Adapt Danno's Track Allocation Info idea to fast literals. When allocating a literal array,

src/x64/full-codegen-x64.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1685 matching lines @@
   } else if (length > FastCloneShallowArrayStub::kMaximumClonedLength) {
     __ CallRuntime(Runtime::kCreateArrayLiteralShallow, 3);
   } else {
     ASSERT(IsFastSmiOrObjectElementsKind(constant_elements_kind) ||
            FLAG_smi_only_arrays);
     // If the elements are already FAST_*_ELEMENTS, the boilerplate cannot
     // change, so it's possible to specialize the stub in advance.
     FastCloneShallowArrayStub::Mode mode = has_constant_fast_elements
         ? FastCloneShallowArrayStub::CLONE_ELEMENTS
         : FastCloneShallowArrayStub::CLONE_ANY_ELEMENTS;
+
+    // Tracking allocation info allows us to pre-transition later if it makes
+    // sense.
+    if (mode == FastCloneShallowArrayStub::CLONE_ANY_ELEMENTS &&
+        FLAG_track_allocation_sites) {
+      mode = FastCloneShallowArrayStub::
+          CLONE_ANY_ELEMENTS_WITH_ALLOCATION_SITE_INFO;
+    }
+
     FastCloneShallowArrayStub stub(mode, length);
     __ CallStub(&stub);
   }
 
   bool result_saved = false;  // Is the result saved to the stack?
 
   // Emit code to evaluate all the non-constant subexpressions and to store
   // them into the newly cloned array.
   for (int i = 0; i < length; i++) {
     Expression* subexpr = subexprs->at(i);
@@ skipping 2802 matching lines @@
   *context_length = 0;
   return previous_;
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64