Fix performance regression introduced by r12812.

src/regexp-stack.cc

 // Copyright 2009 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 33 matching lines @@
   regexp_stack_->Reset();
 }
 
 
 RegExpStack::RegExpStack()
     : isolate_(NULL) {
 }
 
 
 RegExpStack::~RegExpStack() {
+  thread_local_.Free();
 }
 
 
 char* RegExpStack::ArchiveStack(char* to) {
   size_t size = sizeof(thread_local_);
   memcpy(reinterpret_cast<void*>(to),
          &thread_local_,
          size);
   thread_local_ = ThreadLocal();
   return to + size;
 }
 
 
 char* RegExpStack::RestoreStack(char* from) {
   size_t size = sizeof(thread_local_);
   memcpy(&thread_local_, reinterpret_cast<void*>(from), size);
   return from + size;
 }
 
 
 void RegExpStack::Reset() {
-  if (thread_local_.memory_size_ >= kMinimumStackSize) {
+  if (thread_local_.memory_size_ > kMinimumStackSize) {
     DeleteArray(thread_local_.memory_);
     thread_local_ = ThreadLocal();
   }
 }
 
 
 void RegExpStack::ThreadLocal::Free() {
   if (memory_size_ > 0) {
     DeleteArray(memory_);
     Clear();
@@ skipping 16 matching lines @@
     }
     thread_local_.memory_ = new_memory;
     thread_local_.memory_size_ = size;
     thread_local_.limit_ = new_memory + kStackLimitSlack * kPointerSize;
   }
   return thread_local_.memory_ + thread_local_.memory_size_;
 }
 
 
 }}  // namespace v8::internal