Responding to review feedback from http://reviews.llvm.org/D9585
1) Remove a variable shadow by converting the outer loop to a range for loop. We never really used the 'i' variable which was being shadowed.
2) Reduce DominatorTree recalculations by passing the DT to SplitEdge.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237212 91177308-0d34-0410-b5e6-96231b3b80d8