in functions which call __builtin_unwind_init()
__builtin_unwind_init() is an undocumented gcc intrinsic which has this effect,
and is used in libgcc_eh.
Goes part of the way toward fixing PR8541.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@183984 91177308-0d34-0410-b5e6-96231b3b80d8