--- a/lib/CodeGen/LiveRangeCalc.h	Tue Jan 26 22:56:36 2016 +0900
+++ b/lib/CodeGen/LiveRangeCalc.h	Fri Nov 25 19:14:25 2016 +0900
@@ -22,6 +22,7 @@
 #ifndef LLVM_LIB_CODEGEN_LIVERANGECALC_H
 #define LLVM_LIB_CODEGEN_LIVERANGECALC_H
 
+#include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/BitVector.h"
 #include "llvm/ADT/IndexedMap.h"
 #include "llvm/CodeGen/LiveInterval.h"
@@ -53,6 +54,19 @@
   /// when switching live ranges.
   BitVector Seen;
 
+  /// Map LiveRange to sets of blocks (represented by bit vectors) that
+  /// in the live range are defined on entry and undefined on entry.
+  /// A block is defined on entry if there is a path from at least one of
+  /// the defs in the live range to the entry of the block, and conversely,
+  /// a block is undefined on entry, if there is no such path (i.e. no
+  /// definition reaches the entry of the block). A single LiveRangeCalc
+  /// object is used to track live-out information for multiple registers
+  /// in live range splitting (which is ok, since the live ranges of these
+  /// registers do not overlap), but the defined/undefined information must
+  /// be kept separate for each individual range.
+  /// By convention, EntryInfoMap[&LR] = { Defined, Undefined }.
+  std::map<LiveRange*,std::pair<BitVector,BitVector>> EntryInfoMap;
+
   /// Map each basic block where a live range is live out to the live-out value
   /// and its defining block.
   ///
@@ -101,18 +115,31 @@
   /// used to add entries directly.
   SmallVector<LiveInBlock, 16> LiveIn;
 
-  /// Assuming that @p LR is live-in to @p UseMBB, find the set of defs that can
-  /// reach it.
+  /// Check if the entry to block @p MBB can be reached by any of the defs
+  /// in @p LR. Return true if none of the defs reach the entry to @p MBB.
+  bool isDefOnEntry(LiveRange &LR, ArrayRef<SlotIndex> Undefs,
+                    MachineBasicBlock &MBB, BitVector &DefOnEntry,
+                    BitVector &UndefOnEntry);
+
+  /// Find the set of defs that can reach @p Kill. @p Kill must belong to
+  /// @p UseMBB.
   ///
-  /// If only one def can reach @p UseMBB, all paths from the def to @p UseMBB
-  /// are added to @p LR, and the function returns true.
+  /// If exactly one def can reach @p UseMBB, and the def dominates @p Kill,
+  /// all paths from the def to @p UseMBB are added to @p LR, and the function
+  /// returns true.
   ///
   /// If multiple values can reach @p UseMBB, the blocks that need @p LR to be
   /// live in are added to the LiveIn array, and the function returns false.
   ///
+  /// The array @p Undef provides the locations where the range @p LR becomes
+  /// undefined by <def,read-undef> operands on other subranges. If @p Undef
+  /// is non-empty and @p Kill is jointly dominated only by the entries of
+  /// @p Undef, the function returns false.
+  ///
   /// PhysReg, when set, is used to verify live-in lists on basic blocks.
   bool findReachingDefs(LiveRange &LR, MachineBasicBlock &UseMBB,
-                        SlotIndex Kill, unsigned PhysReg);
+                        SlotIndex Kill, unsigned PhysReg,
+                        ArrayRef<SlotIndex> Undefs);
 
   /// updateSSA - Compute the values that will be live in to all requested
   /// blocks in LiveIn.  Create PHI-def values as required to preserve SSA form.
@@ -127,9 +154,15 @@
 
   /// Extend the live range of @p LR to reach all uses of Reg.
   ///
-  /// All uses must be jointly dominated by existing liveness.  PHI-defs are
-  /// inserted as needed to preserve SSA form.
-  void extendToUses(LiveRange &LR, unsigned Reg, LaneBitmask LaneMask);
+  /// If @p LR is a main range, or if @p LI is null, then all uses must be
+  /// jointly dominated by the definitions from @p LR. If @p LR is a subrange
+  /// of the live interval @p LI, corresponding to lane mask @p LaneMask,
+  /// all uses must be jointly dominated by the definitions from @p LR
+  /// together with definitions of other lanes where @p LR becomes undefined
+  /// (via <def,read-undef> operands).
+  /// If @p LR is a main range, the @p LaneMask should be set to ~0.
+  void extendToUses(LiveRange &LR, unsigned Reg, LaneBitmask LaneMask,
+                    LiveInterval *LI = nullptr);
 
   /// Reset Map and Seen fields.
   void resetLiveOutMap();
@@ -169,7 +202,8 @@
   /// inserted as required to preserve SSA form.
   ///
   /// PhysReg, when set, is used to verify live-in lists on basic blocks.
-  void extend(LiveRange &LR, SlotIndex Use, unsigned PhysReg = 0);
+  void extend(LiveRange &LR, SlotIndex Use, unsigned PhysReg,
+              ArrayRef<SlotIndex> Undefs);
 
   /// createDeadDefs - Create a dead def in LI for every def operand of Reg.
   /// Each instruction defining Reg gets a new VNInfo with a corresponding
@@ -189,6 +223,11 @@
   /// enabled.
   void calculate(LiveInterval &LI, bool TrackSubRegs);
 
+  /// For live interval \p LI with correct SubRanges construct matching
+  /// information for the main live range. Expects the main live range to not
+  /// have any segments or value numbers.
+  void constructMainRangeFromSubranges(LiveInterval &LI);
+
   //===--------------------------------------------------------------------===//
   // Low-level interface.
   //===--------------------------------------------------------------------===//