Visible to Intel only — GUID: GUID-10B6E99A-3160-4CF8-BDDD-1D43FE52C2AE
Visible to Intel only — GUID: GUID-10B6E99A-3160-4CF8-BDDD-1D43FE52C2AE
GAP Message (Diagnostic ID 30506)
Message
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.
Advice
Add "!DIR$ IVDEP" before the specified loop.
This directive enables the vectorization of the loop at the specified line. Insure that any conditional divide, sqrt, and inverse sqrt operations will not alter the exception semantics expected by the program when they are performed unconditionally.
Example
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
Verify
Confirm that the program operands have safe values for all iterations.