[Bug c++/84639] New: gcc/c-family/c-attribs.c:1822:27: runtime error: shift exponent -1 is negative

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84639

            Bug ID: 84639
           Summary: gcc/c-family/c-attribs.c:1822:27: runtime error: shift
                    exponent -1 is negative
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: marxin at gcc dot gnu.org
                CC: jason at gcc dot gnu.org, mpolacek at gcc dot gnu.org,
                    nathan at gcc dot gnu.org
  Target Milestone: ---

UBSAN gcc prints the error:

$ UBSAN_OPTIONS="print_stacktrace=1" ./xg++ -B.
/home/marxin/Programming/gcc/gcc/testsuite/g++.dg/cpp0x/alignas12.C
/home/marxin/Programming/gcc/gcc/testsuite/g++.dg/cpp0x/alignas12.C:6:10:
error: ‘alignas’ argument has non-integral type ‘<unresolved overloaded
function type>’
 alignas (f < int >) char c;  // { dg-error "non-integral type" }
          ^~~~~~~~~
../../gcc/c-family/c-attribs.c:1822:27: runtime error: shift exponent -1 is
negative
    #0 0x5e311c in common_handle_aligned_attribute
../../gcc/c-family/c-attribs.c:1822
    #1 0xe29d06 in decl_attributes(tree_node**, tree_node*, int, tree_node*)
../../gcc/attribs.c:685
    #2 0x991bd9 in cplus_decl_attributes(tree_node**, tree_node*, int)
../../gcc/cp/decl2.c:1546
    #3 0x95790d in start_decl(cp_declarator const*, cp_decl_specifier_seq*,
int, tree_node*, tree_node*, tree_node**) ../../gcc/cp/decl.c:5047
    #4 0xb95381 in cp_parser_init_declarator ../../gcc/cp/parser.c:19587
    #5 0xbaef4d in cp_parser_simple_declaration ../../gcc/cp/parser.c:13053
    #6 0xbb230e in cp_parser_block_declaration ../../gcc/cp/parser.c:12878
    #7 0xbc4460 in cp_parser_declaration ../../gcc/cp/parser.c:12776
    #8 0xbc66a1 in cp_parser_declaration_seq_opt ../../gcc/cp/parser.c:12652
    #9 0xbc7628 in cp_parser_translation_unit ../../gcc/cp/parser.c:4559
    #10 0xbc7628 in c_parse_file() ../../gcc/cp/parser.c:38880
    #11 0xeec35c in c_common_parse_file() ../../gcc/c-family/c-opts.c:1132
    #12 0x25a2cdc in compile_file ../../gcc/toplev.c:455
    #13 0x77e2e9 in do_compile ../../gcc/toplev.c:2132
    #14 0x77e2e9 in toplev::main(int, char**) ../../gcc/toplev.c:2267
    #15 0x78117a in main ../../gcc/main.c:39
    #16 0x7fd52c3026e4 in __libc_start_main (/lib64/libc.so.6+0x206e4)
    #17 0x7812a8 in _start
(/home/marxin/Programming/gcc/objdir/gcc/cc1plus+0x7812a8)