This allows SCEV users to effectively calculate trip count.
LSR later on transforms back integer IVs to floating point IVs
later on to avoid int-to-float casts inside the loop.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@58625 91177308-0d34-0410-b5e6-96231b3b80d8