https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107986
Bug ID: 107986
Summary: [12/13 Regression] Bogus -Warray-bounds diagnostic
with std::sort
Product: gcc
Version: 12.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: rguenth at gcc dot gnu.org
Target Milestone: ---
PR104165 comment 2 talks about a test case reduced in
https://bugzilla.redhat.com/show_bug.cgi?id=2051783:
#include <algorithm>
bool cond;
int foo;
int func (void)
{
int a[3], qa = 0;
for(int i = 0; i < 3; i++)
if (cond)
a[qa++] = foo;
std::sort (a, a + qa);
return 0;
}
which still warns with both GCC 12 and 13 at -O2 -Wall like
In file included from
/home/rguenther/install/gcc-13/usr/local/include/c++/13.0.0/algorithm:61,
from t.C:1:
In function 'void std::__final_insertion_sort(_RandomAccessIterator,
_RandomAccessIterator, _Compare) [with _RandomAccessIterator = int*; _Compare =
__gnu_cxx::__ops::_Iter_less_iter]',
inlined from 'void std::__final_insertion_sort(_RandomAccessIterator,
_RandomAccessIterator, _Compare) [with _RandomAccessIterator = int*; _Compare =
__gnu_cxx::__ops::_Iter_less_iter]' at
/home/rguenther/install/gcc-13/usr/local/include/c++/13.0.0/bits/stl_algo.h:1854:5,
inlined from 'void std::__sort(_RandomAccessIterator,
_RandomAccessIterator, _Compare) [with _RandomAccessIterator = int*; _Compare =
__gnu_cxx::__ops::_Iter_less_iter]' at
/home/rguenther/install/gcc-13/usr/local/include/c++/13.0.0/bits/stl_algo.h:1950:31,
inlined from 'void std::__sort(_RandomAccessIterator,
_RandomAccessIterator, _Compare) [with _RandomAccessIterator = int*; _Compare =
__gnu_cxx::__ops::_Iter_less_iter]' at
/home/rguenther/install/gcc-13/usr/local/include/c++/13.0.0/bits/stl_algo.h:1942:5,
inlined from 'void std::sort(_RAIter, _RAIter) [with _RAIter = int*]' at
/home/rguenther/install/gcc-13/usr/local/include/c++/13.0.0/bits/stl_algo.h:4860:1,
inlined from 'int func()' at t.C:13:13:
/home/rguenther/install/gcc-13/usr/local/include/c++/13.0.0/bits/stl_algo.h:1859:32:
warning: array subscript 16 is outside array bounds of 'int [3]'
[-Warray-bounds=]
1859 | std::__insertion_sort(__first, __first + int(_S_threshold),
__comp);
|
~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
t.C: In function 'int func()':
t.C:8:7: note: at offset 64 into object 'a' of size 12
8 | int a[3], qa = 0;
| ^
I'll also note the lack of a non-included location in t.C.
