Summary: This is a bit of refactoring required to be able to generate instruction in forward basic block. This, for instance, is a requirement for phi in loops.
Reviewers: bogner, chandlerc, echristo, dblaikie, joker.eph, Wallbraker
Differential Revision: http://reviews.llvm.org/D17050
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@260324 91177308-0d34-0410-b5e6-96231b3b80d8