Revert r4715.

src/x64/stub-cache-x64.cc

 // Copyright 2010 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 1130 matching lines @@
   } else {
     // Get the elements array of the object.
     __ movq(rbx, FieldOperand(rdx, JSArray::kElementsOffset));
 
     // Check that the elements are in fast mode (not dictionary).
     __ Cmp(FieldOperand(rbx, HeapObject::kMapOffset),
            Factory::fixed_array_map());
     __ j(not_equal, &miss);
 
     if (argc == 1) {  // Otherwise fall through to call builtin.
-      Label call_builtin, exit, with_write_barrier, attempt_to_grow_elements;
+      Label call_builtin, exit, with_rset_update, attempt_to_grow_elements;
 
       // Get the array's length into rax and calculate new length.
       __ movq(rax, FieldOperand(rdx, JSArray::kLengthOffset));
       STATIC_ASSERT(FixedArray::kMaxLength < Smi::kMaxValue);
       __ SmiAddConstant(rax, rax, Smi::FromInt(argc));
 
       // Get the element's length into rcx.
-      __ movq(rcx, FieldOperand(rbx, FixedArray::kLengthOffset));
+      __ movl(rcx, FieldOperand(rbx, FixedArray::kLengthOffset));
+      __ Integer32ToSmi(rcx, rcx);
 
       // Check if we could survive without allocation.
       __ SmiCompare(rax, rcx);
       __ j(greater, &attempt_to_grow_elements);
 
       // Save new length.
       __ movq(FieldOperand(rdx, JSArray::kLengthOffset), rax);
 
       // Push the element.
       __ movq(rcx, Operand(rsp, argc * kPointerSize));
       SmiIndex index =
           masm()->SmiToIndex(kScratchRegister, rax, times_pointer_size);
       __ lea(rdx, FieldOperand(rbx,
                                index.reg, index.scale,
                                FixedArray::kHeaderSize - argc * kPointerSize));
       __ movq(Operand(rdx, 0), rcx);
 
       // Check if value is a smi.
-      __ JumpIfNotSmi(rcx, &with_write_barrier);
+      __ JumpIfNotSmi(rcx, &with_rset_update);
 
       __ bind(&exit);
       __ ret((argc + 1) * kPointerSize);
 
-      __ bind(&with_write_barrier);
+      __ bind(&with_rset_update);
 
       __ InNewSpace(rbx, rcx, equal, &exit);
 
       RecordWriteStub stub(rbx, rdx, rcx);
       __ CallStub(&stub);
       __ ret((argc + 1) * kPointerSize);
 
       __ bind(&attempt_to_grow_elements);
       ExternalReference new_space_allocation_top =
           ExternalReference::new_space_allocation_top_address();
@@ skipping 27 matching lines @@
       // ... and fill the rest with holes.
       __ Move(kScratchRegister, Factory::the_hole_value());
       for (int i = 1; i < kAllocationDelta; i++) {
         __ movq(Operand(rdx, i * kPointerSize), kScratchRegister);
       }
 
       // Restore receiver to rdx as finish sequence assumes it's here.
       __ movq(rdx, Operand(rsp, (argc + 1) * kPointerSize));
 
       // Increment element's and array's sizes.
-      __ SmiAddConstant(FieldOperand(rbx, FixedArray::kLengthOffset),
-                        Smi::FromInt(kAllocationDelta));
+      __ addl(FieldOperand(rbx, FixedArray::kLengthOffset),
+              Immediate(kAllocationDelta));
       __ movq(FieldOperand(rdx, JSArray::kLengthOffset), rax);
 
-      // Elements are in new space, so write barrier is not required.
+      // Elements are in new space, so no remembered set updates are necessary.
       __ ret((argc + 1) * kPointerSize);
 
       __ bind(&call_builtin);
     }
 
     __ TailCallExternalReference(ExternalReference(Builtins::c_ArrayPush),
                                  argc + 1,
                                  1);
   }
 
@@ skipping 1145 matching lines @@
   // Return the generated code.
   return GetCode();
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64