fix for PR 4447: is this really correct?

[Kriang Lerdsuwanakij]

Joe Buck wrote:
> 
> OK.  Mark had approved applying this patch to the 3_0_release branch,
> so I guess it is the thing to do.  I don't understand why the ABI is
> written this way, though.  It seems odd, and since the expression must
> be constant, I don't see why it was thought better to leave it unevaluated.
> 
> But, are you confident that all operators are now covered, or is it
> possible that there's another ICE lurking out there if a user tries a
> complicated expression?
> 
> Joe

The only operator missing is the reinterpret_cast operator.  Handling it
is somewhat messy especially when converting pointers and references - 
like mangling reinterpret_cast'ing pointer should be encoded as casting 
to void *  followed by casting to the desired type (in conformance with 
functional equivalent rule in 14.5.5.1 para 5-8).  

I think it's not so important for 3.0.3.  However, I plan to submit an 
implementation for 3.1.

--Kriang