-fstrict-aliasing, -Wstrict-aliasing=2, and indirect conversions

[Harald van DÄk <truedfx at gentoo dot org>]

Hello,

int main() {
    int a = 1;
    short *b = (short *) (char *) &a;
    *b = 2;
    return a;
}

This simple program returns 1 when compiled with -O2 -fstrict-aliasing, 
and 2 when compiled with -O2 -fno-strict-aliasing. It does not produce 
any warnings with -Wstrict-aliasing=2. According to the documentation:

`-Wstrict-aliasing=2'
     This option is only active when `-fstrict-aliasing' is active.  It
     warns about all code which might break the strict aliasing rules
     that the compiler is using for optimization.  This warning catches
     all cases, but it will also give a warning for some ambiguous
     cases that are safe.

Is this a bug? If so, what is the bug? Is the warning missing, or is the 
optimization invalid? And are there any alternative options that really 
catch every aliasing problem?

I'm using gcc 4.0.1 on i686-pc-linux-gnu.

Thanks in advance for any replies.