Put store buffer verification behind a flag.

src/store-buffer.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 372 matching lines @@
         slot_address += kPointerSize;
       }
     }
   }
 }
 #endif
 
 
 void StoreBuffer::Verify() {
 #ifdef DEBUG
-  VerifyPointers(heap_->old_pointer_space(),
-                 &StoreBuffer::FindPointersToNewSpaceInRegion);
-  VerifyPointers(heap_->map_space(),
-                 &StoreBuffer::FindPointersToNewSpaceInMapsRegion);
-  VerifyPointers(heap_->lo_space());
+  if (FLAG_enable_slow_asserts || FLAG_verify_heap) {
+    VerifyPointers(heap_->old_pointer_space(),
+                   &StoreBuffer::FindPointersToNewSpaceInRegion);
+    VerifyPointers(heap_->map_space(),
+                   &StoreBuffer::FindPointersToNewSpaceInMapsRegion);
+    VerifyPointers(heap_->lo_space());
+  }
 #endif
 }
 
 
 void StoreBuffer::GCEpilogue() {
   during_gc_ = false;
   Verify();
 }
 
 
@@ skipping 277 matching lines @@
 }
 
 
 void StoreBuffer::CheckForFullBuffer() {
   if (old_limit_ - old_top_ < kStoreBufferSize * 2) {
     HandleFullness();
   }
 }
 
 } }  // namespace v8::internal