genmatch.c (comparison_code_p): New predicate.

genmatch.c (comparison_code_p): New predicate.

2016-06-01  Richard Biener  <rguenther@suse.de>

	* genmatch.c (comparison_code_p): New predicate.
	(swap_tree_comparison): New function.
	(commutate): Add for_vec parameter to append new for entries.
	Support commutating relational operators by swapping it alongside
	operands.
	(lower_commutative): Adjust.
	(dt_simplify::gen): Do not pass artificial operators to gen
	functions.
	(decision_tree::gen): Do not add artificial operators as parameters.
	(parser::parse_expr): Verify operator commutativity when :c is
	applied.  Allow :C to override this.
	* match.pd: Adjust patterns to use :C instead of :c where required.

From-SVN: r236977