[Bug tree-optimization/30562] [4.3 Regression] remove unused variable is removing a referenced variable (in STORED_SYMS or LOADED_SYMS)

["dnovillo at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org>]

------- Comment #5 from dnovillo at gcc dot gnu dot org  2007-02-07 23:33 -------

I cannot reproduce this bug with mainline as of 2007-02-06.  The bug is still
latent though, so I will commit a variant of this patch to fix it. 
Essentially, we should leave every TREE_ADDRESSABLE variable alone so that it
can be removed by a subsequent may_alias pass:

Index: tree-ssa-live.c
===================================================================
--- tree-ssa-live.c     (revision 121699)
+++ tree-ssa-live.c     (working copy)
@@ -502,18 +502,20 @@
       cell = &TREE_CHAIN (*cell);
     }

-  /* Remove unused variables from REFERENCED_VARs.  As an special exception
-     keep the variables that are believed to be aliased.  Those can't be
-     easily removed from the alias sets and and operand caches.
-     They will be removed shortly after next may_alias pass is performed.  */
+  /* Remove unused variables from REFERENCED_VARs.  As a special
+     exception keep the variables that are believed to be aliased.
+     Those can't be easily removed from the alias sets and operand
+     caches.  They will be removed shortly after the next may_alias
+     pass is performed.  */
   FOR_EACH_REFERENCED_VAR (t, rvi)
     if (!is_global_var (t)
        && !MTAG_P (t)
        && TREE_CODE (t) != PARM_DECL
        && TREE_CODE (t) != RESULT_DECL
        && !(ann = var_ann (t))->used
-       && !ann->is_aliased && !is_call_clobbered (t) && !ann->symbol_mem_tag)
-        remove_referenced_var (t);
+       && !ann->symbol_mem_tag
+       && !TREE_ADDRESSABLE (t))
+      remove_referenced_var (t);
 }


-- 

dnovillo at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |WORKSFORME


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30562