[interpreter] Use VisitForTest for loop conditions

src/compiler/bytecode-loop-analysis.h

 // Copyright 2016 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_BYTECODE_LOOP_ANALYSIS_H_
 #define V8_COMPILER_BYTECODE_LOOP_ANALYSIS_H_
 
 #include "src/handles.h"
 #include "src/zone-containers.h"
 
@@ skipping 29 matching lines @@
   void AddBranch(int origin_offset, int target_offset);
 
   Zone* zone() const { return zone_; }
   Handle<BytecodeArray> bytecode_array() const { return bytecode_array_; }
 
   Handle<BytecodeArray> bytecode_array_;
   const BytecodeBranchAnalysis* branch_analysis_;
   Zone* zone_;
 
   int current_loop_offset_;
+  bool found_current_backedge_;
 
   // Map from the offset of a backedge jump to the offset of the corresponding
-  // loop header. Since we assume exactly one backedge per loop, the map will
-  // have as many entries as there are loops.
+  // loop header. There might be multiple backedges for do-while loops.
   ZoneMap<int, int> backedge_to_header_;
   // Map from the offset of a loop header to the offset of its parent's loop
   // header. This map will have as many entries as there are loops in the
   // function.
   ZoneMap<int, int> loop_header_to_parent_;
 
   DISALLOW_COPY_AND_ASSIGN(BytecodeLoopAnalysis);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_BYTECODE_LOOP_ANALYSIS_H_