2015-08-04  Richard Biener  <rguenther@suse.de>

	* gimple-fold.c (gimple_fold_stmt_to_constant_1): Canonicalize
	bool compares on RHS.
	* match.pd: Add X ==/!= !X is false/true pattern.

	* gcc.dg/tree-ssa/ssa-ccp-38.c: New testcase.

From-SVN: r226576