Re: FAIL: gcc.c-torture/execute/950628-1.c execution, -O1

[Richard Henderson <rth at redhat dot com>]

On Fri, Jan 26, 2001 at 05:08:31PM -0500, Richard Kenner wrote:
>     I have a patch for objects_must_conflict_p to do that, but have been
>     waiting to see how the discussion resolves before doing anything with it.
> 
> I guess that's reasonable.

Ok.  I've now committed the following.

Bootstrapped on alphaev6-linux, and eyeballed the pa testcase
that started this thread.



r~



        * alias.c (objects_must_conflict_p): Read-only slots may not
        conflict despite having the same type.

Index: alias.c
===================================================================
RCS file: /cvs/gcc/egcs/gcc/alias.c,v
retrieving revision 1.114
diff -c -p -d -r1.114 alias.c
*** alias.c	2001/01/19 18:04:23	1.114
--- alias.c	2001/01/26 21:54:55
*************** int
*** 309,329 ****
  objects_must_conflict_p (t1, t2)
       tree t1, t2;
  {
    /* If they are the same type, they must conflict.  */
    if (t1 == t2
        /* Likewise if both are volatile.  */
        || (t1 != 0 && TYPE_VOLATILE (t1) && t2 != 0 && TYPE_VOLATILE (t2)))
      return 1;
  
!   /* We now know they are different types.  If one or both has readonly fields
!      or if one is readonly and the other not, they may not conflict.
!      Likewise if one is aggregate and the other is scalar.  */
!   if ((t1 != 0 && readonly_fields_p (t1))
!       || (t2 != 0 && readonly_fields_p (t2))
!       || ((t1 != 0 && TYPE_READONLY (t1))
! 	  != (t2 != 0 && TYPE_READONLY (t2)))
!       || ((t1 != 0 && AGGREGATE_TYPE_P (t1))
! 	  != (t2 != 0 && AGGREGATE_TYPE_P (t2))))
      return 0;
  
    /* Otherwise they conflict only if the alias sets conflict. */
--- 309,332 ----
  objects_must_conflict_p (t1, t2)
       tree t1, t2;
  {
+   /* If one or the other has readonly fields or is readonly,
+      then they may not conflict.  */
+   if ((t1 != 0 && readonly_fields_p (t1))
+       || (t2 != 0 && readonly_fields_p (t2))
+       || (t1 != 0 && TYPE_READONLY (t1))
+       || (t2 != 0 && TYPE_READONLY (t2)))
+     return 0;
+ 
    /* If they are the same type, they must conflict.  */
    if (t1 == t2
        /* Likewise if both are volatile.  */
        || (t1 != 0 && TYPE_VOLATILE (t1) && t2 != 0 && TYPE_VOLATILE (t2)))
      return 1;
  
!   /* If one is aggregate and the other is scalar then they may not
!      conflict.  */
!   if ((t1 != 0 && AGGREGATE_TYPE_P (t1))
!       != (t2 != 0 && AGGREGATE_TYPE_P (t2)))
      return 0;
  
    /* Otherwise they conflict only if the alias sets conflict. */