tree-pass.h (pass_eliminate_useless_stores): Remove.

2005-12-23  Daniel Berlin  <dberlin@dberlin.org>

	* tree-pass.h (pass_eliminate_useless_stores): Remove.
	* tree-ssa-pre.c (is_copy_stmt): Ditto.
	(follow_copies_till_vuse): Ditto.
	(do_eustore): Ditto.
	(gate_eustores): Ditto.
	(pass_eliminate_useless_stores): Ditto.
	* passes.c (init_optimization_passes): Ditto.

From-SVN: r109034

gcc/ChangeLog

+2005-12-23  Daniel Berlin  <dberlin@dberlin.org>
+
+	* tree-pass.h (pass_eliminate_useless_stores): Remove.
+	* tree-ssa-pre.c (is_copy_stmt): Ditto.
+	(follow_copies_till_vuse): Ditto.
+	(do_eustore): Ditto.
+	(gate_eustores): Ditto.
+	(pass_eliminate_useless_stores): Ditto.
+	* passes.c (init_optimization_passes): Ditto.
+
 2005-12-23  Paolo Bonzini  <bonzini@gnu.org>
 
         * combine.c (simplify_shift_const): Fix typo.  Use, whenever

gcc/passes.c

@@ -498,7 +498,6 @@ init_optimization_passes (void)
   NEXT_PASS (pass_return_slot);
   NEXT_PASS (pass_rename_ssa_copies);
   NEXT_PASS (pass_early_warn_uninitialized);
-  NEXT_PASS (pass_eliminate_useless_stores);
 
   /* Initial scalar cleanups.  */
   NEXT_PASS (pass_ccp);

gcc/testsuite/gcc.dg/tree-ssa/ssa-eustores.c

-/* { dg-do compile } */ 
-/* { dg-options "-O2 -fdump-tree-eustores-all" } */
-static int a;
-int foo()
-{
-  int alocal;
-  int b;
-  alocal = a;
-  b = alocal;
-  a = b;
-}
-/* We should eliminate the store back to a.  */
-/* { dg-final { scan-tree-dump-times "Eliminating useless store" 1 "eustores"} } */
-/* { dg-final { cleanup-tree-dump "eustores" } } */

gcc/tree-pass.h

@@ -285,7 +285,6 @@ extern struct tree_opt_pass pass_uncprop;
 extern struct tree_opt_pass pass_return_slot;
 extern struct tree_opt_pass pass_reassoc;
 extern struct tree_opt_pass pass_rebuild_cgraph_edges;
-extern struct tree_opt_pass pass_eliminate_useless_stores;
 
 /* IPA Passes */
 extern struct tree_opt_pass pass_ipa_cp;

gcc/tree-ssa-pre.c

@@ -2928,135 +2928,3 @@ struct tree_opt_pass pass_fre =
   0					/* letter */
 };
 
-/* Return true if T is a copy statement between two ssa names.  */
-
-static bool
-is_copy_stmt (tree t)
-{  
-  if (!t || TREE_CODE (t) != MODIFY_EXPR)
-    return false;
-  if (TREE_CODE (TREE_OPERAND (t, 0)) == SSA_NAME 
-      && TREE_CODE (TREE_OPERAND (t, 1)) == SSA_NAME)
-    return true;
-  return false;
-}
-
-/* Starting from START, walk copy statements till we hit a statement with a
-   VUSE or a non-copy statement.  */
-
-static tree 
-follow_copies_till_vuse (tree start)
-{
-  if (is_copy_stmt (start) && ZERO_SSA_OPERANDS (start, SSA_OP_VIRTUAL_USES))
-    {
-      tree rhs, defstmt;
-
-      rhs = TREE_OPERAND (start, 1);
-      defstmt = SSA_NAME_DEF_STMT (rhs);
-      return follow_copies_till_vuse (defstmt);
-    }
-  return start;
-}
-
-/* Gate and execute functions for eliminate useless stores.	
-   The goal here is to recognize the pattern *x = ... *x, and eliminate the
-   store because the value hasn't changed.  Store copy/const prop won't
-   do this because making *more* loads (IE propagating *x) is not a win, so it
-   ignores them.  
-   This pass is currently geared completely towards static variable store
-   elimination.  */
-
-static void
-do_eustores (void)
-{
-  basic_block bb;
-  /* For each basic block
-       For each statement (STMT) in the block
-         if STMT is a stores of the pattern *x = y
-           follow the chain of definitions for y, until we hit a non-copy
-	   statement or a statement with a vuse. 
-	     if the statement we arrive at is a vuse of the operand we killed,
-	     accessed through the same memory operation, then we have a
-	     useless store (because it is *x = ... = *x).  */
-	  
-  FOR_EACH_BB (bb)
-    {
-      block_stmt_iterator bsi;
-
-      for (bsi = bsi_start (bb);
-	   !bsi_end_p (bsi);)
-	{
-	  tree stmt = bsi_stmt (bsi);
-	  tree startat;
-	  tree kill;	  
-	  tree found;
-	  	  
-	  if (NUM_SSA_OPERANDS (stmt, SSA_OP_VMUSTDEF) != 1
-	      || TREE_CODE (stmt) != MODIFY_EXPR
-	      || TREE_CODE (TREE_OPERAND (stmt, 1)) != SSA_NAME)
-	    {
-	      bsi_next (&bsi);
-	      continue;
-	    }
-
-	  kill = MUSTDEF_KILL (MUSTDEF_OPS (stmt)); 
-	  startat = TREE_OPERAND (stmt, 1);
-	  startat = SSA_NAME_DEF_STMT (startat);
-	  found = follow_copies_till_vuse (startat);
-
-	  if (found && TREE_CODE (found) == MODIFY_EXPR)
-	    {	   
-
-	      /* We want exactly one virtual use, and it should match up with
-		 the use being killed.  */
-
-	      if (NUM_SSA_OPERANDS (found, SSA_OP_VUSE) != 1
-		  || VUSE_OP (VUSE_OPS (found)) != kill
-		  || !DECL_P (TREE_OPERAND (stmt, 0))
-		  || !operand_equal_p (TREE_OPERAND (found, 1), 
-				       TREE_OPERAND (stmt, 0), 0))
-		{
-		  bsi_next (&bsi);
-		  continue;
-		}
-
-	      if (dump_file)
-		{
-		  fprintf (dump_file, "Eliminating useless store ");
-		  print_generic_stmt (dump_file, stmt, 0);
-		}
-	      mark_sym_for_renaming (TREE_OPERAND (stmt, 0));
-	      bsi_remove (&bsi);
-	    }
-	  else
-	    {
-	      bsi_next (&bsi);
-	      continue;
-	    }
-	}
-    }
-}
-
-static bool
-gate_eustores(void)
-{
-  return flag_unit_at_a_time != 0;
-}
-
-struct tree_opt_pass pass_eliminate_useless_stores =
-{
-  "eustores",				/* name */
-  gate_eustores,				/* gate */
-  do_eustores,				/* execute */
-  NULL,					/* sub */
-  NULL,					/* next */
-  0,					/* static_pass_number */
-  0,				/* tv_id */
-  PROP_cfg | PROP_ssa | PROP_alias,	/* properties_required */
-  0,					/* properties_provided */
-  0,					/* properties_destroyed */
-  0,					/* todo_flags_start */
-  TODO_update_ssa | TODO_dump_func 
-  | TODO_ggc_collect | TODO_verify_ssa, /* todo_flags_finish */
-  0					/* letter */
-};