new file, obviously just a stub

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@22868 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/SelectionDAG/ScheduleDAG.cpp

@@ -0,0 +1,23 @@
+//===-- ScheduleDAG.cpp - Implement a trivial DAG scheduler ---------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by Chris Lattner and is distributed under the
+// University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This implements a simple code linearizer for DAGs.  This is not a very good
+// way to emit code, but gets working code quickly.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "sched"
+#include "llvm/CodeGen/SelectionDAGISel.h"
+using namespace llvm;
+
+/// Pick a safe ordering and emit instructions for each target node in the
+/// graph.
+void SelectionDAGISel::ScheduleAndEmitDAG(SelectionDAG &SD) {
+  
+}