Add new HSeqStringGetChar instruction.

src/hydrogen-instructions.h

Index: src/hydrogen-instructions.h
diff --git a/src/hydrogen-instructions.h b/src/hydrogen-instructions.h
index 66050f1398c1da307365f11854be912f3a39afc3..15f307783b90718525ddd747f6a1d41fd0a30611 100644
--- a/src/hydrogen-instructions.h
+++ b/src/hydrogen-instructions.h
@@ -159,6 +159,7 @@ class LChunkBuilder;
   V(Return)                                    \
   V(Ror)                                       \
   V(Sar)                                       \
+  V(SeqStringGetChar)                          \
   V(SeqStringSetChar)                          \
   V(Shl)                                       \
   V(Shr)                                       \
@@ -7023,6 +7024,56 @@ class HDateField V8_FINAL : public HUnaryOperation {
 };
 
 
+class HSeqStringGetChar V8_FINAL : public HTemplateInstruction<2> {
+ public:
+  static HInstruction* New(Zone* zone,
+                           HValue* context,
+                           String::Encoding encoding,
+                           HValue* string,
+                           HValue* index);
+
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
+    return (index == 0) ? Representation::Tagged()
+                        : Representation::Integer32();
+  }
+
+  String::Encoding encoding() const { return encoding_; }
+  HValue* string() const { return OperandAt(0); }
+  HValue* index() const { return OperandAt(1); }
+
+  DECLARE_CONCRETE_INSTRUCTION(SeqStringGetChar)
+
+ protected:
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE {
+    return encoding() == HSeqStringGetChar::cast(other)->encoding();
+  }
+
+  virtual Range* InferRange(Zone* zone) V8_OVERRIDE {
+    if (encoding() == String::ONE_BYTE_ENCODING) {
+      return new(zone) Range(0, String::kMaxOneByteCharCode);
+    } else {
+      ASSERT_EQ(String::TWO_BYTE_ENCODING, encoding());
+      return  new(zone) Range(0, String::kMaxUtf16CodeUnit);
+    }
+  }
+
+ private:
+  HSeqStringGetChar(String::Encoding encoding,
+                    HValue* string,
+                    HValue* index) : encoding_(encoding) {
+    SetOperandAt(0, string);
+    SetOperandAt(1, index);
+    set_representation(Representation::Integer32());
+    SetFlag(kUseGVN);
+    SetGVNFlag(kDependsOnStringChars);
+  }
+
+  virtual bool IsDeletable() const V8_OVERRIDE { return true; }
+
+  String::Encoding encoding_;
+};
+
+
 class HSeqStringSetChar V8_FINAL : public HTemplateInstruction<3> {
  public:
   DECLARE_INSTRUCTION_FACTORY_P4(HSeqStringSetChar, String::Encoding,