[Bug middle-end/42224] [4.5 Regression] 32bit pointers to 32bit pointers abort on 64bit VMS and S390X

["uweigand at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #3 from uweigand at gcc dot gnu dot org  2009-11-30 15:17 -------
OK, I've reproduced the problem.  It seems int_or_pointer_precision
is fundamentally wrong for pointers using a non-standard size
(i.e. pointer variables defined using a mode attribute).

The history of this is that there used to be code e.g. in
fold-const.c:fit_double_type that hard-coded a precision
of POINTER_SIZE for pointer types:

  if (POINTER_TYPE_P (type)
      || TREE_CODE (type) == OFFSET_TYPE)
    prec = POINTER_SIZE;
  else
    prec = TYPE_PRECISION (type);

This showed up as a bug in the presence of named-address-space
pointers of a different size than POINTER_SIZE.  The initial
thought to fix this as to just always use TYPE_PRECISION.

This turned out to break C++, as OFFSET_TYPEs were generated that
did not correctly set TYPE_PRECISION.   Mike fixed this, and added
the int_or_pointer_precision routine to verify that TYPE_PRECISION
of pointer and offset types is set correctly.

However, this now breaks on targets that allow pointers of different
size even for the same address space, because the verification in
int_or_pointer_precision fails.  I think we need to relax the check
to allow any "valid_pointer_mode" for the given address space as
mode of the pointer, as long as the precision matches the mode size
of that mode.

I'm testing a patch to that effect.


-- 

uweigand at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |uweigand at gcc dot gnu dot
                   |dot org                     |org
             Status|UNCONFIRMED                 |ASSIGNED
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2009-11-30 15:17:10
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42224