Code DO Loops for Efficiency

Minimize the arithmetic operations and other operations in a DO loop whenever possible. Moving unnecessary operations outside the loop will improve performance (for example, when the intermediate nonvarying values within the loop are not needed).

For more information:

• On loop optimizations, see Loop Transformations, and Controlling Loop Unrolling, and Software Pipelining (ia64 only).
• On the DO statement, see DO in the A-Z Summary in the Language Reference