Correctify instanceof and make it optimizable.

src/full-codegen/x64/full-codegen-x64.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_X64
 
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
 #include "src/codegen.h"
 #include "src/compiler.h"
@@ skipping 5023 matching lines @@
   switch (op) {
     case Token::IN:
       VisitForStackValue(expr->right());
       __ InvokeBuiltin(Builtins::IN, CALL_FUNCTION);
       PrepareForBailoutBeforeSplit(expr, false, NULL, NULL);
       __ CompareRoot(rax, Heap::kTrueValueRootIndex);
       Split(equal, if_true, if_false, fall_through);
       break;
 
     case Token::INSTANCEOF: {
-      VisitForStackValue(expr->right());
-      InstanceofStub stub(isolate(), InstanceofStub::kNoFlags);
+      VisitForAccumulatorValue(expr->right());
+      __ Pop(rdx);
+      InstanceOfStub stub(isolate());
       __ CallStub(&stub);
-      PrepareForBailoutBeforeSplit(expr, true, if_true, if_false);
-      __ testp(rax, rax);
-       // The stub returns 0 for true.
-      Split(zero, if_true, if_false, fall_through);
+      PrepareForBailoutBeforeSplit(expr, false, NULL, NULL);
+      __ CompareRoot(rax, Heap::kTrueValueRootIndex);
+      Split(equal, if_true, if_false, fall_through);
       break;
     }
 
     default: {
       VisitForAccumulatorValue(expr->right());
       Condition cc = CompareIC::ComputeCondition(op);
       __ Pop(rdx);
 
       bool inline_smi_code = ShouldInlineSmiCase(op);
       JumpPatchSite patch_site(masm_);
@@ skipping 240 matching lines @@
             Assembler::target_address_at(call_target_address,
                                          unoptimized_code));
   return OSR_AFTER_STACK_CHECK;
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64