[Bug fortran/26682] New: gfortran fails with -fwhole-program optimization

[jjcogliati-r1 at yahoo dot com]

The following simple.f90 program:
PROGRAM hello_world
  PRINT *,"Hello, World!"
END PROGRAM hello_world

does not compile with the following arguments:
gfortran -fwhole-program -O2 -o simple simple.f90

~/gcc_install/lib/gcc/i686-pc-linux-gnu/4.1.0/../../../libgfortranbegin.a(fmain.o)(.text+0x23):
In function `main':
../../../gcc-4.1.0/libgfortran/fmain.c:18: undefined reference to `MAIN__'
collect2: ld returned 1 exit status

The program compiles fine with just -O2 or -fwhole-program and prints out the
expected Hello, World!

I think the problem roughly is that -fwhole-program combined with -O2 is
optimizing out the main function since it is not getting called internally.

I was unable to find in the documentation any method of forcing external
visiblity in a fortran 90 program.  There was also no mention of gfortran not
having -fwhole-program working in
http://gcc.gnu.org/onlinedocs/gcc-4.1.0/gcc/Optimize-Options.html


-- 
           Summary: gfortran fails with -fwhole-program optimization
           Product: gcc
           Version: 4.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: jjcogliati-r1 at yahoo dot com
 GCC build triplet: i686-pc-linux-gnu
  GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26682