Smi immediates are not supported on x64. Do not use it.

src/x64/lithium-codegen-x64.cc

 // Copyright 2013 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 1802 matching lines @@
 
 void LCodeGen::DoAddI(LAddI* instr) {
   LOperand* left = instr->left();
   LOperand* right = instr->right();
 
   Representation target_rep = instr->hydrogen()->representation();
   bool is_p = target_rep.IsSmi() || target_rep.IsExternal();
 
   if (LAddI::UseLea(instr->hydrogen()) && !left->Equals(instr->result())) {
     if (right->IsConstantOperand()) {
+      ASSERT(!target_rep.IsSmi());  // No support for smi-immediates.
       int32_t offset = ToInteger32(LConstantOperand::cast(right));
       if (is_p) {
         __ leap(ToRegister(instr->result()),
                 MemOperand(ToRegister(left), offset));
       } else {
         __ leal(ToRegister(instr->result()),
                 MemOperand(ToRegister(left), offset));
       }
     } else {
       Operand address(ToRegister(left), ToRegister(right), times_1, 0);
       if (is_p) {
         __ leap(ToRegister(instr->result()), address);
       } else {
         __ leal(ToRegister(instr->result()), address);
       }
     }
   } else {
     if (right->IsConstantOperand()) {
+      ASSERT(!target_rep.IsSmi());  // No support for smi-immediates.
       if (is_p) {
         __ addp(ToRegister(left),
                 Immediate(ToInteger32(LConstantOperand::cast(right))));
       } else {
         __ addl(ToRegister(left),
                 Immediate(ToInteger32(LConstantOperand::cast(right))));
       }
     } else if (right->IsRegister()) {
       if (is_p) {
         __ addp(ToRegister(left), ToRegister(right));
@@ skipping 3827 matching lines @@
   __ bind(deferred->exit());
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64