[LoopUnrolling] Fix a bug introduced in r259869 (PR26688).

The issue was that we only required LCSSA rebuilding if the immediate
parent-loop had values used outside of it. The fix is to enaable the
same logic for all outer loops, not only immediate parent.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@261575 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed