[LV] Swap A and B in interleaved access analysis (NFC)

This patch swaps A and B in the interleaved access analysis and clarifies
related comments. The algorithm is more intuitive if we let access A precede
access B in program order rather than the reverse. This change was requested in
the review of D19984.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@275567 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed