X87: [compiler] Drop the CompareNilIC.

src/full-codegen/x87/full-codegen-x87.cc

 // 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.
 
 #if V8_TARGET_ARCH_X87
 
 #include "src/ast/scopes.h"
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
 #include "src/codegen.h"
@@ skipping 3869 matching lines @@
   VisitForAccumulatorValue(sub_expr);
   PrepareForBailoutBeforeSplit(expr, true, if_true, if_false);
 
   Handle<Object> nil_value = nil == kNullValue
       ? isolate()->factory()->null_value()
       : isolate()->factory()->undefined_value();
   if (expr->op() == Token::EQ_STRICT) {
     __ cmp(eax, nil_value);
     Split(equal, if_true, if_false, fall_through);
   } else {
-    Handle<Code> ic = CompareNilICStub::GetUninitialized(isolate(), nil);
-    CallIC(ic, expr->CompareOperationFeedbackId());
-    __ cmp(eax, isolate()->factory()->true_value());
-    Split(equal, if_true, if_false, fall_through);
+    __ JumpIfSmi(eax, if_false);
+    __ mov(eax, FieldOperand(eax, HeapObject::kMapOffset));
+    __ test_b(FieldOperand(eax, Map::kBitFieldOffset),
+              1 << Map::kIsUndetectable);
+    Split(not_zero, if_true, if_false, fall_through);
   }
   context()->Plug(if_true, if_false);
 }
 
 
 void FullCodeGenerator::VisitThisFunction(ThisFunction* expr) {
   __ mov(eax, Operand(ebp, JavaScriptFrameConstants::kFunctionOffset));
   context()->Plug(eax);
 }
 
@@ skipping 183 matching lines @@
             Assembler::target_address_at(call_target_address,
                                          unoptimized_code));
   return OSR_AFTER_STACK_CHECK;
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X87