- Revert parts of r39731 as they cause conflicting results.

runtime/vm/raw_object.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_RAW_OBJECT_H_
 #define VM_RAW_OBJECT_H_
 
 #include "platform/assert.h"
 #include "vm/atomic.h"
 #include "vm/globals.h"
@@ skipping 312 matching lines @@
     return MarkBit::decode(ptr()->tags_);
   }
   void SetMarkBit() {
     ASSERT(!IsMarked());
     uword tags = ptr()->tags_;
     ptr()->tags_ = MarkBit::update(true, tags);
   }
   void ClearMarkBit() {
     ASSERT(IsMarked());
     uword tags = ptr()->tags_;
-    uword old_tags;
-    do {
-      old_tags = tags;
-      uword new_tags = MarkBit::update(false, old_tags);
-      tags = AtomicOperations::CompareAndSwapWord(
-          &ptr()->tags_, old_tags, new_tags);
-    } while (tags != old_tags);
+    ptr()->tags_ = MarkBit::update(false, tags);
   }
 
   // Support for GC watched bit.
   bool IsWatched() const {
     return WatchedBit::decode(ptr()->tags_);
   }
   void SetWatchedBit() {
     ASSERT(!IsWatched());
     uword tags = ptr()->tags_;
     ptr()->tags_ = WatchedBit::update(true, tags);
@@ skipping 32 matching lines @@
     } while (tags != old_tags);
   }
 
   // Support for GC remembered bit.
   bool IsRemembered() const {
     return RememberedBit::decode(ptr()->tags_);
   }
   void SetRememberedBit() {
     ASSERT(!IsRemembered());
     uword tags = ptr()->tags_;
-    uword old_tags;
-    do {
-      old_tags = tags;
-      uword new_tags = RememberedBit::update(true, old_tags);
-      tags = AtomicOperations::CompareAndSwapWord(
-          &ptr()->tags_, old_tags, new_tags);
-    } while (tags != old_tags);
+    ptr()->tags_ = RememberedBit::update(true, tags);
   }
   void ClearRememberedBit() {
     uword tags = ptr()->tags_;
-    uword old_tags;
-    do {
-      old_tags = tags;
-      uword new_tags = RememberedBit::update(false, old_tags);
-      tags = AtomicOperations::CompareAndSwapWord(
-          &ptr()->tags_, old_tags, new_tags);
-    } while (tags != old_tags);
+    ptr()->tags_ = RememberedBit::update(false, tags);
   }
 
   bool IsDartInstance() {
     return (!IsHeapObject() || (GetClassId() >= kInstanceCid));
   }
   bool IsFreeListElement() {
     return ((GetClassId() == kFreeListElement));
   }
 
   intptr_t Size() const {
@@ skipping 1609 matching lines @@
   COMPILE_ASSERT(kExternalTypedDataInt8ArrayCid ==
                  kTypedDataInt8ArrayViewCid + 15);
   COMPILE_ASSERT(kByteBufferCid == kExternalTypedDataInt8ArrayCid + 14);
   COMPILE_ASSERT(kNullCid == kByteBufferCid + 1);
   return (kNullCid - kTypedDataInt8ArrayCid);
 }
 
 }  // namespace dart
 
 #endif  // VM_RAW_OBJECT_H_