[Bug target/31319] Make big alignment for structs/arrays configurable

["vda dot linux at googlemail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #3 from vda dot linux at googlemail dot com  2007-03-23 12:00 -------
You are right, in current svn it is fixed.
BTW I think I see a bug created by this change: with -Os x86_86 ABI will be
violated - arrays larger than 16 bytes will still be aligned only to 4 bytes
because if's are in wrong order. shouldn't they be swapped?

(nitpicking: if comment is true, then second if should check that object is an
*array*, not a *struct*, but it doesn't seem to do it)

  int max_align = optimize_size ? BITS_PER_WORD : 256;

  if (AGGREGATE_TYPE_P (type)
      && TYPE_SIZE (type)
      && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
      && (TREE_INT_CST_LOW (TYPE_SIZE (type)) >= (unsigned) max_align
          || TREE_INT_CST_HIGH (TYPE_SIZE (type)))
      && align < max_align)
    align = max_align;

  /* x86-64 ABI requires arrays greater than 16 bytes to be aligned
     to 16byte boundary.  */
  if (TARGET_64BIT)
    {
      if (AGGREGATE_TYPE_P (type)
           && TYPE_SIZE (type)
           && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
           && (TREE_INT_CST_LOW (TYPE_SIZE (type)) >= 128
               || TREE_INT_CST_HIGH (TYPE_SIZE (type))) && align < 128)
        return 128;
    }


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31319