https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109717
--- Comment #1 from Paul Smith <psmith at gnu dot org> ---
This same test case also causes spurious errors for -Wstringop-overflow :(
If I use this compile line with the same source file, I get these errors:
$ g++-13.1 -I/data/src/build/common/fmt/include -std=gnu++20
-Wstringop-overflow -O2 -c -o /tmp/fmt1.o /tmp/fmt1.cpp
In file included from
/data/src/build/x86_64-linux/cc/unknown/x86_64-unknown-linux-gnu/include/c++/13.1.0/vector:62,
from /tmp/fmt1.cpp:1:
In static member function 'static constexpr _Up* std::__copy_move<_IsMove,
true, std::random_access_iterator_tag>::__copy_m(_Tp*, _Tp*, _Up*) [with _Tp =
unsigned int; _Up = unsigned int; bool _IsMove = false]',
inlined from 'constexpr _OI std::__copy_move_a2(_II, _II, _OI) [with bool
_IsMove = false; _II = unsigned int*; _OI = unsigned int*]' at
/data/src/build/x86_64-linux/cc/unknown/x86_64-unknown-linux-gnu/include/c++/13.1.0/bits/stl_algobase.h:506:30,
inlined from 'constexpr _OI std::__copy_move_a1(_II, _II, _OI) [with bool
_IsMove = false; _II = unsigned int*; _OI = unsigned int*]' at
/data/src/build/x86_64-linux/cc/unknown/x86_64-unknown-linux-gnu/include/c++/13.1.0/bits/stl_algobase.h:533:42,
inlined from 'constexpr _OI std::__copy_move_a(_II, _II, _OI) [with bool
_IsMove = false; _II = unsigned int*; _OI = unsigned int*]' at
/data/src/build/x86_64-linux/cc/unknown/x86_64-unknown-linux-gnu/include/c++/13.1.0/bits/stl_algobase.h:540:31,
inlined from 'constexpr _OI std::copy(_II, _II, _OI) [with _II = unsigned
int*; _OI = unsigned int*]' at
/data/src/build/x86_64-linux/cc/unknown/x86_64-unknown-linux-gnu/include/c++/13.1.0/bits/stl_algobase.h:633:7,
inlined from 'static _ForwardIterator
std::__uninitialized_copy<true>::__uninit_copy(_InputIterator, _InputIterator,
_ForwardIterator) [with _InputIterator = unsigned int*; _ForwardIterator =
unsigned int*]' at
/data/src/build/x86_64-linux/cc/unknown/x86_64-unknown-linux-gnu/include/c++/13.1.0/bits/stl_uninitialized.h:147:27,
inlined from '_ForwardIterator std::uninitialized_copy(_InputIterator,
_InputIterator, _ForwardIterator) [with _InputIterator = unsigned int*;
_ForwardIterator = unsigned int*]' at
/data/src/build/x86_64-linux/cc/unknown/x86_64-unknown-linux-gnu/include/c++/13.1.0/bits/stl_uninitialized.h:185:15,
inlined from 'constexpr void fmt::v9::basic_memory_buffer<T, SIZE,
Allocator>::grow(size_t) [with T = unsigned int; long unsigned int SIZE = 32;
Allocator = std::allocator<unsigned int>]' at
/data/src/build/common/fmt/include/fmt/format.h:925:26,
inlined from 'constexpr void
fmt::v9::detail::buffer<T>::try_reserve(size_t) [with T = unsigned int]' at
/data/src/build/common/fmt/include/fmt/core.h:928:39,
inlined from 'constexpr void
fmt::v9::detail::buffer<T>::try_reserve(size_t) [with T = unsigned int]' at
/data/src/build/common/fmt/include/fmt/core.h:927:24,
inlined from 'constexpr void fmt::v9::detail::buffer<T>::try_resize(size_t)
[with T = unsigned int]' at
/data/src/build/common/fmt/include/fmt/core.h:919:16,
inlined from 'constexpr void fmt::v9::basic_memory_buffer<T, SIZE,
Allocator>::resize(size_t) [with T = unsigned int; long unsigned int SIZE = 32;
Allocator = std::allocator<unsigned int>]' at
/data/src/build/common/fmt/include/fmt/format.h:897:63,
inlined from 'constexpr void fmt::v9::detail::bigint::assign(UInt) [with
UInt = long unsigned int; typename std::enable_if<(std::is_same<UInt, long
unsigned int>::value || std::is_same<UInt, __int128 unsigned>::value),
int>::type <anonymous> = 0]' at
/data/src/build/common/fmt/include/fmt/format.h:2792:19,
inlined from 'constexpr void fmt::v9::detail::bigint::operator=(Int) [with
Int = int]' at /data/src/build/common/fmt/include/fmt/format.h:2813:11,
inlined from 'constexpr void fmt::v9::detail::bigint::assign_pow10(int)' at
/data/src/build/common/fmt/include/fmt/format.h:2886:32:
/data/src/build/x86_64-linux/cc/unknown/x86_64-unknown-linux-gnu/include/c++/13.1.0/bits/stl_algobase.h:437:30:
warning: 'void* __builtin_memmove(void*, const void*, long unsigned int)'
writing between 5 and 9223372036854775807 bytes into a region of size 4
overflows the destination [-Wstringop-overflow=]
437 | __builtin_memmove(__result, __first, sizeof(_Tp) * _Num);
| ~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Again that same test works fine with GCC 11.3. It seems that overflow
detection in GCC 13.1 is really broken.
