re PR bootstrap/6315 (sparc64 gcc -mhard-quad-float cannot compile libstdc++-v3)

	PR bootstrap/6315
	* config/sparc/sparc.md (movtf reg<-reg split): Allow spliting
	even if hard quad and register is not floating.
	(movtf reg<-mem split): Disallow splitting if hard quad and
	register is floating.
	(movtf mem<-reg split): Likewise.
	* config/sparc/sparc.c (fp_register_operand): New predicate.
	* config/sparc/sparc.h (PREDICATE_CODES): Add fp_register_operand.

	* gcc.dg/20020416-1.c: New test.

From-SVN: r52412