[foldMemoryOperand()] Pass LiveIntervals to enable liveness check.

SystemZ (and probably other targets as well) can fold a memory operand
by changing the opcode into a new instruction that as a side-effect
also clobbers the CC-reg.

In order to do this, liveness of that reg must first be checked. When
LIS is passed, getRegUnit() can be called on it and the right
LiveRange is computed on demand.

Reviewed by Matthias Braun.
http://reviews.llvm.org/D19861

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@269026 91177308-0d34-0410-b5e6-96231b3b80d8
11 files changed