Revert of Version 5.0.71.10 (cherry-pick)

src/x64/code-stubs-x64.cc

 // Copyright 2013 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/bootstrapper.h"
 #include "src/code-stubs.h"
 #include "src/codegen.h"
 #include "src/ic/handler-compiler.h"
@@ skipping 1302 matching lines @@
 
     __ bind(&undetectable);
     __ testb(FieldOperand(rcx, Map::kBitFieldOffset),
              Immediate(1 << Map::kIsUndetectable));
     __ j(zero, &return_unequal);
     __ Set(rax, EQUAL);
     __ ret(0);
   }
   __ bind(&runtime_call);
 
+  // Push arguments below the return address to prepare jump to builtin.
+  __ PopReturnAddressTo(rcx);
+  __ Push(rdx);
+  __ Push(rax);
+
+  // Figure out which native to call and setup the arguments.
   if (cc == equal) {
-    {
-      FrameScope scope(masm, StackFrame::INTERNAL);
-      __ Push(rdx);
-      __ Push(rax);
-      __ CallRuntime(strict() ? Runtime::kStrictEqual : Runtime::kEqual);
-    }
-    // Turn true into 0 and false into some non-zero value.
-    STATIC_ASSERT(EQUAL == 0);
-    __ LoadRoot(rdx, Heap::kTrueValueRootIndex);
-    __ subp(rax, rdx);
-    __ Ret();
+    __ PushReturnAddressFrom(rcx);
+    __ TailCallRuntime(strict() ? Runtime::kStrictEquals : Runtime::kEquals);
   } else {
-    // Push arguments below the return address to prepare jump to builtin.
-    __ PopReturnAddressTo(rcx);
-    __ Push(rdx);
-    __ Push(rax);
     __ Push(Smi::FromInt(NegativeComparisonResult(cc)));
     __ PushReturnAddressFrom(rcx);
     __ TailCallRuntime(Runtime::kCompare);
   }
 
   __ bind(&miss);
   GenerateMiss(masm);
 }
 
 
@@ skipping 4293 matching lines @@
                            NULL);
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64