tree-ssa-alias.c (maybe_skip_until): Cache also at the point of the first store we visit in a basic-block.

2011-10-12  Richard Guenther  <rguenther@suse.de>

	* tree-ssa-alias.c (maybe_skip_until): Cache also at the point
	of the first store we visit in a basic-block.
	(get_continuation_for_phi): Search for a candidate VUSE that
	might dominates all others.  Do pairwise disambiguation against
	that candidate.

From-SVN: r179858