What Is Loop Unrolling?
Loop unrolling is an optimization that duplicates the body of a loop so each iteration does the work of several, reducing the number of branch and counter updates. With fewer loop-control instructions and more independent operations exposed, the processor can overlap work more effectively. The trade-off is larger code, which can pressure the instruction cache.
Why it matters
Loop overhead can dominate tight loops with small bodies, and unrolling amortizes that cost across more useful work. It also gives the scheduler and vectorizer more material to optimize.
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