Loop fusion is an optimization technique used in programming to combine multiple loops that iterate over the same data. By merging these loops, the number of iterations can be reduced, which can lead to improved performance. This is particularly beneficial in scenarios where the loops perform similar operations on the same data set. When loops are fused, the overhead of loop control is minimized, and data locality is enhanced. This means that the data is accessed more efficiently, which can improve cache performance. Overall, loop fusion helps in making code run faster and more efficiently, especially in high-performance computing scenarios.