re PR tree-optimization/13962 ([tree-ssa] make "fold" use alias information to optimize pointer comparisons)

2016-04-29  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/13962
	PR tree-optimization/65686
	* tree-ssa-alias.h (ptrs_compare_unequal): Declare.
	* tree-ssa-alias.c (ptrs_compare_unequal): New function
	using PTA to compare pointers.
	* match.pd: Add pattern for pointer equality compare simplification
	using ptrs_compare_unequal.

	* gcc.dg/uninit-pr65686.c: New testcase.

From-SVN: r235622