* config/i386/i386-features.h
	(general_scalar_chain::~general_scalar_chain): Add.
	(general_scalar_chain::insns_conv): New bitmap.
	(general_scalar_chain::n_sse_to_integer): New.
	(general_scalar_chain::n_integer_to_sse): Likewise.
	(general_scalar_chain::make_vector_copies): Adjust signature.
	* config/i386/i386-features.c
	(general_scalar_chain::general_scalar_chain): Outline,
	initialize new members.
	(general_scalar_chain::~general_scalar_chain): New.
	(general_scalar_chain::mark_dual_mode_def): Record insns
	we need to insert conversions at and count them.
	(general_scalar_chain::compute_convert_gain): Account
	for conversion instructions at chain boundary.
	(general_scalar_chain::make_vector_copies): Generate a single
	copy for a def by a specific insn.
	(general_scalar_chain::convert_registers): First populate
	defs_map, then make copies at out-of chain insns.

From-SVN: r274953