Reland of [turbofan] Insert dummy values when changing from None type.

src/compiler/instruction-codes.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_CODES_H_
 #define V8_COMPILER_INSTRUCTION_CODES_H_
 
 #include <iosfwd>
 
 #if V8_TARGET_ARCH_ARM
@@ skipping 39 matching lines @@
   V(ArchTailCallJSFunction)               \
   V(ArchTailCallAddress)                  \
   V(ArchPrepareCallCFunction)             \
   V(ArchCallCFunction)                    \
   V(ArchPrepareTailCall)                  \
   V(ArchJmp)                              \
   V(ArchLookupSwitch)                     \
   V(ArchTableSwitch)                      \
   V(ArchNop)                              \
   V(ArchDebugBreak)                       \
-  V(ArchImpossible)                       \
   V(ArchComment)                          \
   V(ArchThrowTerminator)                  \
   V(ArchDeoptimize)                       \
   V(ArchRet)                              \
   V(ArchStackPointer)                     \
   V(ArchFramePointer)                     \
   V(ArchParentFramePointer)               \
   V(ArchTruncateDoubleToI)                \
   V(ArchStoreWithWriteBarrier)            \
   V(CheckedLoadInt8)                      \
@@ skipping 135 matching lines @@
 typedef BitField<AddressingMode, 8, 5> AddressingModeField;
 typedef BitField<FlagsMode, 13, 2> FlagsModeField;
 typedef BitField<FlagsCondition, 15, 5> FlagsConditionField;
 typedef BitField<int, 20, 12> MiscField;
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_INSTRUCTION_CODES_H_