Add LiveIntervals::addKillFlags() to recompute kill flags after register allocation.

This is a lot easier than trying to get kill flags right during live range
splitting and rematerialization.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125113 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed