MIPS: Use SmiTst and TrySmiTag MacroAssembler instructions.

src/mips/stub-cache-mips.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 2298 matching lines @@
     GenerateGlobalReceiverCheck(Handle<JSObject>::cast(object), holder, name,
                                 &miss);
     GenerateLoadFunctionFromCell(cell, function, &miss);
   }
 
   // Load the (only) argument into v0.
   __ lw(v0, MemOperand(sp, 0 * kPointerSize));
 
   // If the argument is a smi, just return.
   STATIC_ASSERT(kSmiTag == 0);
-  __ And(t0, v0, Operand(kSmiTagMask));
+  __ SmiTst(v0, t0);
   __ DropAndRet(argc + 1, eq, t0, Operand(zero_reg));
 
   __ CheckMap(v0, a1, Heap::kHeapNumberMapRootIndex, &slow, DONT_DO_SMI_CHECK);
 
   Label wont_fit_smi, no_fpu_error, restore_fcsr_and_return;
 
   // If fpu is enabled, we use the floor instruction.
 
   // Load the HeapNumber value.
   __ ldc1(f0, FieldMemOperand(v0, HeapNumber::kValueOffset));
@@ skipping 853 matching lines @@
   // -----------------------------------
   TailCallBuiltin(masm, Builtins::kKeyedLoadIC_Miss);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_MIPS