re PR tree-optimization/30590 (tree-nrv optimization clobbers return variable)

2007-03-13  Seongbae Park <seongbae.park@gmail.com>

	PR tree-optimization/30590
	* tree-nrv.c (tree_nrv): Check for the partial update of the
	return value.

From-SVN: r122909

gcc/ChangeLog

+2007-03-13  Seongbae Park <seongbae.park@gmail.com>
+
+	PR tree-optimization/30590
+	* tree-nrv.c (tree_nrv): Check for the partial update of the
+	return value.
+
 2007-03-13  Alexandre Oliva  <aoliva@redhat.com>
 
 	* flags.h (flag_random_seed): Remove declaration, in favor of...

gcc/tree-nrv.c

@@ -163,6 +163,14 @@ tree_nrv (void)
 						     result_type))
 		return 0;
 	    }
+	  else if (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT)
+	    {
+	      tree addr = get_base_address (GIMPLE_STMT_OPERAND (stmt, 0));
+	       /* If there's any MODIFY of component of RESULT, 
+		  then bail out.  */
+	      if (addr && addr == result)
+		return 0;
+	    }
 	}
     }