Eliminate the checked cast from get_call_reg_set_usage

Eliminate the checked cast from get_call_reg_set_usage

gcc/ChangeLog
2014-09-05  David Malcolm  <dmalcolm@redhat.com>

	* caller-save.c (setup_save_areas): Strengthen local "insn" from
	rtx to rtx_insn *.
	* final.c (get_call_reg_set_usage): Likewise for first param,
	eliminating a checked cast.
	* regs.h (get_call_reg_set_usage): Likewise for first param.
	* resource.c (mark_set_resources): Introduce local rtx_call_insn *
	"call_insn" for the case of a MARK_SRC_DEST_CALL via a checked
	cast, replacing references to "x" with "call_insn" where
	appropriate.
	(mark_target_live_regs): Strengthen local "real_insn" from rtx to
	rtx_insn *, adding a checked cast.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@214962 138bc75d-0d04-0410-961f-82ee72b054a4