[turbofan] compress live_in bitvectors

src/compiler/register-allocator.h

Index: src/compiler/register-allocator.h
diff --git a/src/compiler/register-allocator.h b/src/compiler/register-allocator.h
index 881ce37f7d590e2fc2983e4f5388397357797d73..134379b53a16dffd001dbe6a66099cd6622b401b 100644
--- a/src/compiler/register-allocator.h
+++ b/src/compiler/register-allocator.h
@@ -382,12 +382,11 @@ class RegisterAllocator BASE_EMBEDDED {
   inline bool SafePointsAreInOrder() const;
 
   // Liveness analysis support.
-  void InitializeLivenessAnalysis();
-  BitVector* ComputeLiveOut(BasicBlock* block);
-  void AddInitialIntervals(BasicBlock* block, BitVector* live_out);
+  void ComputeLiveOut(BasicBlock* block);
+  void AddInitialIntervals(BasicBlock* block);
   bool IsOutputRegisterOf(Instruction* instr, int index);
   bool IsOutputDoubleRegisterOf(Instruction* instr, int index);
-  void ProcessInstructions(BasicBlock* block, BitVector* live);
+  void ProcessInstructions(BasicBlock* block);
   void MeetRegisterConstraints(BasicBlock* block);
   void MeetConstraintsBetween(Instruction* first, Instruction* second,
                               int gap_index);
@@ -498,7 +497,8 @@ class RegisterAllocator BASE_EMBEDDED {
 
   // During liveness analysis keep a mapping from block id to live_in sets
   // for blocks already analyzed.
-  ZoneList<BitVector*> live_in_sets_;
+  class LiveInSets;
+  LiveInSets* live_in_sets_;
 
   // Liveness analysis results.
   ZoneList<LiveRange*> live_ranges_;