[RFA]: fix ia64 long double support

[J. Johnston]

Kevin Buettner wrote:
> On Dec 4,  5:37pm, J. Johnston wrote:
> 
> 
>>Fix to a couple of problems.  First of all, we aren't setting up a long double 
>>format for the architecture so it defaults to double when you try and print a 
>>long double value via gdb.
>>
>>Although the ia64 has a special long double format it specifies,
>>this format is only valid for register values.  Values in memory use
>>the x86 extended float format which is 80 bits.  Register long
>>doubles are 82 bits (2 more bits of exponent).
> 
> 
> So what happens when we try to print a long double in a register?
> 

The routine ia64_register_type() returns builtin_type_ia64_ext for the 
floating-point registers which is the 82-bit register variant.

> 
>>Anyway, this simple change fixes it so long doubles print correctly.
>>
>>Ok to commit?
> 
> 
> Sure.  I'm guessing that we still won't always print long doubles correctly,
> but it looks like this gets us closer...
>
> Kevin
>