* builtins.c (fold_builtin_cos): Use fold_strip_sign_ops().
	(fold_builtin_hypot): Likewise.
	* fold-const.c (fold_strip_sign_ops): Handle "odd" builtins.
	
testsuite:
	* gcc.dg/builtins-20.c: Add more cases for stripping sign ops.

From-SVN: r118683