// Note: we store the variable number in the phi's AuxInt field. Used temporarily by phi building.
				if var_.Op() == ir.ONAME {
					s.s.addNamedValue(var_.(*ir.Name), v)
				}
				for range c.Preds {
					v.AddArg(s.placeholder) // Actual args will be filled in by resolveFwdRefs.
				}
				if debugPhi {
					fmt.Printf("new phi for var%d in %s: %s\n", n, c, v)