E500 subreg fixes

[Aldy Hernandez]

 > OK to commit to mainline, 4.2, 4.1?

 > 2006-11-21  Joseph Myers  <joseph@codesourcery.com>

 > 	* spe.md (SPE64): New mode macro.
 > 	(mov_sidf_e500_subreg0): Change to mov_si<mode>_e500_subreg0.  Add
 > 	memory load.
 > 	(mov_si<mode>_e500_subreg0_2): New.
 > 	(mov_sidf_e500_subreg4): Change to mov_si<mode>_e500_subreg4.  Add
 > 	memory load.
 > 	(mov_si<mode>_e500_subreg4_2): New.
 > 	* predicates.md (input_operand): Do not allow invalid E500
 > 	subregs.
 > 	(rs6000_nonimmediate_operand): Check for invalid E500 subregs also
 > 	if TARGET_SPE.
 > 	* rs6000.c (invalid_e500_subreg): Check for subregs involving
 > 	DFmode if TARGET_E500_DOUBLE.  Check for subregs involving vector
 > 	modes if TARGET_SPE.

OK for mainline.  OK for the branches, provided they are open for
regressions, and it's ok with the appropriate RMs.

Thanks.