catastrophic error: **Internal compiler error: segmentation violation signal raised**

With
FFLAGS="-C -openmp"

# THIS DOES NOT MAKE COMPILATION ERROR.

  ifort -c $FFLAGS sub1.f90 sub2.f90

# THIS ALSO DOES NOT MAKE COMPILATION ERROR.

  cat   sub1.f90   sub2.f90   >   combined.f90
  ifort -c $FFLAGS   combined.f90

# THIS "DOES" MAKE COMPILATION ERROR.

  cat   sub2.f90   sub1.f90   >   combined-r.f90
  ifort -c $FFLAGS   combined-r.f90

The error message is:
combined-r.f90: catastrophic error: **Internal compiler error:
segmentation violation signal raised**
Please report this error along with the circumstances
in which it occurred in a Software Problem Report.  
Note: File and line given may not be explicit cause of this error.
compilation aborted for combined-r.f90 (code 1)

% ifort -v
ifort version 15.0.0

The Operating system, Linux (Cent-OS 7.0, or Fedora16 etc.)

You can do the above experiment by using my script "compile.sh".