compare-elim.c: Use rtx_insn

compare-elim.c: Use rtx_insn

gcc/
2014-08-22  David Malcolm  <dmalcolm@redhat.com>

	* compare-elim.c (struct comparison_use): Strengthen field "insn"
	from rtx to rtx_insn *.
	(struct comparison): Likewise, also for field "prev_clobber".
	(conforming_compare): Likewise for param "insn".
	(arithmetic_flags_clobber_p): Likewise.
	(find_flags_uses_in_insn): Likewise.
	(find_comparison_dom_walker::before_dom_children): Likewise for
	locals "insn", "next", "last_clobber".
	(try_eliminate_compare): Likewise for locals "insn", "bb_head".

From-SVN: r214302