fold-const.c (fold_binary_loc): Move bool_var != 0 -> bool_var and bool_var == 1 -> bool_var simplifications ...

2015-07-15  Richard Biener  <rguenther@suse.de>

	* fold-const.c (fold_binary_loc): Move bool_var != 0 -> bool_var
	and bool_var == 1 -> bool_var simplifications ...
	* match.pd: ... to patterns here.  Factor out negate_expr_p
	cases from the A - B -> A + (-B) patterns as negate_expr_p
	predicate and add a -(A + B) -> (-B) - A pattern.

From-SVN: r225825