MIPS: Eliminate redundant smi checks

src/mips/lithium-mips.cc

Index: src/mips/lithium-mips.cc
diff --git a/src/mips/lithium-mips.cc b/src/mips/lithium-mips.cc
index 8b8d0ccc4cf0dda0086889c0faead8c58f146f96..842001ddf260e0f628ac3c08ad8ec82f253d53e9 100644
--- a/src/mips/lithium-mips.cc
+++ b/src/mips/lithium-mips.cc
@@ -1647,10 +1647,9 @@ LInstruction* LChunkBuilder::DoChange(HChange* instr) {
     } else {
       ASSERT(to.IsInteger32());
       LOperand* value = UseRegisterAtStart(instr->value());
-      bool needs_check = !instr->value()->type().IsSmi();
       LInstruction* res = NULL;
-      if (!needs_check) {
-        res = DefineAsRegister(new(zone()) LSmiUntag(value, needs_check));
+      if (instr->value()->type().IsSmi()) {
+        res = DefineAsRegister(new(zone()) LSmiUntag(value, false));
       } else {
         LOperand* temp1 = TempRegister();
         LOperand* temp2 = instr->CanTruncateToInt32() ? TempRegister()