What is Loop unrolling?
Replicating a loop body several times to reduce the number of iterations. It cuts branch and counter overhead and gives more freedom to reorder instructions, at the cost of larger code.
Field: Compilers
Loop unrolling in the explanations
Loop unrolling writes, say, four copies of the loop body and runs a quarter as many iterations.
What is the main effect of loop unrolling?A function usually consists of many basic blocks, and replicating a loop body is loop unrolling.
Which describes a basic block?Replicating a loop body is loop unrolling, and merging function calls is a different optimization.
Which is an example of constant folding by a compiler?
Questions that mention Loop unrolling (5)
- What is the main effect of loop unrolling?
- Which describes a basic block?
- Which is an example of constant folding by a compiler?
- In the loop above, which transformation applies strength reduction to the index computation i * 4?
- What is the main purpose of loop blocking (tiling), used for example in matrix multiplication?
Related terms
Basic block Control-flow graph Constant folding Strength reduction Loop blocking Abstract syntax tree Common subexpression elimination Function inlining Instruction scheduling Intermediate representation