expmed.c (add_cost, [...]): Make arrays indexed by machine mode.

	* expmed.c (add_cost, neg_cost, sdiv_pow2_cheap, smod_pow2_cheap):
	Make arrays indexed by machine mode.  Rename negate_cost to neg_cost.
	(init_expmed): Initialize these cost arrays as appropriate.
	(store_bit_field, extract_bit_field): Correct whitespace.
	(synth_mult, choose_mult_variant, expand_mult, expand_mult_highpart,
	expand_mult_highpart_optab, expand_divmod): Update uses of add_cost,
	neg_cost, sdiv_pow2_cheap, smod_pow2_cheap to index with mode,
	word_mode or compute_mode as appropriate.

From-SVN: r82743