-trunk/gcc/cp/optimize.c:151
0x850fd3 maybe_thunk_body
        ../../gcc-source-trunk/gcc/cp/optimize.c:274
0x85251c maybe_clone_body(tree_node*)
        ../../gcc-source-trunk/gcc/cp/optimize.c:503
0x8179e7 expand_or_defer_fn_1(tree_node*)
        ../../gcc-source-trunk/gcc/cp/semantics.c:4193
0x817cb8 expand_or_defer_fn(tree_node*)
        ../../gcc-source-trunk/gcc/cp/semantics.c:4215
0x7a981b cp_parser_function_definition_after_declarator
        ../../gcc-source-trunk/gcc/cp/parser.c:25423
0x7ad610 cp_parser_late_parsing_for_member
        ../../gcc-source-trunk/gcc/cp/parser.c:26255
0x788e29 cp_parser_class_specifier_1
        ../../gcc-source-trunk/gcc/cp/parser.c:21570
0x788e29 cp_parser_class_specifier
        ../../gcc-source-trunk/gcc/cp/parser.c:21596
0x788e29 cp_parser_type_specifier
        ../../gcc-source-trunk/gcc/cp/parser.c:15836
0x79d223 cp_parser_decl_specifier_seq
        ../../gcc-source-trunk/gcc/cp/parser.c:12758
0x7aa711 cp_parser_simple_declaration
        ../../gcc-source-trunk/gcc/cp/parser.c:12299
0x7aab61 cp_parser_block_declaration
        ../../gcc-source-trunk/gcc/cp/parser.c:12246
0x7b3f40 cp_parser_declaration
        ../../gcc-source-trunk/gcc/cp/parser.c:12143
0x7b2a14 cp_parser_declaration_seq_opt
        ../../gcc-source-trunk/gcc/cp/parser.c:12022
0x7b2d48 cp_parser_translation_unit
        ../../gcc-source-trunk/gcc/cp/parser.c:4324
0x7b2d48 c_parse_file()
        ../../gcc-source-trunk/gcc/cp/parser.c:37502
0x9162f2 c_common_parse_file()
        ../../gcc-source-trunk/gcc/c-family/c-opts.c:1064
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.
$ 


------------------------


struct A {}; 

struct B : virtual A
{
  B () {};
  B () {};
};