[Bug fortran/80945] Invalid code with allocatable character array in READ/WRITE statement

[tkoenig at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80945

--- Comment #7 from Thomas Koenig <tkoenig at gcc dot gnu.org> ---
Still fails with current trunk.

Code from comment#1, somewhat simplified:

program main
    implicit none
    integer:: i
    integer, parameter:: N = 10
    character(len=:), dimension(:),allocatable:: ca
    allocate(character(len=N):: ca(3))
    ca(1) = "foo"
    ca(2) = "bar"
    ca(3) = "xyzzy"
    write (*, '(3A5)') ca(1:3)
end program

This yields on gcc110:

foo  foo  foo  

Looking at the tree dump, we see

MAIN__ ()
{
  integer(kind=8) .ca;
  struct array01_unknown ca;
  bitsizetype D.2078;
  sizetype D.2079;

  D.2078 = (bitsizetype) (sizetype) NON_LVALUE_EXPR <.ca> * 8;
  D.2079 = (sizetype) NON_LVALUE_EXPR <.ca>;

and later

  {
    integer(kind=4) overflow.0;

    .ca = 10;
    ca.dtype = {.elem_len=(unsigned long) SAVE_EXPR <(sizetype) NON_LVALUE_EXPR
<.ca>>, .rank=1, .type=6};

...

    _gfortran_st_write (&dt_parm.1);
      {
        struct array01_unknown parm.2;

        parm.2.dtype = {.elem_len=(unsigned long) SAVE_EXPR <D.2079>, .rank=1,
.type=6};
        parm.2.dim[0].lbound = 1;
        parm.2.dim[0].ubound = 3;
        parm.2.dim[0].stride = 1;
        parm.2.data = (void *) &(*(character(kind=1)[0:][1:.ca] * restrict)
ca.data)[1 - ca.dim[0].lbound];
        parm.2.offset = ca.offset;
        _gfortran_transfer_array_write (&dt_parm.1, &parm.2, 1, .ca);

so the dtype gets its elem_len from the uninitialized copy of .ca
instead of the correctly initialized value later.

Paul, does this ring any bells?