https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113775
Bug ID: 113775
Summary: Bogus Wstringop-overflow in __atomic_load_n combined
with sanitizer flags
Product: gcc
Version: 13.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: disservin.social at gmail dot com
Target Milestone: ---
Created attachment 57330
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=57330&action=edit
reproduction
GCC emits a bogus warning in the attached reproduction when compiled with
sanitizers flags and O3.
-O3 -std=c++17 -Wall -fsanitize=undefined -fsanitize=address
See
In file included from
/opt/compiler-explorer/gcc-13.2.0/include/c++/13.2.0/atomic:41,
from <source>:1:
In member function 'std::__atomic_base<_IntTp>::__int_type
std::__atomic_base<_IntTp>::load(std::memory_order) const [with _ITp = bool]',
inlined from 'std::atomic<bool>::operator bool() const' at
/opt/compiler-explorer/gcc-13.2.0/include/c++/13.2.0/atomic:87:26,
inlined from 'void Foo::foo()' at <source>:22:32:
/opt/compiler-explorer/gcc-13.2.0/include/c++/13.2.0/bits/atomic_base.h:505:31:
warning: 'unsigned char __atomic_load_1(const volatile void*, int)' writing 1
byte into a region of size 0 overflows the destination [-Wstringop-overflow=]
505 | return __atomic_load_n(&_M_i, int(__m));
| ~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~
In member function 'void Foo::foo()':
cc1plus: note: destination object is likely at address zero
Compiler returned: 0
I had a look at the bugs linked to
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88443, but I couldnt find a
similar scenario. Apologies if it is already known.
