General Compiler Directive: Specifies the iterations (count) for a DO loop.
Syntax
cDEC$ LOOP COUNT (n1 [, n2] ...)
cDEC$ LOOP COUNT = n1 [, n2] ...
cDEC$ LOOP COUNT MAX(n1), MIN(n1), AVG(n1)
cDEC$ LOOP COUNT MAX=n1, MIN=n1, AVG=n1
c
Is one of the following: C (or c), !, or *. (See Syntax Rules for Compiler Directives.)
n1, n2
Is a non-negative integer constant.
Description
The value of the loop count affects heuristics used in software pipelining, vectorization, and loop-transformations.
| Description | |
|---|---|
| n1 [, n2] | Indicates that the next DO loop will iterate n1, n2, or some other number of times. |
| MAX, MIN, and AVG | Indicates that the next DO loop has the specified maximum, minimum, and average number (n1) of iterations. |
See Also
Rules for General Directives that Affect DO Loops, Optimizing Applications: Loop Count and Loop Distribution
Example
Consider the following:
cDEC$ LOOP COUNT (10000)
do i =1,m
b(i) = a(i) +1 ! This is likely to enable the loop to get software-pipelined
enddo
Note that you can specify more than one LOOP COUNT directive for a DO loop. For example, the following directives are valid:
!DEC$ LOOP COUNT (10, 20, 30)
!DEC$ LOOP COUNT MAX=100, MIN=3, AVG=17
DO
...