Fix PR43464: copyprop should maintain loop close phi nodes with multiple arguments.

2010-03-30  Richard Guenther  <rguenther@suse.de>
	    Zdenek Dvorak  <ook@ucw.cz>
	    Sebastian Pop  <sebastian.pop@amd.com>

	PR middle-end/43464
	* tree-ssa-copy.c (init_copy_prop): Handle loop close phi nodes
	with multiple arguments.
	(execute_copy_prop): Remove call to rewrite_into_loop_closed_ssa.

Co-Authored-By: Sebastian Pop <sebastian.pop@amd.com>
Co-Authored-By: Zdenek Dvorak <ook@ucw.cz>

From-SVN: r157889

gcc/ChangeLog.graphite

+2010-03-30  Richard Guenther  <rguenther@suse.de>
+	    Zdenek Dvorak  <ook@ucw.cz>
+	    Sebastian Pop  <sebastian.pop@amd.com>
+
+	PR middle-end/43464
+	* tree-ssa-copy.c (init_copy_prop): Handle loop close phi nodes
+	with multiple arguments.
+	(execute_copy_prop): Remove call to rewrite_into_loop_closed_ssa.
+
 2010-03-23  Sebastian Pop  <sebastian.pop@amd.com>
 
 	* graphite-dependences.c (print_pddr): Call print_pdr with an

gcc/tree-ssa-copy.c

@@ -749,6 +749,7 @@ init_copy_prop (void)
     {
       gimple_stmt_iterator si;
       int depth = bb->loop_depth;
+      bool loop_exit_p = false;
 
       for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
 	{
@@ -786,6 +787,18 @@ init_copy_prop (void)
 	      cached_last_copy_of[SSA_NAME_VERSION (def)] = def;
 	}
 
+      /* In loop-closed SSA form do not copy-propagate through
+	 PHI nodes in blocks with a loop exit edge predecessor.  */
+      if (current_loops
+	  && loops_state_satisfies_p (LOOP_CLOSED_SSA))
+	{
+	  edge_iterator ei;
+	  edge e;
+	  FOR_EACH_EDGE (e, ei, bb->preds)
+	    if (loop_exit_edge_p (e->src->loop_father, e))
+	      loop_exit_p = true;
+	}
+
       for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si))
 	{
           gimple phi = gsi_stmt (si);
@@ -793,12 +806,7 @@ init_copy_prop (void)
 
 	  def = gimple_phi_result (phi);
 	  if (!is_gimple_reg (def)
-	      /* In loop-closed SSA form do not copy-propagate through
-	         PHI nodes.  Technically this is only needed for loop
-		 exit PHIs, but this is difficult to query.  */
-	      || (current_loops
-		  && gimple_phi_num_args (phi) == 1
-		  && loops_state_satisfies_p (LOOP_CLOSED_SSA)))
+	      || loop_exit_p)
             prop_set_simulate_again (phi, false);
 	  else
             prop_set_simulate_again (phi, true);