If the following operations(s) can be safely performed unconditionally, the loop at line %d will be vectorized by adding a "%s ivdep" statement right before the loop: %s.
Add "!DIR$ IVDEP" before the specified loop.
This directive enables the vectorization of the loop at the specified line. You should ensure that any conditional divide, sqrt, and inverse sqrt operations will not alter the exception semantics expected by the program when they are performed unconditionally.
Consider the following:
subroutine foo(a, n)
integer n
real a(n)
do i=1,n
if (a(i) .gt. 0) then
a(i) = 1 / a(i)
endif
enddo
end
In this case, the compiler is unable to vectorize the loop since the condition "a(i) .gt. 0" may be guarding floating-point exceptions for the divide.
If you determine it is safe to do so, you can add the directive as follows:
subroutine foo(a, n)
integer n
real a(n)
!dir$ ivdep
do i=1,n
if (a(i) .gt. 0) then
a(i) = 1 / a(i)
endif
enddo
end
Make sure that the program operands have safe values for all iterations.
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