Re: New development branch: ia64-fp-model-branch

[Bradley Lucier <lucier at math dot purdue dot edu>]

On Nov 4, 2004, at 4:32 PM, Richard Henderson wrote:

> On Wed, Nov 03, 2004 at 10:22:53PM -0500, Bradley Lucier wrote:
> > I glanced at the design document; it seems that many of these changes
> > could also apply to getting an accurate back-end model of x86
> > floating-point arithmetic.  Is this part of your goal?
>
> Many of them can, yes.  But the biggest hurdle there is convincing
> reload to spill values in XFmode.

Ah, but one finds in the design document:

> __fpreg is an extended floating point type which provides user access 
> to the full width of the floating point registers. It has the 
> following properties:
>
>     * It is copied between registers and memory with 'fill/spill' 
> instructions that transfer the complete internal register content.

So this seems to be exactly what one needs.  What I don't understand 
(and what is quite limiting, it seems to me) is the reason for the next 
point:

>     * There is no way to write a constant with type __fpreg.

Brad