A Question Regarding Register classes

["Tal Agmon" <Tal dot Agmon at nsc dot com>]

Hi,

I'm working on the CRX pot of gcc which is intended to be contributed.
I have a general question:

I need to define a register class MAD_REGS for results of multiply 
accumulate instructions. 
When I define MAD_REGS registers NOT to be a in GENERAL_REGS everything 
works fine.
Yet, I wouldn't like that because it reduces GENERAL_REGS.  When I tried 
to use them also as
general registers on complicated functions, I got the error:

 error: unable to find a register to spill in class 'MAD_REGS'

I assume that this is because these registers were already used in other 
instruction and by the time
a mad instruction matches they are already "taken".
Is there's a way to declare 2 registers as a destination for some specific 
instructions but still 
get them available for reload of any other instruction (at least in 
function without  multiply accumulate 
instructions?)
 
Regards,
      Tal Agmon

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