[powerpc64] fix for PR9680

[Aldy Hernandez]

I started to look at random PPC64 failures, and ran into this-- which 
coincidentally is really an SPE bug.

On PPC64, GPRs are 64-bits.  A GPR can therefore change modes from word 
size to V2SI.  The check in CANNOT_CHANGE_MODE_CLASS is for 
SPE_VECTOR_MODE (V2SImode); it should also check for TARGET_SPE.

I'm surprised this hasn't caused any more problems.

Committed to mainline.

David, could you please close the PR which you hold?

2003-06-01  Aldy Hernandez  <aldyh@redhat.com>

	* config/rs6000/rs6000.h (CANNOT_CHANGE_MODE_CLASS): Require
	TARGET_SPE for SPE_VECTOR_MODE.

Index: config/rs6000/rs6000.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/rs6000/rs6000.h,v
retrieving revision 1.275
diff -c -p -r1.275 rs6000.h
*** config/rs6000/rs6000.h	19 May 2003 17:39:50 -0000	1.275
--- config/rs6000/rs6000.h	1 Jun 2003 11:22:55 -0000
*************** enum reg_class
*** 1406,1412 ****
   #define CANNOT_CHANGE_MODE_CLASS(FROM, TO, CLASS)			\
     (GET_MODE_SIZE (FROM) != GET_MODE_SIZE (TO)				\
      ? reg_classes_intersect_p (FLOAT_REGS, CLASS)			\
!    : (SPE_VECTOR_MODE (FROM) + SPE_VECTOR_MODE (TO)) == 1		\
      ? reg_classes_intersect_p (GENERAL_REGS, CLASS) 			\
      : 0)

--- 1406,1412 ----
   #define CANNOT_CHANGE_MODE_CLASS(FROM, TO, CLASS)			\
     (GET_MODE_SIZE (FROM) != GET_MODE_SIZE (TO)				\
      ? reg_classes_intersect_p (FLOAT_REGS, CLASS)			\
!    : (TARGET_SPE && (SPE_VECTOR_MODE (FROM) + SPE_VECTOR_MODE (TO)) 
== 1) \
      ? reg_classes_intersect_p (GENERAL_REGS, CLASS) 			\
      : 0)