make more vars auto_sbitmaps

make more vars auto_sbitmaps

gcc/ChangeLog:

2017-05-13  Trevor Saunders  <tbsaunde+gcc@tbsaunde.org>

	* ddg.c (find_nodes_on_paths): Use auto_sbitmap.
	(longest_simple_path): Likewise.
	* shrink-wrap.c (spread_components): Likewise.
	(disqualify_problematic_components): Likewise.
	(emit_common_heads_for_components): Likewise.
	(emit_common_tails_for_components): Likewise.
	(insert_prologue_epilogue_for_components): Likewise.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@248025 138bc75d-0d04-0410-961f-82ee72b054a4