UNROLL directive (The GNU Fortran Compiler) (original) (raw)

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6.2.2 UNROLL directive ¶

The syntax of the directive is

!GCC$ unroll N

You can use this directive to control how many times a loop should be unrolled. It must be placed immediately before a DO loop and applies only to the loop that follows. N is an integer constant specifying the unrolling factor. The values of 0 and 1 block any unrolling of the loop.

For DO CONCURRENT constructs the unrolling specification applies only to the first loop control variable.