Function inlining

[MichaelSt98]

Currently only (single-line) elemental functions are supported.

Currently, this

  elemental function multiply(a, b)
    real(kind=real64) :: multiply
    real(kind=real64), intent(in) :: a, b

    multiply = a * b
  end function multiply

can be inlined correctly. However, something like

  elemental function multiply(a, b)
    real(kind=real64) :: multiply
    real(kind=real64), intent(in) :: a, b
    real(kind=real64) :: temp

    temp = a * b
    multiply = temp
  end function multiply

will be inlined but not correctly! (since only multiply = temp gets inlined).

Further, inlining of member functions is not supported as well as functions that have return value based on a conditional (assignment)

  elemental function multiply_if(a, b)
    real(kind=real64) :: multiply_if
    real(kind=real64), intent(in) :: a, b

    if (a .gt. b) then
      multiply_if = a * b
    else 
      multiply_if = a * a
    endif
  end function multiply_if