Revert of [compiler] Drop the CompareNilIC.

src/objects-inl.h

 // Copyright 2012 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.
 //
 // Review notes:
 //
 // - The use of macros in these inline functions may seem superfluous
 // but it is absolutely needed to make sure gcc generates optimal
 // code. gcc is not happy when attempting to inline too deep.
 //
@@ skipping 4668 matching lines @@
 
 Code::Kind Code::kind() {
   return ExtractKindFromFlags(flags());
 }
 
 
 bool Code::IsCodeStubOrIC() {
   return kind() == STUB || kind() == HANDLER || kind() == LOAD_IC ||
          kind() == KEYED_LOAD_IC || kind() == CALL_IC || kind() == STORE_IC ||
          kind() == KEYED_STORE_IC || kind() == BINARY_OP_IC ||
-         kind() == COMPARE_IC || kind() == TO_BOOLEAN_IC;
+         kind() == COMPARE_IC || kind() == COMPARE_NIL_IC ||
+         kind() == TO_BOOLEAN_IC;
 }
 
 
 bool Code::IsJavaScriptCode() {
   return kind() == FUNCTION || kind() == OPTIMIZED_FUNCTION ||
          is_interpreter_entry_trampoline();
 }
 
 
 InlineCacheState Code::ic_state() {
@@ skipping 269 matching lines @@
 
 bool Code::is_debug_stub() { return ic_state() == DEBUG_STUB; }
 bool Code::is_handler() { return kind() == HANDLER; }
 bool Code::is_load_stub() { return kind() == LOAD_IC; }
 bool Code::is_keyed_load_stub() { return kind() == KEYED_LOAD_IC; }
 bool Code::is_store_stub() { return kind() == STORE_IC; }
 bool Code::is_keyed_store_stub() { return kind() == KEYED_STORE_IC; }
 bool Code::is_call_stub() { return kind() == CALL_IC; }
 bool Code::is_binary_op_stub() { return kind() == BINARY_OP_IC; }
 bool Code::is_compare_ic_stub() { return kind() == COMPARE_IC; }
+bool Code::is_compare_nil_ic_stub() { return kind() == COMPARE_NIL_IC; }
 bool Code::is_to_boolean_ic_stub() { return kind() == TO_BOOLEAN_IC; }
 bool Code::is_optimized_code() { return kind() == OPTIMIZED_FUNCTION; }
 bool Code::is_wasm_code() { return kind() == WASM_FUNCTION; }
 
 bool Code::embeds_maps_weakly() {
   Kind k = kind();
   return (k == LOAD_IC || k == STORE_IC || k == KEYED_LOAD_IC ||
-          k == KEYED_STORE_IC) &&
+          k == KEYED_STORE_IC || k == COMPARE_NIL_IC) &&
          ic_state() == MONOMORPHIC;
 }
 
 
 Address Code::constant_pool() {
   Address constant_pool = NULL;
   if (FLAG_enable_embedded_constant_pool) {
     int offset = constant_pool_offset();
     if (offset < instruction_size()) {
       constant_pool = FIELD_ADDR(this, kHeaderSize + offset);
@@ skipping 2686 matching lines @@
 #undef WRITE_INT64_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 #undef NOBARRIER_READ_BYTE_FIELD
 #undef NOBARRIER_WRITE_BYTE_FIELD
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_OBJECTS_INL_H_