[Bug c/56523] -Wunitialized is described to be enabled by -Wall

[corentinjabot at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56523

--- Comment #2 from corentinjabot at gmail dot com 2013-03-04 17:33:26 UTC ---
Actually after a few more test it works correctly but the statement "This
enables some extra warning flags that are not enabled by -Wall." is confusing
since the to set of options overlap. 

I also tested with the following c++ snippet:

#include <iostream>
class A {
public:
    A() {}
    bool foo;
    void bar() {
        if(foo)
            std::cout << "Foo\n";
    }
};

int main () {
    A a;
    a.bar();
    return 0;
}

The uninitialized variable is detected only with -O1. It is vaguely documented
but that behavior seems quite odd and unexpected when you are not aware of it.