* fold-const.c (tree_expr_nonnegative_p): Add support for
	floating point constants, addition and multiplication.

	* gcc.dg/builtins-21.c: New test case.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@67828 138bc75d-0d04-0410-961f-82ee72b054a4