I've observed that when React's profiling mode is enabled, updating the profiling fields [here](https://github.com/facebook/react/blob/1d25aa5787d4e19704c049c3cfa985d3b5190e0d/packages/react-reconciler/src/ReactProfilerTimer.js#L46) and [here](https://github.com/facebook/react/blob/1d25aa5787d4e19704c049c3cfa985d3b5190e0d/packages/react-reconciler/src/ReactProfilerTimer.js#L69-L71) during the _render_ phase seems to cause a significant deopt in [`getHostSibling`](https://github.com/facebook/react/blob/1d25aa5787d4e19704c049c3cfa985d3b5190e0d/packages/react-reconciler/src/ReactFiberCommitWork.js#L858-L898) during the _commit_ phase for Chrome only. (Neither Safari nor Firefox seem to be affected by this.)

I have created a repro case with inline annotations here:
https://github.com/bvaughn/react-profiling-v8-deopt-repro#about-this-repro-case

(Note that the above repo is private. Please tag me here if you need access.)
memoizedState: any,
  
  firstContextDependency: ContextDependency<mixed> | null,
  
  
  
  
  
  
  mode: TypeOfMode,
  
  effectTag: SideEffectTag,
  
  nextEffect: Fiber | null,
  
  
  
  firstEffect: Fiber | null,
  lastEffect: Fiber | null,
  
  
  expirationTime: ExpirationTime,
  
  childExpirationTime: ExpirationTime,
  
  
  
  alternate: Fiber | null,