[Bug fortran/110360] ABI issue with character,value dummy argument

[dje at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110360

--- Comment #32 from David Edelsohn <dje at gcc dot gnu.org> ---
i think that I see part of the difference.  The 005t.original dump shows
(intermingled with sources)

!   call val  ("B","B")
  val (&"B"[1]{lb: 1 sz: 1}, "B", 1, 1);
!   call val  ("A",char(65))
  val (&"A"[1]{lb: 1 sz: 1}, "A", 1, 1);
!   call val  ("A",char(a))
  {
    character(kind=1) char.6;

    char.6 = (character(kind=1)) a;
    val (&"A"[1]{lb: 1 sz: 1}, char.6, 1, 1);
  }
!  call val  ("A",mychar(65))

  {
    static integer(kind=4) C.2654 = 65;
    character(kind=1) str.7[1];

    mychar ((character(kind=1)[1:1] *) &str.7, 1, &C.2654);
    val (&"A"[1]{lb: 1 sz: 1}, str.7[0], 1, 1);
  }
!  call val  ("A",mychar(a))
  {
    character(kind=1) str.8[1];

    mychar ((character(kind=1)[1:1] *) &str.8, 1, &a);
    val (&"A"[1]{lb: 1 sz: 1}, str.8[0], 1, 1);
  }

char(65) is folded by the FORTRAN front-end to "A", so it is passed in the same
manner that elicits the shift.  The rest of the calls pass 65.  The string is
left-shifted and the number is right-shifted.  GFORTRAN seems to assume that
passing a STRING by value will be padded the same as a number or character,
which isn't accurate.

I'm leaning back to big-endian vs little-endian, and not a struct issue.  A
little-endian STRING will start at the lowest address and a big-endian STRING
will start at the highest address.