[hydrogen] optimize switch with string clauses

src/type-info.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 342 matching lines @@
   if (!code->is_compare_ic_stub()) return unknown;
 
   CompareIC::State state = static_cast<CompareIC::State>(code->compare_state());
   switch (state) {
     case CompareIC::UNINITIALIZED:
       // Uninitialized means never executed.
       // TODO(fschneider): Introduce a separate value for never-executed ICs.
       return unknown;
     case CompareIC::SMIS:
       return TypeInfo::Smi();
+    case CompareIC::STRINGS:
+      return TypeInfo::String();
+    case CompareIC::SYMBOLS:
+      return TypeInfo::Symbol();
     case CompareIC::HEAP_NUMBERS:
       return TypeInfo::Number();
     case CompareIC::OBJECTS:
       // TODO(kasperl): We really need a type for JS objects here.
       return TypeInfo::NonPrimitive();
     case CompareIC::GENERIC:
     default:
       return unknown;
   }
 }
@@ skipping 191 matching lines @@
   USE(maybe_result);
 #ifdef DEBUG
   Object* result = NULL;
   // Dictionary has been allocated with sufficient size for all elements.
   ASSERT(maybe_result->ToObject(&result));
   ASSERT(*dictionary_ == result);
 #endif
 }
 
 } }  // namespace v8::internal