Intel Fortran Language Reference - NCI National Facility

14 Intel Fortran Language Reference
4. Add the results from steps 2 and 3.
5. Store the results from step 4 into the location indicated by A(INDARR(I)) from step 1.
IVDEP directs the compiler to initially assume that when steps 1 and 5 access a common memory
location, step 1 always accesses the location first because step 1 occurs earlier in the execution
sequence. This approach lets the compiler reorder instructions, as long as it chooses an instruction
schedule that maintains the relative order of the array references.
See Also
“Rules for General Directives that Affect DO Loops”
LOOP COUNT Directive
The LOOP COUNT directive specifies the loop count for a DO loop; this assists the optimizer
This directive takes the following form:
cDEC$ LOOP COUNT (n)
–or–
cDEC$ LOOP COUNT = n
c
Is one of the following: C (or c), !, or * (see “Syntax Rules for Compiler Directives”).
n
Is an integer constant.
Rules and Behavior
The value of the loop count affects heuristics used in software pipelining, vectorization, and
loop-transformations.
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
See Also
“Rules for General Directives that Affect DO Loops”
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