Tag length of FixedArrayBase and smi-array[x] as smi representation

src/x64/lithium-codegen-x64.cc

Index: src/x64/lithium-codegen-x64.cc
diff --git a/src/x64/lithium-codegen-x64.cc b/src/x64/lithium-codegen-x64.cc
index a3f210ec07b18cde21579d65559141c34681a2c7..dd24c7bfd1f005a9e551ff7b992c0fec39fb8fbe 100644
--- a/src/x64/lithium-codegen-x64.cc
+++ b/src/x64/lithium-codegen-x64.cc
@@ -4911,6 +4911,13 @@ void LCodeGen::DoDoubleToSmi(LDoubleToSmi* instr) {
 }
 
 
+void LCodeGen::DoCheckSmiAndReturn(LCheckSmiAndReturn* instr) {
+  LOperand* input = instr->value();
+  Condition cc = masm()->CheckSmi(ToRegister(input));
+  DeoptimizeIf(NegateCondition(cc), instr->environment());
+}
+
+
 void LCodeGen::DoCheckSmi(LCheckSmi* instr) {
   LOperand* input = instr->value();
   Condition cc = masm()->CheckSmi(ToRegister(input));