introduce LTaggedToSmi

src/ia32/lithium-ia32.h

Index: src/ia32/lithium-ia32.h
diff --git a/src/ia32/lithium-ia32.h b/src/ia32/lithium-ia32.h
index 811700a544aa9767d00b637930323a81c2a62794..80dc2e37a0464ce5089c76444c66277c986878cc 100644
--- a/src/ia32/lithium-ia32.h
+++ b/src/ia32/lithium-ia32.h
@@ -165,6 +165,7 @@ class LCodeGen;
   V(StringCompareAndBranch)                     \
   V(SubI)                                       \
   V(TaggedToI)                                  \
+  V(TaggedToSmi)                                \
   V(ThisFunction)                               \
   V(ToFastProperties)                           \
   V(TransitionElementsKind)                     \
@@ -1993,6 +1994,8 @@ class LDoubleToSmi V8_FINAL : public LTemplateInstruction<1, 1, 0> {
 
   DECLARE_CONCRETE_INSTRUCTION(DoubleToSmi, "double-to-smi")
   DECLARE_HYDROGEN_ACCESSOR(UnaryOperation)
+
+  bool truncating() { return hydrogen()->CanTruncateToSmi(); }
 };
 
 
@@ -2014,6 +2017,23 @@ class LTaggedToI V8_FINAL : public LTemplateInstruction<1, 1, 1> {
 };
 
 
+class LTaggedToSmi V8_FINAL : public LTemplateInstruction<1, 1, 1> {
+ public:
+  LTaggedToSmi(LOperand* value, LOperand* temp) {
+    inputs_[0] = value;
+    temps_[0] = temp;
+  }
+
+  LOperand* value() { return inputs_[0]; }
+  LOperand* temp() { return temps_[0]; }
+
+  DECLARE_CONCRETE_INSTRUCTION(TaggedToSmi, "tagged-to-smi")
+  DECLARE_HYDROGEN_ACCESSOR(Change)
+
+  bool truncating() { return hydrogen()->CanTruncateToSmi(); }
+};
+
+
 class LSmiTag V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LSmiTag(LOperand* value) {