* config/mips/abi64.h (SETUP_INCOMING_VARARGS): Undefine.
	* config/mips/mips-protos.h (mips_setup_incoming_varargs): Declare.
	(function_arg): Constify CUMULATIVE_ARGS.
	(function_arg_partial_nregs, function_arg_pass_by_reference): Likewise.
	* config/mips/mips.h (UNITS_PER_FPVALUE): Zero when TARGET_SOFT_FLOAT.
	(UNITS_PER_DOUBLE): New macro.
	(SETUP_INCOMING_VARARGS): Define.  Use mips_setup_incoming_varargs.
	(CUMULATIVE_ARGS): Reformat.  Remove num_adjusts workaround and
	last_arg_fp field.  Replace arg_words and fp_arg_words with gp_regs,
	fp_regs and stack_words.
	(EABI_FLOAT_VARARGS_P): New macro.
	* config/mips/mips.c (struct mips_arg_info): New.
	(mips_arg_info): New function.
	(function_arg_advance): Use it.  Add adjustment instructions here
	rather than in function_arg.
	(function_arg): Constify CUMULATIVE_ARGS.  Use mips_arg_info.  Check
	for VOIDmode at the beginning of the function.
	(function_partial_nregs): Constify CUMULATIVE_ARGS.  Use mips_arg_info.
	(function_arg_pass_by_reference): Likewise.
	(mips_setup_incoming_varags): New, largely based on old abi64.h code.
	(mips_build_va_list): Test EABI_FLOAT_VARARGS_P.
	(mips_va_start): Likewise.  Use the new stack_words field of
	CUMULATIVE_ARGS to set up overflow area.  Reformat.
	(mips_va_arg): Test EABI_FLOAT_VARARGS_P.  Unify EABI handling of
	doubles and other types, aligning the overflow pointer for non-doubles
	too.  Remove some code duplication.  Replace hard-coded constants.

From-SVN: r51167