fwhole-program issue

[Tobias Burnus]

Hi,

Manfred Schwarb wrote:
> I'm somewhat puzzled: for me the dead simple program
> # cat wholeprogram1.f
>       subroutine wholeprogram1
>       print*,"wholeprogram1"
>       end
> # cat wholeprogram2.f
>       program wholeprogram2
>       call wholeprogram1
>       end
> does not compile with -fwhole-program

That's not surprising:
    gfortran -fwhole-program -c wholeprogram1.f
can optimize "wholeprogram1" away as it is not called in that file.

Recall that -fwhole-program work per translation/compilation unit (TU, 
i.e. per file), which is also indicated in the manual:

"-fwhole-program
            Assume that the current compilation unit represents the 
whole program being compiled. [...]"

Thus, -fwhole-program should either only be used if one has only a 
single file (or for the file which contains only the main program). Or 
together with link-time optimization (LTO), enabled by "-flto".

Thus, you should add "-flto".

Tobias