For the values defined in the loop and spilled outside sink spill store out of the loop down to loo…

src/lithium-allocator.h

Index: src/lithium-allocator.h
diff --git a/src/lithium-allocator.h b/src/lithium-allocator.h
index 5b05263575dcc45d2d1f9e53ee8066054660d49f..6259a195b46441c06677066dacc09482658ea7e3 100644
--- a/src/lithium-allocator.h
+++ b/src/lithium-allocator.h
@@ -290,7 +290,10 @@ class LiveRange: public ZoneObject {
   bool IsEmpty() const { return first_interval() == NULL; }
   LOperand* CreateAssignedOperand(Zone* zone);
   int assigned_register() const { return assigned_register_; }
+
   int spill_start_index() const { return spill_start_index_; }
+  void set_spill_start_index(int start) { spill_start_index_ = start; }
+
   void set_assigned_register(int reg,
                              RegisterKind register_kind,
                              Zone* zone);
@@ -347,10 +350,6 @@ class LiveRange: public ZoneObject {
   LOperand* GetSpillOperand() const { return spill_operand_; }
   void SetSpillOperand(LOperand* operand);
 
-  void SetSpillStartIndex(int start) {
-    spill_start_index_ = Min(start, spill_start_index_);
-  }
-
   bool ShouldBeAllocatedBefore(const LiveRange* other) const;
   bool CanCover(LifetimePosition position) const;
   bool Covers(LifetimePosition position);
@@ -376,6 +375,24 @@ class LiveRange: public ZoneObject {
   void Verify() const;
 #endif
 
+  static const intptr_t kDisabledSpillStoreSinkingMarker = -1;
+
+  LOperand* spill_source() { return spill_source_; }
+  void set_spill_source(LOperand* spill_source) {
+    spill_source_ = spill_source;
+  }
+
+  bool HasPendingSpillStore() {
+    return (spill_source() !=
+            reinterpret_cast<LOperand*>(kDisabledSpillStoreSinkingMarker)) &&
+        (spill_source() != NULL);
+  }
+
+  void DisableSpillStoreSinking() {
+    set_spill_source(
+        reinterpret_cast<LOperand*>(kDisabledSpillStoreSinkingMarker));
+  }
+
  private:
   void ConvertOperands(Zone* zone);
   UseInterval* FirstSearchIntervalForPosition(LifetimePosition position) const;
@@ -396,6 +413,7 @@ class LiveRange: public ZoneObject {
   UsePosition* last_processed_use_;
   LOperand* spill_operand_;
   int spill_start_index_;
+  LOperand* spill_source_;
 };
 
 
@@ -564,6 +582,17 @@ class LAllocator BASE_EMBEDDED {
   void SplitAndSpillIntersecting(LiveRange* range);
 
   void Spill(LiveRange* range);
+
+  // Emit spill store for the given range that moves value from the register
+  // where it was produced (spill source) to the allocated spill slot.
+  void EmitSpillStore(LiveRange* range);
+  void EmitSpillStore(int pos, LOperand* source, LOperand* spill);
+
+  // Try sink spill store for the given range down to the beginning of the
+  // given block. This is done only if the block dominates all spilled split
+  // siblings.
+  bool TrySinkSpillStoreTo(LiveRange* range, HBasicBlock* block);
+
   bool IsBlockBoundary(LifetimePosition pos);
 
   // Helper methods for resolving control flow.
@@ -571,6 +600,10 @@ class LAllocator BASE_EMBEDDED {
                           HBasicBlock* block,
                           HBasicBlock* pred);
 
+  // Emit all pending spill stores for ranges that have spilled siblings sinking
+  // stores down to loop exits whenever possible.
+  void SinkSpillStores();
+
   // Return parallel move that should be used to connect ranges split at the
   // given position.
   LParallelMove* GetConnectingParallelMove(LifetimePosition pos);
@@ -617,6 +650,10 @@ class LAllocator BASE_EMBEDDED {
   ZoneList<LiveRange*> inactive_live_ranges_;
   ZoneList<LiveRange*> reusable_slots_;
 
+  // List of live ranges that were spilled but did not have
+  // spill store emitted eagerly.
+  ZoneList<LiveRange*> pending_spilled_;
+
   // Next virtual register number to be assigned to temporaries.
   int next_virtual_register_;
   int first_artificial_register_;