Don't break the IV update in TLI::SimplifySetCC().

LSR always tries to make the ICmp in the loop latch use the incremented
induction variable. This allows the induction variable to be kept in a
single register.

When the induction variable limit is equal to the stride,
SimplifySetCC() would break LSR's hard work by transforming:

   (icmp (add iv, stride), stride) --> (cmp iv, 0)

This forced us to use lea for the IC update, preventing the simpler
incl+cmp.

<rdar://problem/7643606>
<rdar://problem/11184260>

llvm-svn: 154119