[Bug tree-optimization/16913] [4.0 Regression] restrict does not make a different

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-11-22 07:12 -------
The way to fix this is before going out of SSA to have another HOST_WIDE_INT in INDIRECT_REF to say 
the aliasing set for that tree.
And also add this patch which looks at the use defs:
Index: alias.c
===============================================================
====
RCS file: /cvs/gcc/gcc/gcc/alias.c,v
retrieving revision 1.246
diff -u -p -r1.246 alias.c
--- alias.c     11 Nov 2004 23:08:55 -0000      1.246
+++ alias.c     22 Nov 2004 07:08:29 -0000
@@ -347,6 +347,15 @@ find_base_decl (tree t)
 
   if (t == 0 || t == error_mark_node || ! POINTER_TYPE_P (TREE_TYPE (t)))
     return 0;
+    
+  if (TREE_CODE (t) == SSA_NAME)
+    {
+      d0 = SSA_NAME_DEF_STMT (t);
+      if (TREE_CODE (d0) == MODIFY_EXPR)
+       return find_base_decl (TREE_OPERAND (d0, 1));
+      else
+        return 0;
+    }
 
   /* If this is a declaration, return it.  */
   if (DECL_P (t))

Currently if I use the following optimizations I get the optimization:
-fno-tree-pre -fno-tree-loop-im -fno-tree-dominator-opts -fno-ivopts
The reason why PRE and loop-im is needed is because we would pull out the b[j] out of the loop.
the reason why dominator-opts is need is because we would combine b[j] for the INDIRECT's.
The reason why -fno-ivopts is needed is because we would change a[i] into *iv.opt


-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|2004-10-08 14:53:59         |2004-11-22 07:12:49
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16913