[turbofan] Add comments to CodeAssembler

src/compiler/opcodes.h

 // Copyright 2013 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_OPCODES_H_
 #define V8_COMPILER_OPCODES_H_
 
 #include <iosfwd>
 
 // Opcodes for control operators.
@@ skipping 236 matching lines @@
   V(Float32Equal)                     \
   V(Float32LessThan)                  \
   V(Float32LessThanOrEqual)           \
   V(Float64Equal)                     \
   V(Float64LessThan)                  \
   V(Float64LessThanOrEqual)
 
 #define MACHINE_OP_LIST(V)      \
   MACHINE_COMPARE_BINOP_LIST(V) \
   V(DebugBreak)                 \
+  V(Comment)                    \
   V(Load)                       \
   V(Store)                      \
   V(StackSlot)                  \
   V(Word32And)                  \
   V(Word32Or)                   \
   V(Word32Xor)                  \
   V(Word32Shl)                  \
   V(Word32Shr)                  \
   V(Word32Sar)                  \
   V(Word32Ror)                  \
@@ skipping 373 matching lines @@
   }
 };
 
 std::ostream& operator<<(std::ostream&, IrOpcode::Value);
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_OPCODES_H_