[Bug fortran/71204] New: ICE with -O0 in expand_expr_real_1, at expr.c:9651

[gerhard.steinmetz.fort...@t-online.de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71204

            Bug ID: 71204
           Summary: ICE with -O0 in expand_expr_real_1, at expr.c:9651
           Product: gcc
           Version: 6.1.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gerhard.steinmetz.fort...@t-online.de
  Target Milestone: ---

Full reduction and simplification from a production code base
results in the following reproducer, aborting at -O0 :


$ cat z1.f90
module m
   character(10), allocatable :: z(:)
end module

subroutine s1
   use m
   z(2) = z(1)
end

subroutine s2
   use m
   z(2) = z(1)
end


$ gfortran-6 --version
GNU Fortran (SUSE Linux) 6.1.1 20160502 [gcc-6-branch revision 235698]

$ gfortran-6 -O2 -c z1.f90
$ gfortran-6 -O1 -c z1.f90
$ gfortran-6 -O0 -c z1.f90
z1.f90:12:0:

    z(2) = z(1)

internal compiler error: in expand_expr_real_1, at expr.c:9651