re PR debug/44205 (Wrong .debug_line for -O0 -g)

	PR debug/44205
	* tree-cfgcleanup.c (tree_forwarder_block_p): Return false if
	at -O0 goto_locus of any of the incoming edges differs from
	goto_locus of outgoing edge, or gimple_location of any of the
	labels differs.

From-SVN: r159652

gcc/ChangeLog

+2010-05-21  Jakub Jelinek  <jakub@redhat.com>
+
+	PR debug/44205
+	* tree-cfgcleanup.c (tree_forwarder_block_p): Return false if
+	at -O0 goto_locus of any of the incoming edges differs from
+	goto_locus of outgoing edge, or gimple_location of any of the
+	labels differs.
+
 2009-09-14  Vladimir Makarov <vmakarov@redhat.com>
 
 	* ira.c (ira_non_ordered_class_hard_regs): Define.

gcc/tree-cfgcleanup.c

@@ -267,6 +267,7 @@ static bool
 tree_forwarder_block_p (basic_block bb, bool phi_wanted)
 {
   gimple_stmt_iterator gsi;
+  location_t locus;
 
   /* BB must have a single outgoing edge.  */
   if (single_succ_p (bb) != 1
@@ -285,6 +286,8 @@ tree_forwarder_block_p (basic_block bb, bool phi_wanted)
   gcc_assert (bb != ENTRY_BLOCK_PTR);
 #endif
 
+  locus = single_succ_edge (bb)->goto_locus;
+
   /* There should not be an edge coming from entry, or an EH edge.  */
   {
     edge_iterator ei;
@@ -293,6 +296,10 @@ tree_forwarder_block_p (basic_block bb, bool phi_wanted)
     FOR_EACH_EDGE (e, ei, bb->preds)
       if (e->src == ENTRY_BLOCK_PTR || (e->flags & EDGE_EH))
 	return false;
+      /* If goto_locus of any of the edges differs, prevent removing
+	 the forwarder block for -O0.  */
+      else if (optimize == 0 && e->goto_locus != locus)
+	return false;
   }
 
   /* Now walk through the statements backward.  We can ignore labels,
@@ -306,6 +313,8 @@ tree_forwarder_block_p (basic_block bb, bool phi_wanted)
 	case GIMPLE_LABEL:
 	  if (DECL_NONLOCAL (gimple_label_label (stmt)))
 	    return false;
+	  if (optimize == 0 && gimple_location (stmt) != locus)
+	    return false;
 	  break;
 
 	  /* ??? For now, hope there's a corresponding debug
@@ -608,11 +617,7 @@ cleanup_tree_cfg_bb (basic_block bb)
 
   retval = cleanup_control_flow_bb (bb);
 
-  /* Forwarder blocks can carry line number information which is
-     useful when debugging, so we only clean them up when
-     optimizing.  */
-  if (optimize > 0
-      && tree_forwarder_block_p (bb, false)
+  if (tree_forwarder_block_p (bb, false)
       && remove_forwarder_block (bb))
     return true;