This has already been fixed in -current:

RCS file: /cvsroot/src/gnu/dist/binutils/opcodes/sparc-opc.c,v
revision 1.2
date: 2005/04/24 23:53:18;  author: christos;  state: Exp;  lines: +71 -109
Apply patch from the RedHat CVS tree. Avoids issue with -O3 using the
wrong registers with some opcodes, the error is:
Error: Illegal operands: There are only 32 single precision f registers; [0-31]
And the code to cause this is:
        return (cond) ? x : -x;
where x is double.


I'll request pullup to 3.0

Martin