PR tree-optimization/21574
	* tree-ssa-ccp.c (likely_value): If the right hand side is a
	constant, return CONSTANT.
	(ccp_lattice_meet): Use operand_equal_p instead of simple_cst_equal.
	(ccp_fold, visit_assignment): Likewise.
	(evaluate_stmt): Handle UNDEFINED and UNKNOWN_VAL the same way.

From-SVN: r103206