[PATCH] SCEV incorrectly marks certain expressions as nsw

[Sanjoy Das]

> I think the later check, which is what you have in this patch, preserves the original optimization (which unfortunately has no unit tests because it only affects LSR).

I'm not sure I understand what the "original optimization" is in this
context.  I assume the previous change you're talking about is this:
http://reviews.llvm.org/D7331 -- that's a separate fix as far as I can
tell.

-- Sanjoy