fold-const.c (fold_binary_loc): Remove -A CMP -B -> A CMP B and -A CMP CST -> A CMP -CST which is redundant...

2015-06-26  Richard Biener  <rguenther@suse.de>

	* fold-const.c (fold_binary_loc): Remove -A CMP -B -> A CMP B
	and -A CMP CST -> A CMP -CST which is redundant with a pattern
	in match.pd.
	Move (A | C) == D where C & ~D != 0 -> 0, (X ^ Y) ==/!= 0 -> X ==/!= Y,
	(X ^ Y) ==/!= {Y,X} -> {X,Y} ==/!= 0 and
	(X ^ C1) op C2 -> X op (C1 ^ C2) to ...
	* match.pd: ... patterns here.

	* gcc.dg/tree-ssa/forwprop-25.c: Adjust.

From-SVN: r225007