[hydrogen] optimize switch with string clauses

src/type-info.h

Index: src/type-info.h
diff --git a/src/type-info.h b/src/type-info.h
index 2c3543eafbe87bb87c6c46089a360f50092204d2..7c9c05ef087c9e3bdab1584071c56e5f80ea532a 100644
--- a/src/type-info.h
+++ b/src/type-info.h
@@ -64,6 +64,8 @@ class TypeInfo {
   static TypeInfo Integer32() { return TypeInfo(kInteger32); }
   // We know it's a Smi.
   static TypeInfo Smi() { return TypeInfo(kSmi); }
+  // We know it's a Symbol.
+  static TypeInfo Symbol() { return TypeInfo(kSymbol); }
   // We know it's a heap number.
   static TypeInfo Double() { return TypeInfo(kDouble); }
   // We know it's a string.
@@ -137,6 +139,16 @@ class TypeInfo {
     return ((type_ & kSmi) == kSmi);
   }
 
+  inline bool IsSymbol() {
+    ASSERT(type_ != kUninitialized);
+    return ((type_ & kSymbol) == kSymbol);
+  }
+
+  inline bool IsNonSymbol() {
+    ASSERT(type_ != kUninitialized);
+    return ((type_ & kSymbol) == kString);
+  }
+
   inline bool IsInteger32() {
     ASSERT(type_ != kUninitialized);
     return ((type_ & kInteger32) == kInteger32);
@@ -168,6 +180,7 @@ class TypeInfo {
       case kNumber: return "Number";
       case kInteger32: return "Integer32";
       case kSmi: return "Smi";
+      case kSymbol: return "Symbol";
       case kDouble: return "Double";
       case kString: return "String";
       case kNonPrimitive: return "Object";
@@ -186,6 +199,7 @@ class TypeInfo {
     kSmi = 0x17,           // 0010111
     kDouble = 0x19,        // 0011001
     kString = 0x30,        // 0110000
+    kSymbol = 0x32,        // 0110010
     kNonPrimitive = 0x40,  // 1000000
     kUninitialized = 0x7f  // 1111111
   };