[turbofan] avoid xchg instruction on Intel

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 3273 matching lines @@
   __ JumpIfNotRoot(rcx, Heap::kBooleanMapRootIndex, &miss, miss_distance);
   __ JumpIfNotRoot(rbx, Heap::kBooleanMapRootIndex, &miss, miss_distance);
   if (op() != Token::EQ_STRICT && is_strong(strength())) {
     __ TailCallRuntime(Runtime::kThrowStrongModeImplicitConversion);
   } else {
     if (!Token::IsEqualityOp(op())) {
       __ movp(rax, FieldOperand(rax, Oddball::kToNumberOffset));
       __ AssertSmi(rax);
       __ movp(rdx, FieldOperand(rdx, Oddball::kToNumberOffset));
       __ AssertSmi(rdx);
-      __ xchgp(rax, rdx);
+      __ pushq(rax);
+      __ movq(rax, rdx);
+      __ popq(rdx);
     }
     __ subp(rax, rdx);
     __ Ret();
   }
 
   __ bind(&miss);
   GenerateMiss(masm);
 }
 
 
@@ skipping 2109 matching lines @@
                            kStackSpace, nullptr, return_value_operand, NULL);
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64