This can happen if:
* It is present in a comdat in one file.
* It is not present in the comdat of the file that is kept.
* Is is not used.
This should fix the LTO boostrap.
Thanks to Takumi NAKAMURA for setting up the bot!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225983 91177308-0d34-0410-b5e6-96231b3b80d8