diff --git a/src/x64/codegen-x64.cc b/src/x64/codegen-x64.cc
index 8dfd7cc857..48b396893f 100644
--- a/src/x64/codegen-x64.cc
+++ b/src/x64/codegen-x64.cc
@@ -3144,11 +3144,9 @@ void CodeGenerator::VisitCompareOperation(CompareOperation* node) {
       __ testb(FieldOperand(kScratchRegister, Map::kBitFieldOffset),
                Immediate(1 << Map::kIsUndetectable));
       destination()->false_target()->Branch(not_zero);
-      __ movb(kScratchRegister,
-              FieldOperand(kScratchRegister, Map::kInstanceTypeOffset));
-      __ cmpb(kScratchRegister, Immediate(FIRST_JS_OBJECT_TYPE));
+      __ CmpInstanceType(kScratchRegister, FIRST_JS_OBJECT_TYPE);
       destination()->false_target()->Branch(below);
-      __ cmpb(kScratchRegister, Immediate(LAST_JS_OBJECT_TYPE));
+      __ CmpInstanceType(kScratchRegister, LAST_JS_OBJECT_TYPE);
       answer.Unuse();
       destination()->Split(below_equal);
     } else {
@@ -3393,27 +3391,22 @@ void CodeGenerator::GenerateClassOf(ZoneList<Expression*>* args) {
 
   // Check that the object is a JS object but take special care of JS
   // functions to make sure they have 'Function' as their class.
-  { Result tmp = allocator()->Allocate();
-    __ movq(obj.reg(), FieldOperand(obj.reg(), HeapObject::kMapOffset));
-    __ movb(tmp.reg(), FieldOperand(obj.reg(), Map::kInstanceTypeOffset));
-    __ cmpb(tmp.reg(), Immediate(FIRST_JS_OBJECT_TYPE));
-    null.Branch(less);
 
-    // As long as JS_FUNCTION_TYPE is the last instance type and it is
-    // right after LAST_JS_OBJECT_TYPE, we can avoid checking for
-    // LAST_JS_OBJECT_TYPE.
-    ASSERT(LAST_TYPE == JS_FUNCTION_TYPE);
-    ASSERT(JS_FUNCTION_TYPE == LAST_JS_OBJECT_TYPE + 1);
-    __ cmpb(tmp.reg(), Immediate(JS_FUNCTION_TYPE));
-    function.Branch(equal);
-  }
+  __ CmpObjectType(obj.reg(), FIRST_JS_OBJECT_TYPE, obj.reg());
+  null.Branch(less);
+
+  // As long as JS_FUNCTION_TYPE is the last instance type and it is
+  // right after LAST_JS_OBJECT_TYPE, we can avoid checking for
+  // LAST_JS_OBJECT_TYPE.
+  ASSERT(LAST_TYPE == JS_FUNCTION_TYPE);
+  ASSERT(JS_FUNCTION_TYPE == LAST_JS_OBJECT_TYPE + 1);
+  __ CmpInstanceType(obj.reg(), JS_FUNCTION_TYPE);
+  function.Branch(equal);
 
   // Check if the constructor in the map is a function.
-  { Result tmp = allocator()->Allocate();
-    __ movq(obj.reg(), FieldOperand(obj.reg(), Map::kConstructorOffset));
-    __ CmpObjectType(obj.reg(), JS_FUNCTION_TYPE, tmp.reg());
-    non_function_constructor.Branch(not_equal);
-  }
+  __ movq(obj.reg(), FieldOperand(obj.reg(), Map::kConstructorOffset));
+  __ CmpObjectType(obj.reg(), JS_FUNCTION_TYPE, kScratchRegister);
+  non_function_constructor.Branch(not_equal);
 
   // The obj register now contains the constructor function. Grab the
   // instance class name from there.
@@ -5428,6 +5421,7 @@ void ToBooleanStub::Generate(MacroAssembler* masm) {
   __ j(equal, &false_result);
 
   // Get the map and type of the heap object.
+  // We don't use CmpObjectType because we manipulate the type field.
   __ movq(rdx, FieldOperand(rax, HeapObject::kMapOffset));
   __ movzxbq(rcx, FieldOperand(rdx, Map::kInstanceTypeOffset));
 
diff --git a/src/x64/ic-x64.cc b/src/x64/ic-x64.cc
index abaffb338d..7b8699f6d3 100644
--- a/src/x64/ic-x64.cc
+++ b/src/x64/ic-x64.cc
@@ -212,11 +212,9 @@ void CallIC::Generate(MacroAssembler* masm,
   __ movq(rdx, Operand(rsp, (argc + 1) * kPointerSize));  // receiver
   __ testl(rdx, Immediate(kSmiTagMask));
   __ j(zero, &invoke);
-  __ movq(rcx, FieldOperand(rdx, HeapObject::kMapOffset));
-  __ movzxbq(rcx, FieldOperand(rcx, Map::kInstanceTypeOffset));
-  __ cmpq(rcx, Immediate(static_cast<int8_t>(JS_GLOBAL_OBJECT_TYPE)));
+  __ CmpObjectType(rdx, JS_GLOBAL_OBJECT_TYPE, rcx);
   __ j(equal, &global);
-  __ cmpq(rcx, Immediate(static_cast<int8_t>(JS_BUILTINS_OBJECT_TYPE)));
+  __ CmpInstanceType(rcx, JS_BUILTINS_OBJECT_TYPE);
   __ j(not_equal, &invoke);
 
   // Patch the receiver on the stack.