Merge "Avoid generating dead code on frame enter/exit. This includes stack operations and, on x86, call/pop to read PC."
am: 8189b0b4e1

* commit '8189b0b4e1f14420382b87e900dd6a50aec9c2de':
  Avoid generating dead code on frame enter/exit. This includes stack operations and, on x86, call/pop to read PC.