Make sure transitioned arrays efficiently call builtin Array functions

src/ia32/stub-cache-ia32.cc

Index: src/ia32/stub-cache-ia32.cc
diff --git a/src/ia32/stub-cache-ia32.cc b/src/ia32/stub-cache-ia32.cc
index c27a60fd06573ae7fc91c30fd343886f3772d453..051a8177eac0f10bf168ed6324f50c5947766df4 100644
--- a/src/ia32/stub-cache-ia32.cc
+++ b/src/ia32/stub-cache-ia32.cc
@@ -878,13 +878,10 @@ Register StubCompiler::CheckPrototypes(Handle<JSObject> object,
       if (in_new_space) {
         // Save the map in scratch1 for later.
         __ mov(scratch1, FieldOperand(reg, HeapObject::kMapOffset));
-        __ cmp(scratch1, Immediate(current_map));
-      } else {
-        __ cmp(FieldOperand(reg, HeapObject::kMapOffset),
-               Immediate(current_map));
       }
-      // Branch on the result of the map check.
-      __ j(not_equal, miss);
+      __ CheckMap(reg, current_map, miss, DONT_DO_SMI_CHECK,
+                  ALLOW_ELEMENT_TRANSITION_MAPS);
+
       // Check access rights to the global object.  This has to happen after
       // the map check so that we know that the object is actually a global
       // object.
@@ -916,9 +913,8 @@ Register StubCompiler::CheckPrototypes(Handle<JSObject> object,
   LOG(isolate(), IntEvent("check-maps-depth", depth + 1));
 
   // Check the holder map.
-  __ cmp(FieldOperand(reg, HeapObject::kMapOffset),
-         Immediate(Handle<Map>(holder->map())));
-  __ j(not_equal, miss);
+  __ CheckMap(reg, Handle<Map>(holder->map()),
+              miss, DONT_DO_SMI_CHECK, ALLOW_ELEMENT_TRANSITION_MAPS);
 
   // Perform security check for access to the global object.
   ASSERT(holder->IsJSGlobalProxy() || !holder->IsAccessCheckNeeded());