[HP aCC 6.16] bogus warning #20200: potential null pointer dereference

$ cat t.cpp && aCC +w -c -V t.cpp
int bar ();

int foo (int *a, int i)
{
    int *p;
    if (i) p = a; else p = 0;

    if (i)
        return *p;
    return 0;
}

int foobar (int *a, int i)
{
    int *p;
    if (i) p = a; else p = 0;

    if (bar ())
        if (i)
            return *p;
    return 0;
}
aCC: HP C/aC++ B3910B A.06.16 [Nov 26 2007]
"t.cpp", line 20, procedure foobar: warning #20200-D: Potential null pointer
          dereference through p is detected (null definition:t.cpp, line 16)