Don't check symbol literals for being symbols.

src/hydrogen-instructions.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 766 matching lines @@
 
 void HChange::PrintDataTo(StringStream* stream) {
   HUnaryOperation::PrintDataTo(stream);
   stream->Add(" %s to %s", from_.Mnemonic(), to().Mnemonic());
 
   if (CanTruncateToInt32()) stream->Add(" truncating-int32");
   if (CheckFlag(kBailoutOnMinusZero)) stream->Add(" -0?");
 }
 
 
+HValue* HCheckInstanceType::Canonicalize() {
+  if (check_ == IS_STRING &&
+      !value()->type().IsUninitialized() &&
+      value()->type().IsString()) {
+    return NULL;
+  }
+  if (check_ == IS_SYMBOL &&
+      value()->IsConstant() &&
+      HConstant::cast(value())->handle()->IsSymbol()) {
+    return NULL;
+  }
+  return this;
+}
+
+
 void HCheckInstanceType::GetCheckInterval(InstanceType* first,
                                           InstanceType* last) {
   ASSERT(is_interval_check());
   switch (check_) {
     case IS_SPEC_OBJECT:
       *first = FIRST_SPEC_OBJECT_TYPE;
       *last = LAST_SPEC_OBJECT_TYPE;
       return;
     case IS_JS_ARRAY:
       *first = *last = JS_ARRAY_TYPE;
@@ skipping 1000 matching lines @@
 
 
 void HCheckPrototypeMaps::Verify() {
   HInstruction::Verify();
   ASSERT(HasNoUses());
 }
 
 #endif
 
 } }  // namespace v8::internal