https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117873
Bug ID: 117873
Summary: Spurious -Wmaybe-uninitialized warnings with -O3 for
static const std::regex
Product: gcc
Version: 15.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: hewillk at gmail dot com
Target Milestone: ---
https://godbolt.org/z/Mh64vqGcs
#include <regex>
int main() {
static const std::regex rgx{"hello"};
}
compile with -O3 -fsanitize=address -Wall, GCC gives:
In constructor 'std::function<_Res(_ArgTypes
...)>::function(std::function<_Res(_ArgTypes ...)>&&) [with _Res = bool;
_ArgTypes = {char}]',
inlined from
'std::__detail::_State<_Char_type>::_State(std::__detail::_State<_Char_type>&&)
[with _Char_type = char]' at
/opt/compiler-explorer/gcc-trunk-20241202/include/c++/15.0.0/bits/regex_automaton.h:152:4,
inlined from
'std::__detail::_State<_Char_type>::_State(std::__detail::_State<_Char_type>&&)
[with _Char_type = char]' at
/opt/compiler-explorer/gcc-trunk-20241202/include/c++/15.0.0/bits/regex_automaton.h:149:7,
inlined from 'std::__detail::_StateIdT
std::__detail::_NFA<_TraitsT>::_M_insert_subexpr_end() [with _TraitsT =
std::__cxx11::regex_traits<char>]' at
/opt/compiler-explorer/gcc-trunk-20241202/include/c++/15.0.0/bits/regex_automaton.h:293:24:
/opt/compiler-explorer/gcc-trunk-20241202/include/c++/15.0.0/bits/std_function.h:407:42:
warning: '*(std::function<bool(char)>*)((char*)&__tmp +
offsetof(std::__detail::_StateT,
std::__detail::_State<char>::<unnamed>.std::__detail::_State_base::<unnamed>)).std::function<bool(char)>::_M_invoker'
may be used uninitialized [-Wmaybe-uninitialized]
407 | : _Function_base(), _M_invoker(__x._M_invoker)
| ~~~~^~~~~~~~~~
