[compiler] Drop the CompareNilIC.

src/types.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_TYPES_H_
 #define V8_TYPES_H_
 
 #include "src/conversions.h"
 #include "src/handles.h"
 #include "src/objects.h"
@@ skipping 24 matching lines @@
 //   Number = Signed32 \/ Unsigned32 \/ Double
 //   Smi <= Signed32
 //   Name = String \/ Symbol
 //   UniqueName = InternalizedString \/ Symbol
 //   InternalizedString < String
 //
 //   Receiver = Object \/ Proxy
 //   Array < Object
 //   Function < Object
 //   RegExp < Object
-//   Undetectable < Object
-//   Detectable = Receiver \/ Number \/ Name - Undetectable
+//   OtherUndetectable < Object
+//   DetectableReceiver = Receiver - OtherUndetectable
 //
 //   Class(map) < T   iff instance_type(map) < T
 //   Constant(x) < T  iff instance_type(map(x)) < T
 //   Array(T) < Array
 //   Function(R, S, T0, T1, ...) < Function
 //   Context(T) < Internal
 //
 // Both structural Array and Function types are invariant in all parameters;
 // relaxing this would make Union and Intersect operations more involved.
 // There is no subtyping relation between Array, Function, or Context types
@@ skipping 131 matching lines @@
   V(Null,                1u << 6  | REPRESENTATION(kTaggedPointer)) \
   V(Undefined,           1u << 7  | REPRESENTATION(kTaggedPointer)) \
   V(Boolean,             1u << 8  | REPRESENTATION(kTaggedPointer)) \
   V(Unsigned30,          1u << 9  | REPRESENTATION(kTagged | kUntaggedNumber)) \
   V(MinusZero,           1u << 10 | REPRESENTATION(kTagged | kUntaggedNumber)) \
   V(NaN,                 1u << 11 | REPRESENTATION(kTagged | kUntaggedNumber)) \
   V(Symbol,              1u << 12 | REPRESENTATION(kTaggedPointer)) \
   V(InternalizedString,  1u << 13 | REPRESENTATION(kTaggedPointer)) \
   V(OtherString,         1u << 14 | REPRESENTATION(kTaggedPointer)) \
   V(Simd,                1u << 15 | REPRESENTATION(kTaggedPointer)) \
-  V(Undetectable,        1u << 16 | REPRESENTATION(kTaggedPointer)) \
   V(OtherObject,         1u << 17 | REPRESENTATION(kTaggedPointer)) \
+  V(OtherUndetectable,   1u << 16 | REPRESENTATION(kTaggedPointer)) \
   V(Proxy,               1u << 18 | REPRESENTATION(kTaggedPointer)) \
   V(Function,            1u << 19 | REPRESENTATION(kTaggedPointer)) \
   V(Internal,            1u << 20 | REPRESENTATION(kTagged | kUntagged)) \
   \
   V(Signed31,                 kUnsigned30 | kNegative31) \
   V(Signed32,                 kSigned31 | kOtherUnsigned31 | kOtherSigned32) \
   V(Negative32,               kNegative31 | kOtherSigned32) \
   V(Unsigned31,               kUnsigned30 | kOtherUnsigned31) \
   V(Unsigned32,               kUnsigned30 | kOtherUnsigned31 | \
                               kOtherUnsigned32) \
   V(Integral32,               kSigned32 | kUnsigned32) \
   V(PlainNumber,              kIntegral32 | kOtherNumber) \
   V(OrderedNumber,            kPlainNumber | kMinusZero) \
   V(MinusZeroOrNaN,           kMinusZero | kNaN) \
   V(Number,                   kOrderedNumber | kNaN) \
   V(String,                   kInternalizedString | kOtherString) \
   V(UniqueName,               kSymbol | kInternalizedString) \
   V(Name,                     kSymbol | kString) \
   V(BooleanOrNumber,          kBoolean | kNumber) \
   V(BooleanOrNullOrUndefined, kBoolean | kNull | kUndefined) \
   V(NullOrUndefined,          kNull | kUndefined) \
+  V(Undetectable,             kNullOrUndefined | kOtherUndetectable) \
   V(NumberOrString,           kNumber | kString) \
   V(NumberOrUndefined,        kNumber | kUndefined) \
   V(PlainPrimitive,           kNumberOrString | kBoolean | kNullOrUndefined) \
   V(Primitive,                kSymbol | kSimd | kPlainPrimitive) \
   V(DetectableReceiver,       kFunction | kOtherObject | kProxy) \
-  V(Detectable,               kDetectableReceiver | kNumber | kName) \
-  V(Object,                   kFunction | kOtherObject | kUndetectable) \
+  V(Object,                   kFunction | kOtherObject | kOtherUndetectable) \
   V(Receiver,                 kObject | kProxy) \
   V(StringOrReceiver,         kString | kReceiver) \
   V(Unique,                   kBoolean | kUniqueName | kNull | kUndefined | \
                               kReceiver) \
   V(NonNumber,                kUnique | kString | kInternal) \
   V(Any,                      0xfffffffeu)
 
 // clang-format on
 
 /*
@@ skipping 724 matching lines @@
 
   bool Narrows(Bounds that) {
     return that.lower->Is(this->lower) && this->upper->Is(that.upper);
   }
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TYPES_H_