Refactor elements kind conversion.

src/x64/ic-x64.cc

Index: src/x64/ic-x64.cc
diff --git a/src/x64/ic-x64.cc b/src/x64/ic-x64.cc
index c398723ab1927fa52a15f856867acdff1fa91f06..87d286738aacaa56e339dd34844478b84c1a871d 100644
--- a/src/x64/ic-x64.cc
+++ b/src/x64/ic-x64.cc
@@ -1603,15 +1603,22 @@ void KeyedStoreIC::GenerateMiss(MacroAssembler* masm, bool force_generic) {
 
 void KeyedStoreIC::GenerateTransitionElementsSmiToDouble(MacroAssembler* masm) {
   // ----------- S t a t e -------------
+  //  -- rbx     : target map
   //  -- rdx     : receiver
   //  -- rsp[0]  : return address
   // -----------------------------------
   // Must return the modified receiver in eax.
+  if (!FLAG_trace_elements_transitions) {
+    Label fail;
+    ElementsTransitionGenerator::GenerateSmiOnlyToDouble(masm, &fail);
+    __ movq(rax, rdx);
+    __ Ret();
+    __ bind(&fail);
+  }
 
   __ pop(rbx);
   __ push(rdx);
   __ push(rbx);  // return address
-
   __ TailCallRuntime(Runtime::kTransitionElementsSmiToDouble, 1, 1);
 }
 
@@ -1619,15 +1626,22 @@ void KeyedStoreIC::GenerateTransitionElementsSmiToDouble(MacroAssembler* masm) {
 void KeyedStoreIC::GenerateTransitionElementsDoubleToObject(
     MacroAssembler* masm) {
   // ----------- S t a t e -------------
+  //  -- rbx     : target map
   //  -- rdx     : receiver
   //  -- rsp[0]  : return address
   // -----------------------------------
   // Must return the modified receiver in eax.
+  if (!FLAG_trace_elements_transitions) {
+    Label fail;
+    ElementsTransitionGenerator::GenerateDoubleToObject(masm, &fail);
+    __ movq(rax, rdx);
+    __ Ret();
+    __ bind(&fail);
+  }
 
   __ pop(rbx);
   __ push(rdx);
   __ push(rbx);  // return address
-
   __ TailCallRuntime(Runtime::kTransitionElementsDoubleToObject, 1, 1);
 }