n := n.(*ir.UnaryExpr)
		a := s.expr(n.X)
		return s.newValue1(ssa.OpIData, n.Type(), a)

	case ir.OMAKEFACE:
		n := n.(*ir.BinaryExpr)
		tab := s.expr(n.X)
		data := s.expr(n.Y)
		return s.newValue2(ssa.OpIMake, n.Type(), tab, data)

	case ir.OSLICEHEADER:
		n := n.(*ir.SliceHeaderExpr)
		p := s.expr(n.Ptr)
		l := s.expr(n.Len)
		c := s.expr(n.Cap)

                  ... }  ->  true if the value of label X is not one of \"a\", \"b\",
                  \"c\" \thas(label_name)  -> True if that label is present \t! expr
                  -> negation of expr \texpr && expr  -> Short-circuit and \texpr
                  || expr  -> Short-circuit or \t( expr ) -> parens for grouping \tall()
                  or the empty selector -> matches all endpoints. \n Label names are

pkg go/build/constraint, type AndExpr struct, X Expr
pkg go/build/constraint, type AndExpr struct, Y Expr
pkg go/build/constraint, type Expr interface, Eval(func(string) bool) bool
pkg go/build/constraint, type Expr interface, String() string
pkg go/build/constraint, type Expr interface, unexported methods
pkg go/build/constraint, type NotExpr struct
pkg go/build/constraint, type NotExpr struct, X Expr
pkg go/build/constraint, type OrExpr struct