* tracer.c (mark_bb_seen): Use SBITMAP_SIZE.

	* alias.c (MAX_ALIAS_LOOP_PASSES): Update comment with rationale,
	or rather a lack thereof.
	(init_alias_analysis): Propagate the latest information across
	the CFG in topological order to propagate as far as possible in
	each iteration.  Ignore debug insns.

From-SVN: r190602