Treat all kArchNop instuctions as NOPs in jump threading.

src/compiler/instruction.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_COMPILER_INSTRUCTION_H_
 #define V8_COMPILER_INSTRUCTION_H_
 
 #include <deque>
 #include <iosfwd>
 #include <map>
@@ skipping 838 matching lines @@
     DCHECK(!reference_map_);
     reference_map_ = map;
   }
 
   void OverwriteWithNop() {
     opcode_ = ArchOpcodeField::encode(kArchNop);
     bit_field_ = 0;
     reference_map_ = nullptr;
   }
 
-  bool IsNop() const {
-    return arch_opcode() == kArchNop && InputCount() == 0 &&
-           OutputCount() == 0 && TempCount() == 0;
-  }
+  bool IsNop() const { return arch_opcode() == kArchNop; }
 
   bool IsDeoptimizeCall() const {
     return arch_opcode() == ArchOpcode::kArchDeoptimize ||
            FlagsModeField::decode(opcode()) == kFlags_deoptimize;
   }
 
   bool IsJump() const { return arch_opcode() == ArchOpcode::kArchJmp; }
   bool IsRet() const { return arch_opcode() == ArchOpcode::kArchRet; }
   bool IsTailCall() const {
     return arch_opcode() == ArchOpcode::kArchTailCallCodeObject ||
@@ skipping 615 matching lines @@
 
 
 std::ostream& operator<<(std::ostream& os,
                          const PrintableInstructionSequence& code);
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_INSTRUCTION_H_