[hydrogen] optimize switch with string clauses

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 2fe55fd1efd2c21aada46d94648cf73d05b214db..7c0e6b3283e70f8a0c20bcf00a8ab4c4c5763af4 100644
--- a/src/ia32/lithium-ia32.h
+++ b/src/ia32/lithium-ia32.h
@@ -103,8 +103,10 @@ class LCodeGen;
   V(IsConstructCallAndBranch)                   \
   V(IsNilAndBranch)                             \
   V(IsObjectAndBranch)                          \
+  V(IsStringAndBranch)                          \
   V(IsSmiAndBranch)                             \
   V(IsUndetectableAndBranch)                    \
+  V(StringCompareAndBranch)                    \
   V(JSArrayLength)                              \
   V(Label)                                      \
   V(LazyBailout)                                \
@@ -633,6 +635,19 @@ class LIsObjectAndBranch: public LControlInstruction<1, 1> {
 };
 
 
+class LIsStringAndBranch: public LControlInstruction<1, 1> {
+ public:
+  LIsStringAndBranch(LOperand* value, LOperand* temp) {
+    inputs_[0] = value;
+    temps_[0] = temp;
+  }
+
+  DECLARE_CONCRETE_INSTRUCTION(IsStringAndBranch, "is-string-and-branch")
+
+  virtual void PrintDataTo(StringStream* stream);
+};
+
+
 class LIsSmiAndBranch: public LControlInstruction<1, 0> {
  public:
   explicit LIsSmiAndBranch(LOperand* value) {
@@ -660,6 +675,24 @@ class LIsUndetectableAndBranch: public LControlInstruction<1, 1> {
 };
 
 
+class LStringCompareAndBranch: public LControlInstruction<3, 0> {
+ public:
+  LStringCompareAndBranch(LOperand* context, LOperand* left, LOperand* right) {
+    inputs_[0] = context;
+    inputs_[1] = left;
+    inputs_[2] = right;
+  }
+
+  DECLARE_CONCRETE_INSTRUCTION(StringCompareAndBranch,
+                               "compare-generic-and-branch")
+  DECLARE_HYDROGEN_ACCESSOR(StringCompareAndBranch)
+
+  virtual void PrintDataTo(StringStream* stream);
+
+  Token::Value op() const { return hydrogen()->token(); }
+};
+
+
 class LHasInstanceTypeAndBranch: public LControlInstruction<1, 1> {
  public:
   LHasInstanceTypeAndBranch(LOperand* value, LOperand* temp) {