fold-const.c (tree_expr_nonzero_p): Add function prototype.

fold-const.c (tree_expr_nonzero_p): Add function prototype.

	* fold-const.c (tree_expr_nonzero_p): Add function prototype.
	(fold) <EQ_EXPR>: Move tree_expr_nonzero_p optimization from
	fold_relational_const to here, i.e. "(x | 5) == 0" -> false.
	(fold) (UNEQ_EXPR>: Add optimizations for unordered comparisons
	of the form "x op x" where op is UNLE, UNGE, UNEQ or LTGT.
	(fold_relational_const): Tidy up handling of floating point
	comparisons by calling real_compare.  Remove tree_expr_nonzero_p
	transformation; fold_relational_const assumes constant operands.

From-SVN: r84916