On 26/09/24 04:44 +0000, Jason Mancini wrote:
Problem happens in 14.2.0, 13.2.0, 12.2.0
Doesn't seem to happen in 10.2.0 or 11.2.0
Only seems to happen for -std=c++17/14/11, but not for c++20/23/26.
Only seems to happen for -O2, but not -O0 / -O1 / -O3.
Happens for vector, but not deque or list.
Happens for vector<enum>, but not vector<int>.
Doesn't happen if the enum is declared outside the function.
Doesn't happen with clang++.
Issue replicates on godbolt.
The gcc-bugs mailing list is for automated email from our Bugzilla
database, not for reporting (or asking about) bugs. Emails sent to
this list will often be overlooked, missed, or just ignored.
This particular problem is a false positive warning (which you've
turned into an error with -Werror, so the solution is to not do that).
I don't think this false positive is already known, so it would be
great if you could report it as a bug, please see
https://gcc.gnu.org/bugs/
Thanks!
Thanks,
Jason Mancini
==============
g++ -c source.cc -Werror=nonnull -std=c++17 -O2
==============
#include <vector>
void f(bool p)
{
enum e { e1 };
std::vector<e> v;
if (p) { v = { e1 }; }
else { v = { e1 }; }
}
======= or even =======
#include <vector>
void f(bool p)
{
enum e { };
std::vector<e> v;
if (p) { v = { }; }
else { v = { }; }
}
==============
In file included from (...)/gcc-14.2.0/include/c++/14.2.0/vector:62,
from source.cc:1:
In static member function 'static _Up* std::__copy_move<_IsMove, true,
std::random_access_iterator_tag>::__copy_m(_Tp*, _Tp*, _Up*) [with _Tp = const
f(bool)::e; _Up = f(bool)::e; bool _IsMove = false]',
inlined from '_OI std::__copy_move_a2(_II, _II, _OI) [with bool _IsMove =
false; _II = const f(bool)::e*; _OI = f(bool)::e*]' at
(...)/gcc-14.2.0/include/c++/14.2.0/bits/stl_algobase.h:521:30,
inlined from '_OI std::__copy_move_a1(_II, _II, _OI) [with bool _IsMove =
false; _II = const f(bool)::e*; _OI = f(bool)::e*]' at
(...)/gcc-14.2.0/include/c++/14.2.0/bits/stl_algobase.h:548:42,
inlined from '_OI std::__copy_move_a(_II, _II, _OI) [with bool _IsMove =
false; _II = const f(bool)::e*; _OI = f(bool)::e*]' at
(...)/gcc-14.2.0/include/c++/14.2.0/bits/stl_algobase.h:555:31,
inlined from '_OI std::copy(_II, _II, _OI) [with _II = const f(bool)::e*;
_OI = f(bool)::e*]' at
(...)/gcc-14.2.0/include/c++/14.2.0/bits/stl_algobase.h:651:7,
inlined from 'void std::vector<_Tp, _Alloc>::_M_assign_aux(_ForwardIterator,
_ForwardIterator, std::forward_iterator_tag) [with _ForwardIterator = const f(bool)::e*;
_Tp = f(bool)::e; _Alloc = std::allocator<f(bool)::e>]' at
(...)/gcc-14.2.0/include/c++/14.2.0/bits/vector.tcc:343:19:
(...)/gcc-14.2.0/include/c++/14.2.0/bits/stl_algobase.h:452:30: error: argument
1 null where non-null expected [-Werror=nonnull]
452 | __builtin_memmove(__result, __first, sizeof(_Tp) * _Num);
| ~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
(...)/gcc-14.2.0/include/c++/14.2.0/bits/stl_algobase.h:452:30: note: in a call
to built-in function 'void* __builtin_memmove(void*, const void*, long unsigned
int)'
==============
EOM
