diff --git a/lib/CodeGen/SplitKit.cpp b/lib/CodeGen/SplitKit.cpp
index 6195ab0..f85d5d3 100644
--- a/lib/CodeGen/SplitKit.cpp
+++ b/lib/CodeGen/SplitKit.cpp
@@ -557,7 +557,7 @@
 }
 
 /// Create a new virtual register and live interval.
-void SplitEditor::openIntv() {
+unsigned SplitEditor::openIntv() {
   assert(!OpenIdx && "Previous LI not closed before openIntv");
 
   // Create the complement as index 0.
@@ -567,6 +567,13 @@
   // Create the open interval.
   OpenIdx = Edit->size();
   Edit->create(LIS, VRM);
+  return OpenIdx;
+}
+
+void SplitEditor::selectIntv(unsigned Idx) {
+  assert(Idx != 0 && "Cannot select the complement interval");
+  assert(Idx < Edit->size() && "Can only select previously opened interval");
+  OpenIdx = Idx;
 }
 
 SlotIndex SplitEditor::enterIntvBefore(SlotIndex Idx) {
diff --git a/lib/CodeGen/SplitKit.h b/lib/CodeGen/SplitKit.h
index f1ff501..fab56f7 100644
--- a/lib/CodeGen/SplitKit.h
+++ b/lib/CodeGen/SplitKit.h
@@ -283,7 +283,15 @@
   void reset(LiveRangeEdit&);
 
   /// Create a new virtual register and live interval.
-  void openIntv();
+  /// Return the interval index, starting from 1. Interval index 0 is the
+  /// implicit complement interval.
+  unsigned openIntv();
+
+  /// currentIntv - Return the current interval index.
+  unsigned currentIntv() const { return OpenIdx; }
+
+  /// selectIntv - Select a previously opened interval index.
+  void selectIntv(unsigned Idx);
 
   /// enterIntvBefore - Enter the open interval before the instruction at Idx.
   /// If the parent interval is not live before Idx, a COPY is not inserted.