https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94747
Bug ID: 94747
Summary: Undefined behavior: integer overflow in
libsupc++/dyncast.cc
Product: gcc
Version: 7.5.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: hiraditya at msn dot com
Target Milestone: ---
Integer overflow reported by asan with the following stack trace. If this is
not
sufficient I can try to provide a repro
gcc/7.x/libstdc++-v3/libsupc++/dyncast.cc:53:11: runtime error: negation of 16
cannot be represented in type 'unsigned long'
> #0 in __dynamic_cast gcc/7.x/libstdc++-v3/libsupc++/dyncast.cc:53
> #1 in bool std::has_facet<std::ctype<char> >(std::locale const&)
> gcc/7.x/.../bits/locale_classes.tcc:110
> #2 in std::basic_ios<char, std::char_traits<char>
> >::_M_cache_locale(std::locale const&) gcc/7.x/.../bits/basic_ios.tcc:159
> #3 in std::basic_ios<char, std::char_traits<char>
> >::init(std::basic_streambuf<char, std::char_traits<char> >*)
> gcc/7.x/.../bits/basic_ios.tcc:132
> #4 in std::basic_ostream<char, std::char_traits<char>
> >::basic_ostream(std::basic_streambuf<char, std::char_traits<char> >*)
> gcc/7.x/.../ostream:85
> #5 in std::ios_base::Init::Init()
> gcc/7.x/libstdc++-v3/src/c++98/ios_init.cc:91
> #6 in __cxx_global_var_init gcc/7.x/.../iostream:74
