Issue: User function call(s) present

Recommendation: Enable inline expansion

Inlining of user-defined functions is disabled by compiler option. To fix: When using the Ob or inline-level compiler option to control inline expansion, replace the 0 argument with the 1 argument to enable inlining when an inline keyword or attribute is specified or the 2 argument to enable inlining of any function at compiler discretion.

Read More:

• Vectorization Resources for Intel® Advisor Users

Recommendation: Vectorize user function(s) inside loop

Some user-defined function(s) are not vectorized or inlined by the compiler. To fix: Do one of the following:

• Enforce vectorization of the source loop by means of SIMD instructions and/or create a SIMD version of the function(s) using a directive:

  Target	Directive
  Source loop	!DIR$ SIMD or !$OMP SIMD
  Inner function definition or declaration	!$OMP DECLARE SIMD

• If using the Ob or inline-level compiler option to control inline expansion with the 1 argument, use an inline keyword to enable inlining or replace the 1 argument with 2 to enable inlining of any function at compiler discretion.

Example:

real function f (x)
!DIR$ OMP DECLARE SIMD
    real, intent(in), value  :: x
    f= x + 1
  end function f

!DIR$ OMP SIMD
  do k = 1, N
     a(k) = f(k)
  enddo

Read More:

• Getting Started with Intel Compiler Pragmas and Directives and Vectorization Resources for Intel® Advisor Users

Recommendation: Convert to Fortran SIMD-enabled functions

Passing an array/array section to an ELEMENTAL function/subroutine is creating a dependency that prevents vectorization. To fix:

• Enforce vectorization of the source loop using SIMD instructions and/or create a SIMD version of the function(s) using a directive:

  Target	Directive
  Source loop	!DIR$ SIMD or !$OMP SIMD
  Inner function definition or declaration	!$OMP DECLARE SIMD

• Call from a DO loop.

Example:

Original code:

elemental subroutine callee(t,q,r) 
    real, intent(in) :: t, q 
    real, intent(out) :: r 
    r = t + q 
  end subroutine callee  
  ... 
  do k = 1,nlev 
    call callee(a(:,k), b(:,k), c(:,k))
  end do 
  ... 

Revised code:

 subroutine callee(t,q,r) 
  !$OMP DECLARE SIMD(callee) 
    real, intent(in) :: t, q 
    real, intent(out) :: r 
    r = t + q 
  end subroutine callee  
  ... 
  do k = 1,nlev 
    !$OMP SIMD 
    do i = 1,n 
      call callee(a(i,k), b(i,k), c(i,k)) 
    end do 
  end do 
  ... 

Read More:

• Explicit Vector Programming in Fortran, Getting Started with Intel Compiler Pragmas and Directives and Vectorization Resources for Intel® Advisor Users