A method for implementing shadow versioning to improve data dependence analysis for instruction scheduling in compiling code, and to identify loops within the code to be compiled, for each loop initializing a dependence a matrix, for each loop shadow identifying symbols that are accessed by the loop, examining dependencies, storing, comparing and classifying the dependence vectors, generating new shadow symbols, replacing the old shadow symbols with the new shadow symbols, generating alias relationships between the newly created shadow symbols, scheduling instructions and compiling the code.