C++ function pointer weirdness

[Volker Reichelt <reichelt at igpm dot rwth-aachen dot de>]

Yesterday the output of the following program changed
(probably due to the fix for PR19076):

======================================================================
template <typename T> int ref (T&)                { return 0; }
template <typename T> int ref (const T&)          { return 1; }
template <typename T> int ref (const volatile T&) { return 2; }
template <typename T> int ref (volatile T&)       { return 4; }

template <typename T> int ptr (T*)                { return 0; }
template <typename T> int ptr (const T*)          { return 8; }
template <typename T> int ptr (const volatile T*) { return 16; }
template <typename T> int ptr (volatile T*)       { return 32; }

void foo() {}

int main()
{
    return ref(foo) + ptr(&foo);
}
======================================================================

GCC 2.95.3 - 3.4.0 return 0, GCC 3.4.1 - 3.4.4-20050222 return 2,
and now mainline again returns 0.

So the question is: What is the correct return value?

Btw, we really should have this in the testsuite.

In any case, we have a wrong-code regression here, either on the
3.4 branch or on mainline. But before I open a PR I'd like to sort
out which is the correct behavior.

When the result changed in 3.4.1 I bugged Nathan (who caused this
change) about it, and he claimed that '2' is the correct result.
Intel's compiler indeed returns 2.

Regards,
Volker