[Bug fortran/30409] [fortran] missed optimization with pure function arguments

[kargl at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=30409

--- Comment #12 from kargl at gcc dot gnu.org ---
(In reply to anlauf from comment #11)
> (In reply to kargl from comment #10)
> > (In reply to anlauf from comment #8)
> 
> > which is equivalent to 
> > 
> >    tmp = 1 / y
> >    do i = 1, n
> >       ... = expression1(..., tmp)
> >    end do
> 
> No.  Strictly speaking, it is only equivalent to:
> 
>     if (n > 0) tmp = 1 / y
>     do i = 1, n
>        ... = expression1(..., tmp)
>     end do

Ah, yes, I missed the possibility that the loop may not loop at all.