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

src/x64/macro-assembler-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 4591 matching lines @@
   // object we've reached through the prototype chain.
   cmpq(empty_fixed_array_value,
        FieldOperand(rcx, JSObject::kElementsOffset));
   j(not_equal, call_runtime);
 
   movq(rcx, FieldOperand(rbx, Map::kPrototypeOffset));
   cmpq(rcx, null_value);
   j(not_equal, &next);
 }
 
+void MacroAssembler::TestJSArrayForAllocationSiteInfo(
+    Register receiver_reg,
+    Register scratch_reg,
+    Label* allocation_info_present) {
+  Label no_info_available;
+  ExternalReference new_space_start =
+      ExternalReference::new_space_start(isolate());
+  ExternalReference new_space_allocation_top =
+      ExternalReference::new_space_allocation_top_address(isolate());
+
+  lea(scratch_reg, Operand(receiver_reg,
+                           JSArray::kSize + AllocationSiteInfo::kSize));
+  movq(kScratchRegister, new_space_start);
+  cmpq(scratch_reg, kScratchRegister);
+  j(less, &no_info_available);
+  cmpq(scratch_reg, ExternalOperand(new_space_allocation_top));
+  j(greater_equal, &no_info_available);
+  CompareRoot(MemOperand(scratch_reg, 0),
+              Heap::kAllocationSiteInfoMapRootIndex);
+  j(equal, allocation_info_present);
+  bind(&no_info_available);
+}
+
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64