The LOOP COUNT(n) directive indicates the loop count is likely to be n, where n is an integer constant.
The value of loop count affects heuristics used in software pipelining and data prefetch.
Example 1 |
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!DEC$ LOOP COUNT (10000) do i =1,m b(i) = a(i) +1 ! This is likely to enable ! the loop to get software- ! pipelined enddo |
For more details on this directive, see "Directive Enhanced Compilation", section "General Directives", in the Intel® Fortran Language Reference.
The DISTRIBUTE POINT directive indicates a preference for performing loop distribution.
Loop distribution may cause large loops be distributed into smaller ones. This may enable more loops to get software-pipelined.
If the directive is placed inside a loop, the distribution is performed after the directive and any loop-carried dependency is ignored.
If the directive is placed before a loop, the compiler will determine where to distribute and data dependency is observed. Multiple distribute directives are supported if they are placed inside the loop. When they are placed inside the loop, they cannot be put inside an IF statement.
Example 2: Example of distribute point Directive |
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!DEC$ DISTRIBUTE POINT do i =1, m b(i) = a(i) +1 .... c(i) = a(i) + b(i) ! Compiler will decide where ! to distribute ! Data dependency is observed .... d(i) = c(i) + 1 enddo
do i =1, m b(i) = a(i) +1 .... !DEC$ DISTRIBUTE POINT call sub(a, n) ! Distribution will start here, ! ignoring all loop-carried ! dependency c(i) = a(i) + b(i) .... d(i) = c(i) + 1 enddo |