[turbofan] Splinter when range ends at hot block start

src/compiler/register-allocator.h

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_REGISTER_ALLOCATOR_H_
 #define V8_REGISTER_ALLOCATOR_H_
 
 #include "src/compiler/instruction.h"
 #include "src/ostreams.h"
 #include "src/register-configuration.h"
@@ skipping 178 matching lines @@
   LifetimePosition Intersect(const UseInterval* other) const {
     if (other->start() < start_) return other->Intersect(this);
     if (other->start() < end_) return other->start();
     return LifetimePosition::Invalid();
   }
 
   bool Contains(LifetimePosition point) const {
     return start_ <= point && point < end_;
   }
 
-  int FirstInstructionIndex() const {
+  // Returns the index of the first gap covered by this interval.
+  int FirstGapIndex() const {
     int ret = start_.ToInstructionIndex();
-    if (start_.IsInstructionPosition() && start_.IsEnd()) {
+    if (start_.IsInstructionPosition()) {
       ++ret;
     }
     return ret;
   }
 
-  int LastInstructionIndex() const {
+  // Returns the index of the last gap covered by this interval.
+  int LastGapIndex() const {
     int ret = end_.ToInstructionIndex();
-    if (end_.IsGapPosition() || end_.IsStart()) {
+    if (end_.IsGapPosition() && end_.IsStart()) {
       --ret;
     }
     return ret;
   }
 
  private:
   LifetimePosition start_;
   LifetimePosition end_;
   UseInterval* next_;
 
@@ skipping 923 matching lines @@
   // branches.
   void ResolveControlFlow(Zone* local_zone);
 
  private:
   RegisterAllocationData* data() const { return data_; }
   InstructionSequence* code() const { return data()->code(); }
   Zone* code_zone() const { return code()->zone(); }
 
   bool CanEagerlyResolveControlFlow(const InstructionBlock* block) const;
 
-  void ResolveControlFlow(const InstructionBlock* block,
-                          const InstructionOperand& cur_op,
-                          const InstructionBlock* pred,
-                          const InstructionOperand& pred_op);
+  int ResolveControlFlow(const InstructionBlock* block,
+                         const InstructionOperand& cur_op,
+                         const InstructionBlock* pred,
+                         const InstructionOperand& pred_op);
 
   RegisterAllocationData* const data_;
 
   DISALLOW_COPY_AND_ASSIGN(LiveRangeConnector);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_REGISTER_ALLOCATOR_H_