Clean ups for loop deletion based on Chris' feedback.

Also, use SCEV to determine the trip count of the loop, which is more powerful
and accurate that Loop::getTripCount.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51179 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed