case ir.OLITERAL, ir.ONIL, ir.OMETHEXPR, ir.ONEW:
			return
		case ir.ONAME:
			arg := arg.(*ir.Name)
			if arg.Class == ir.PFUNC {
				return // reference to global function
			}
		case ir.OADDR:
			arg := arg.(*ir.AddrExpr)
			if arg.X.Op() == ir.OLINKSYMOFFSET {
				return // address of global symbol
			}

		case ir.OCONVNOP:
			arg := arg.(*ir.ConvExpr)

	//
	// TODO(mdempsky): Note that OuterValue unwraps OCONVNOPs, but
	// IsAddressable does not. It should be possible to skip copying for
	// at least some of these OCONVNOPs (e.g., reinsert them after the
	// OADDR operation), but at least walkCompare needs to be fixed to
	// support that (see trybot failures on go.dev/cl/541715, PS1).
	if ir.IsAddressable(n) {
		if name, ok := ir.OuterValue(n).(*ir.Name); ok && name.Op() == ir.ONAME {

		n := n.(*ir.UnaryExpr)
		a := s.expr(n.X)
		return s.newValue1(s.ssaOp(n.Op(), n.X.Type()), n.Type(), a)
	case ir.OPLUS:
		n := n.(*ir.UnaryExpr)
		return s.expr(n.X)

	case ir.OADDR:
		n := n.(*ir.AddrExpr)
		return s.addr(n.X)

	case ir.ORESULT:
		n := n.(*ir.ResultExpr)