https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105585
Bug ID: 105585
Summary: [12/13 Regression] Spurious stringop-overflow warning
with <atomic>
Product: gcc
Version: 12.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: ed at catmur dot uk
Target Milestone: ---
Reduced (from code in abseil-cpp):
#include <atomic>
struct S {
int i;
std::atomic<int> a;
};
S* q();
void f();
void g(bool b) {
auto p = b ? q() : nullptr;
++p->a;
if (p)
f();
}
In file included from atomic:41,
from <source>:1:
In member function 'std::__atomic_base<_IntTp>::__int_type
std::__atomic_base<_IntTp>::operator++() [with _ITp = int]',
inlined from 'void g(bool)' at <source>:10:3:
bits/atomic_base.h:385:34: warning: 'unsigned int __atomic_add_fetch_4(volatile
void*, unsigned int, int)' writing 4 bytes into a region of size 0 overflows
the destination [-Wstringop-overflow=]
385 | { return __atomic_add_fetch(&_M_i, 1, int(memory_order_seq_cst));
}
| ~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
