Reliability decisions taken early in system design can bring significant benefits in terms of design quality. This paper presents a 0-1 integer linear programming (11,P) formulation for reliability-oriented high-level synthesis that addresses the soft error problem. The proposed approach tries to maximize reliability of the design while observing the bounds on area and performance, and makes use of our reliability characterization of hardware components such as adders and multipliers. We implemented the proposed approach, performed experiments with several example designs, and compared the results with those obtained by a prior proposal. Our results show that incorporating reliability as a first-class metric during high-level synthesis brings significant improvements on the overall design reliability.