[turbofan] Rework handling of loop exits in loop peeling.

src/compiler/loop-peeling.h

 // Copyright 2015 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_COMPILER_LOOP_PEELING_H_
 #define V8_COMPILER_LOOP_PEELING_H_
 
 #include "src/compiler/loop-analysis.h"
 
 namespace v8 {
@@ skipping 11 matching lines @@
 
  protected:
   PeeledIteration() {}
 };
 
 class CommonOperatorBuilder;
 
 // Implements loop peeling.
 class LoopPeeler {
  public:
+  static bool CanPeel(LoopTree* loop_tree, LoopTree::Loop* loop);
   static PeeledIteration* Peel(Graph* graph, CommonOperatorBuilder* common,
                                LoopTree* loop_tree, LoopTree::Loop* loop,
                                Zone* tmp_zone);
 };
 
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_LOOP_PEELING_H_