Always tag number candidate as smi if it does not come from load-keyed.

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 4785 matching lines @@
       HLoadKeyed* load = HLoadKeyed::cast(value);
       if (load->UsesMustHandleHole()) {
         if (load->hole_mode() == ALLOW_RETURN_HOLE) {
           mode = NUMBER_CANDIDATE_IS_SMI_CONVERT_HOLE;
         } else {
           mode = NUMBER_CANDIDATE_IS_SMI_OR_HOLE;
         }
       } else {
         mode = NUMBER_CANDIDATE_IS_SMI;
       }
+    } else {
+      mode = NUMBER_CANDIDATE_IS_SMI;
     }
   }
 
   EmitNumberUntagD(input_reg, result_reg,
                    instr->hydrogen()->deoptimize_on_undefined(),
                    instr->hydrogen()->deoptimize_on_minus_zero(),
                    instr->environment(),
                    mode);
 }
 
@@ skipping 914 matching lines @@
                                FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64