Area and test time are two major overheads encountered during data path high level synthesis for BIST. This paper presents an approach to behavioral synthesis for loop-based BIST. By taking into account the requirements of the BIST scheme during behavioral synthesis processes, an area optimal BIST solution can be obtained. This approach is based on the use of test resources reusability that results in a fewer number of registers being modified to be test registers. This is achieved by incorporating self-testability constraints during register assignment operations. Experimental results on benchmarks are presented to demonstrate the effectiveness of the approach.