https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111499
Bug ID: 111499
Summary: std::vector<uin8_t> less operator< doesn't compile
with optimalisation due to __builtin_memcmp
Product: gcc
Version: og12 (devel/omp/gcc-12)
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: mlachowicz at outlook dot com
Target Milestone: ---
Hi,
Would like to report bug in std::vector<uint8_t> less operator.
version of GCC: gcc 12.2, gcc 12.3, gcc 13.1, gcc 13.2
GNU C++20 (GCC) version 12.2.0 (x86_64-unknown-linux-gnu)
compiled by GNU C version 12.2.0, GMP version 6.2.1, MPFR version 4.2.0,
MPC version 1.3.1, isl version isl-0.20-GMP
system type: (not related to system)
the options given when GCC was configured/built: (not related)
the complete command line that triggers the bug:
g++ -Werror -std=c++20 -O1 f.cpp
the compiler output (error messages, warnings, etc.):
In file included from
/opt/compiler-explorer/gcc-12.2.0/include/c++/12.2.0/vector:60,
from <source>:1:
In function 'constexpr decltype (__comp((* __first1), (* __first2)))
std::lexicographical_compare_three_way(_InputIter1, _InputIter1, _InputIter2,
_InputIter2, _Comp) [with _InputIter1 = __gnu_cxx::__normal_iterator<const
unsigned char*, vector<unsigned char> >; _InputIter2 =
__gnu_cxx::__normal_iterator<const unsigned char*, vector<unsigned char> >;
_Comp = __detail::_Synth3way]',
inlined from 'constexpr std::__detail::__synth3way_t<_T1>
std::operator<=>(const vector<_Tp, _Alloc>&, const vector<_Tp, _Alloc>&) [with
_Tp = unsigned char; _Alloc = allocator<unsigned char>]' at
/opt/compiler-explorer/gcc-12.2.0/include/c++/12.2.0/bits/stl_vector.h:2056:52,
inlined from 'bool f(const std::vector<unsigned char>&)' at <source>:6:12:
/opt/compiler-explorer/gcc-12.2.0/include/c++/12.2.0/bits/stl_algobase.h:1843:41:
error: 'int __builtin_memcmp(const void*, const void*, long unsigned int)'
specified bound [9223372036854775808, 18446744073709551615] exceeds maximum
object size 9223372036854775807 [-Werror=stringop-overread]
1843 | = __builtin_memcmp(&*__first1, &*__first2, __len)
<=> 0;
| ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
cc1plus: all warnings being treated as errors
Compiler returned: 1
Complete set of source files (see below):
https://godbolt.org/z/rzznsffne
#include <vector>
bool f(const std::vector<unsigned char> &v)
{
std::vector<unsigned char> w;
return v < w;
}
int main () {}
Other:
Bug exists only for unsigned char. Doesn't exist for signed char.
Bug exists only with -O1 option. Doesn't exist with -O0.
Let me know if you need more detailed information.
Kind regards,
Michał
