80 col. comment.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@198653 91177308-0d34-0410-b5e6-96231b3b80d8
indvars: sink truncates outside the loop.

This is a follow up of the r198338 commit that added truncates for
lcssa phi nodes. Sinking the truncates below the phis cleans up the
loop and simplifies subsequent analysis within the indvars pass.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@198654 91177308-0d34-0410-b5e6-96231b3b80d8