https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104475
Bug ID: 104475
Summary: Wstringop-overflow + atomics incorrect warning on
dynamic object
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: thiago at kde dot org
Target Milestone: ---
Created attachment 52399
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=52399&action=edit
qfutureinterface.cpp preprocessed
In:
static inline int switch_on(QAtomicInt &a, int which)
{
return a.fetchAndOrRelaxed(which) | which;
}
static inline int switch_off(QAtomicInt &a, int which)
{
return a.fetchAndAndRelaxed(~which) & ~which;
}
void QFutureInterfaceBase::setThrottled(bool enable)
{
QMutexLocker lock(&d->m_mutex);
if (enable) {
switch_on(d->state, Throttled);
} else {
switch_off(d->state, Throttled);
if (!(d->state.loadRelaxed() & suspendingOrSuspended))
d->pausedWaitCondition.wakeAll();
}
}
Compiling the attached preprocessed sources with:
g++ -Wall -Wextra -march=haswell -O2 -c -o /dev/null qfutureinterface.cpp.ii
Produces:
In member function ‘std::__atomic_base<_IntTp>::__int_type
std::__atomic_base<_IntTp>::fetch_or(__int_type, std::memory_order) [with _ITp
= int]’,
inlined from ‘static T QAtomicOps<X>::fetchAndOrRelaxed(std::atomic<T>&,
typename QAtomicAdditiveType<T>::AdditiveT) [with T = int; X = int]’ at
/home/tjmaciei/obj/qt/qt6/qtbase/include/QtCore/../../../../../../src/qt/qt6/qtbase/src/corelib/thread/qatomic_cxx11.h:449:33,
inlined from ‘T QBasicAtomicInteger<T>::fetchAndOrRelaxed(T) [with T =
int]’ at
/home/tjmaciei/obj/qt/qt6/qtbase/include/QtCore/../../../../../../src/qt/qt6/qtbase/src/corelib/thread/qbasicatomic.h:168:36,
inlined from ‘int switch_on(QAtomicInt&, int)’ at
/home/tjmaciei/src/qt/qt6/qtbase/src/corelib/thread/qfutureinterface.cpp:59:31,
inlined from ‘void QFutureInterfaceBase::setThrottled(bool)’ at
/home/tjmaciei/src/qt/qt6/qtbase/src/corelib/thread/qfutureinterface.cpp:71:18:
/home/tjmaciei/dev/gcc/include/c++/12.0.1/bits/atomic_base.h:648:33: warning:
‘unsigned int __atomic_or_fetch_4(volatile void*, unsigned int, int)’ writing 4
bytes into a region of size 0 overflows the destination [-Wstringop-overflow=]
648 | { return __atomic_fetch_or(&_M_i, __i, int(__m)); }
| ~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
In member function ‘std::__atomic_base<_IntTp>::__int_type
std::__atomic_base<_IntTp>::fetch_and(__int_type, std::memory_order) [with _ITp
= int]’,
inlined from ‘static T QAtomicOps<X>::fetchAndAndRelaxed(std::atomic<T>&,
typename QAtomicAdditiveType<T>::AdditiveT) [with T = int; X = int]’ at
/home/tjmaciei/obj/qt/qt6/qtbase/include/QtCore/../../../../../../src/qt/qt6/qtbase/src/corelib/thread/qatomic_cxx11.h:425:34,
inlined from ‘T QBasicAtomicInteger<T>::fetchAndAndRelaxed(T) [with T =
int]’ at
/home/tjmaciei/obj/qt/qt6/qtbase/include/QtCore/../../../../../../src/qt/qt6/qtbase/src/corelib/thread/qbasicatomic.h:159:37,
inlined from ‘int switch_off(QAtomicInt&, int)’ at
/home/tjmaciei/src/qt/qt6/qtbase/src/corelib/thread/qfutureinterface.cpp:64:32,
inlined from ‘void QFutureInterfaceBase::setThrottled(bool)’ at
/home/tjmaciei/src/qt/qt6/qtbase/src/corelib/thread/qfutureinterface.cpp:73:19:
/home/tjmaciei/dev/gcc/include/c++/12.0.1/bits/atomic_base.h:638:34: warning:
‘unsigned int __atomic_fetch_and_4(volatile void*, unsigned int, int)’ writing
4 bytes into a region of size 0 overflows the destination
[-Wstringop-overflow=]
638 | { return __atomic_fetch_and(&_M_i, __i, int(__m)); }
| ~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
GCC Git commit 1ce5395977f37e8d0c03394f7b932a584ce85cc7, built today.
