last_call_insn returns an rtx_call_insn *

last_call_insn returns an rtx_call_insn *

2014-08-19  David Malcolm  <dmalcolm@redhat.com>

	* emit-rtl.c (last_call_insn): Strengthen return type from rtx to
	rtx_call_insn *.
	* rtl.h (is_a_helper <rtx_call_insn *>::test): New overload,
	accepting an rtx_insn *.
	(last_call_insn): Strengthen return type from rtx to
	rtx_call_insn *.

From-SVN: r214186