mmix.md: Update FIXME to not mention define_constants.

mmix.md: Update FIXME to not mention define_constants.

	* config/mmix/mmix.md: Update FIXME to not mention
	define_constants.
	(MMIX_rJ_REGNUM): New define_constants constant.
	("movqi", "movsi", "movdi", "*movdicc_real_foldable",
	"*movdicc_real"): Adjust contraints formatting.
	("*bCC_foldable"): Add %+ for P in output format and delete FIXME
	for branch prediction.
	("*bCC", "*bCC_inverted_foldable", "*bCC_inverted"): Add %+ in
	output template.
	("*call_real", "*call_value_real", "nonlocal_goto_receiver",
	"*nonlocal_goto_receiver_expanded"): Use MMIX_rJ_REGNUM instead of
	number.  Delete related FIXMEs.
	* config/mmix/mmix.h (MMIX_INCOMING_RETURN_ADDRESS_REGNUM): Change
	from number to MMIX_rJ_REGNUM.
	(TARGET_MASK_BRANCH_PREDICT): New.
	(TARGET_DEFAULT): Change to TARGET_MASK_BRANCH_PREDICT.
	(TARGET_SWITCHES): Update comment.  Correct -mno-toplevel-symbols
	value.  Add -mbranch-predict and -mno-branch-predict.
	(TARGET_VERSION): Drop date.
	(ADDITIONAL_REGISTER_NAMES): Use MMIX_rJ_REGNUM, not number.
	* config/mmix/mmix.c (mmix_encode_section_info): Correct condition
	for finding out global symbols.
	(mmix_asm_output_labelref): Revert condition for global symbol.
	(mmix_print_operand): <case '+'>: Emit P for a likely branch.
	(mmix_print_operand_punct_valid_p): A '+' is valid.

From-SVN: r48448