It is temporary patch. We need to keep it in trunk, since it makes easer to test it on buildbots on different platforms.
Once we see stable MergeFunctions behaviour with satisfied perfomance, this patch will be removed.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191331 91177308-0d34-0410-b5e6-96231b3b80d8
