gcse.c's modify_mem_list is a list of insns

gcse.c's modify_mem_list is a list of insns

gcc/ChangeLog:
2014-09-08  David Malcolm  <dmalcolm@redhat.com>

	* gcse.c (modify_mem_list): Strengthen this variable from
	vec<rtx> * to vec<rtx_insn *> *.
	(vec_rtx_heap): Strengthen this typedef from vec<rtx> to
	vec<rtx_insn *>.
	(load_killed_in_block_p): Strengthen local "list" from vec<rtx> to
	vec<rtx_insn *>, and local "setter" from rtx to rtx_insn *.
	(record_last_mem_set_info): Strengthen param "insn" from rtx to
	rtx_insn *.
	(record_last_set_info): Likewise for local "last_set_insn".

From-SVN: r215027