What's the right behavior when overloading operator delete without overloading new? gcc and clang differ

The following code behaves differently with clang (version 5.0.0-3~16.04.1 on x86_64-pc-linux-gnu) and gcc (9.2.0).

void operator delete(void* ptr) noexcept {
    std::cout << "overloaded delete"<< std::endl;
    free(ptr);
}

int main() {
    int* pint = new int;
    delete pint; // clang doesn't go through overloaded operator delete, gcc does
}

gcc goes via the overloaded operator delete while clang avoids it preferring the global delete.

(When adding an overloaded operator new both compilers agree and go through both overloaded versions).

Code: http://coliru.stacked-crooked.com/a/0903bd53a8c04a9b