[turbofan] optimize hot loop in ResolveControlFlow

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 40fafb1dcf7c5c92a163544a9cf73d4a217a06a9..7cd3f30d434d5e8babcb050bc4aad4eea962a73f 100644
--- a/src/compiler/register-allocator.h
+++ b/src/compiler/register-allocator.h
@@ -186,12 +186,15 @@ class LiveRange FINAL : public ZoneObject {
   UsePosition* first_pos() const { return first_pos_; }
   LiveRange* parent() const { return parent_; }
   LiveRange* TopLevel() { return (parent_ == NULL) ? this : parent_; }
+  const LiveRange* TopLevel() const {
+    return (parent_ == NULL) ? this : parent_;
+  }
   LiveRange* next() const { return next_; }
   bool IsChild() const { return parent() != NULL; }
   int id() const { return id_; }
   bool IsFixed() const { return id_ < 0; }
   bool IsEmpty() const { return first_interval() == NULL; }
-  InstructionOperand* CreateAssignedOperand(Zone* zone);
+  InstructionOperand* CreateAssignedOperand(Zone* zone) const;
   int assigned_register() const { return assigned_register_; }
   int spill_start_index() const { return spill_start_index_; }
   void set_assigned_register(int reg, Zone* zone);
@@ -347,6 +350,8 @@ class RegisterAllocator BASE_EMBEDDED {
     return fixed_double_live_ranges_;
   }
   InstructionSequence* code() const { return code_; }
+  // This zone is for datastructures only needed during register allocation.
+  Zone* zone() const { return zone_; }

[Jarin, 2014/11/04 10:42:09]

Since you already touching this, could you possibly rename to local_zone()?

[dcarney, 2014/11/05 09:02:02]

Done.

 
  private:
   int GetVirtualRegister() {
@@ -366,9 +371,6 @@ class RegisterAllocator BASE_EMBEDDED {
   // Returns the register kind required by the given virtual register.
   RegisterKind RequiredRegisterKind(int virtual_register) const;
 
-  // This zone is for datastructures only needed during register allocation.
-  Zone* zone() const { return zone_; }
-
   // This zone is for InstructionOperands and moves that live beyond register
   // allocation.
   Zone* code_zone() const { return code()->zone(); }
@@ -475,8 +477,10 @@ class RegisterAllocator BASE_EMBEDDED {
   bool IsBlockBoundary(LifetimePosition pos);
 
   // Helper methods for resolving control flow.
-  void ResolveControlFlow(LiveRange* range, const InstructionBlock* block,
-                          const InstructionBlock* pred);
+  void ResolveControlFlow(const InstructionBlock* block,
+                          const LiveRange* cur_cover,
+                          const InstructionBlock* pred,
+                          const LiveRange* pred_cover);
 
   void SetLiveRangeAssignedRegister(LiveRange* range, int reg);