Mechanisms for building approximate data dependences using a moving look-back window are provided. The mechanisms track dependence information for memory accesses over iterations of execution of a portion of code. The mechanisms receive a memory access of an iteration of the portion of code, the memory access having an address for access the memory and an access type indicating at least one of a read or a write access type. An entry in a moving look-back window data structure is generated corresponding to a memory location accessed by the memory access. The entry comprises at least an identification of the address, the access type, and an iteration number corresponding to the iteration of the memory access. The moving look-back window data structure is utilized to determine dependence information for memory accesses over a plurality of iterations of the portion of code.