re PR target/26459 (gcc fails to build on powerpc e500-double targets)

	PR target/26459
	* config/rs6000/rs6000.h (CANNOT_CHANGE_MODE_CLASS): Limit 2003-12-08
	change to FLOAT_REGS.

From-SVN: r112561

gcc/ChangeLog

 2006-03-31  Alan Modra  <amodra@bigpond.net.au>
 
+	PR target/26459
+	* config/rs6000/rs6000.h (CANNOT_CHANGE_MODE_CLASS): Limit 2003-12-08
+	change to FLOAT_REGS.
+
 	* config/rs6000/rs6000.c (rs6000_explicit_options): Add ieee.
 	(rs6000_override_options): Use it.
 	(rs6000_handle_option): Set it.  Set rs6000_explicit_options.abi

gcc/config/rs6000/rs6000.h

@@ -1112,22 +1112,19 @@ enum reg_class
   ? 1                                                                   \
   : ((GET_MODE_SIZE (MODE) + UNITS_PER_WORD - 1) / UNITS_PER_WORD))
 
-
-/* Return a class of registers that cannot change FROM mode to TO mode.  */
-
-#define CANNOT_CHANGE_MODE_CLASS(FROM, TO, CLASS)			  \
-  (!TARGET_IEEEQUAD							  \
-   && GET_MODE_SIZE (FROM) >= 8 && GET_MODE_SIZE (TO) >= 8		  \
-   ? 0									  \
-   : GET_MODE_SIZE (FROM) != GET_MODE_SIZE (TO)				  \
-   ? reg_classes_intersect_p (FLOAT_REGS, CLASS)			  \
-   : (TARGET_E500_DOUBLE && (((TO) == DFmode) + ((FROM) == DFmode)) == 1) \
-   ? reg_classes_intersect_p (GENERAL_REGS, CLASS)			  \
-   : (TARGET_E500_DOUBLE && (((TO) == DImode) + ((FROM) == DImode)) == 1) \
-   ? reg_classes_intersect_p (GENERAL_REGS, CLASS)			  \
-   : (TARGET_SPE && (SPE_VECTOR_MODE (FROM) + SPE_VECTOR_MODE (TO)) == 1) \
-   ? reg_classes_intersect_p (GENERAL_REGS, CLASS)			  \
-   : 0)
+/* Return nonzero if for CLASS a mode change from FROM to TO is invalid.  */
+
+#define CANNOT_CHANGE_MODE_CLASS(FROM, TO, CLASS)			\
+  (GET_MODE_SIZE (FROM) != GET_MODE_SIZE (TO)				\
+   ? ((GET_MODE_SIZE (FROM) < 8 || GET_MODE_SIZE (TO) < 8		\
+       || TARGET_IEEEQUAD)						\
+      && reg_classes_intersect_p (FLOAT_REGS, CLASS))			\
+   : (((TARGET_E500_DOUBLE						\
+	&& ((((TO) == DFmode) + ((FROM) == DFmode)) == 1		\
+	    || (((TO) == DImode) + ((FROM) == DImode)) == 1))		\
+       || (TARGET_SPE							\
+	   && (SPE_VECTOR_MODE (FROM) + SPE_VECTOR_MODE (TO)) == 1))	\
+      && reg_classes_intersect_p (GENERAL_REGS, CLASS)))
 
 /* Stack layout; function entry, exit and calling.  */