[CodeGen] Skip over dbg-instr in twoaddr pass

A DBG_VALUE between a two-address instruction and a following COPY
would prevent rescheduleMIBelowKill optimization inside
TwoAddressInstructionPass.

Differential Revision: https://reviews.llvm.org/D55987

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@350289 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed