backport: common.opt (fira-select): New.

backport: common.opt (fira-select): New.

2018-07-18  Vladimir Makarov  <vmakarov@redhat.com>

	Merge with trunk.
	* common.opt (fira-select): New.  Choose the selection algorithm
	by default.
	* ira-costs.c (struct op_info, op_infos, insn_selection): New.
	(insn_selections): New.
	(CONST_POOL_OK_P, SMALL_REGISTER_CLASS_P, general_constant_p):
	New.
	(insn_constraints, setup_insn_alt): New.
	(record_address_regs): Forward declaration.
	(define_op_cost_from_alt): New.
	(scan_one_insn): Call setup_insn_alt and define_op_cost_from_alt
	for the selection algorithm.
	(find_costs_and_classes): Release insn_constraints and
	insn_selections.  Don't reuse already calculated pseudo classes
	for the selection algorithm.

From-SVN: r262866