[Bug middle-end/63793] -mcmodel=medium in gfortran on x86_64 emits references that are RIP relative (instead of using the GOT)

[howarth at bromo dot med.uc.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63793

--- Comment #8 from howarth at bromo dot med.uc.edu ---
It appears the two instances of the use of HAVE_AS_GOTOFF_IN_DATA are in
gcc/config/i386/i386.c

void
ix86_output_addr_diff_elt (FILE *file, int value, int rel)
{
  const char *directive = ASM_LONG;

#ifdef ASM_QUAD
  if (TARGET_64BIT && CASE_VECTOR_MODE == DImode)
    directive = ASM_QUAD;
#else
  gcc_assert (!TARGET_64BIT);
#endif
  /* We can't use @GOTOFF for text labels on VxWorks; see gotoff_operand.  */
  if (TARGET_64BIT || TARGET_VXWORKS_RTP)
    fprintf (file, "%s%s%d-%s%d\n",
             directive, LPREFIX, value, LPREFIX, rel);
  else if (HAVE_AS_GOTOFF_IN_DATA)
    fprintf (file, ASM_LONG "%s%d@GOTOFF\n", LPREFIX, value);
#if TARGET_MACHO
  else if (TARGET_MACHO)
    {
      fprintf (file, ASM_LONG "%s%d-", LPREFIX, value);
      machopic_output_function_base_name (file);
      putc ('\n', file);
    }
#endif
  else
    asm_fprintf (file, ASM_LONG "%U%s+[.-%s%d]\n",
                 GOT_SYMBOL_NAME, LPREFIX, value);
}
^L
/* Generate either "mov $0, reg" or "xor reg, reg", as appropriate
   for the target.  */

and in gcc/config/i386/i386.md

(define_expand "tablejump"
  [(parallel [(set (pc) (match_operand 0 "indirect_branch_operand"))
              (use (label_ref (match_operand 1)))])]
  ""
{
  /* In PIC mode, the table entries are stored GOT (32-bit) or PC (64-bit)
     relative.  Convert the relative address to an absolute address.  */
  if (flag_pic)
    {
      rtx op0, op1;
      enum rtx_code code;

      /* We can't use @GOTOFF for text labels on VxWorks;
         see gotoff_operand.  */
      if (TARGET_64BIT || TARGET_VXWORKS_RTP)
        {
          code = PLUS;
          op0 = operands[0];
          op1 = gen_rtx_LABEL_REF (Pmode, operands[1]);
        }
      else if (TARGET_MACHO || HAVE_AS_GOTOFF_IN_DATA)
        {
          code = PLUS;
          op0 = operands[0];
          op1 = pic_offset_table_rtx;
        }
      else
        {
          code = MINUS;
          op0 = pic_offset_table_rtx;
          op1 = operands[0];
        }

      operands[0] = expand_simple_binop (Pmode, code, op0, op1, NULL_RTX, 0,
                                         OPTAB_DIRECT);
    }