This is a work in progress. So far we have some basic loop analysis to help
determine where it is useful to split a live range around a loop.
The actual loop splitting code from Splitter.cpp is also going to move in here.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@108842 91177308-0d34-0410-b5e6-96231b3b80d8
