[RISCV] Codegen support for memory operations

This required the implementation of RISCVTargetInstrInfo::copyPhysReg. Support
for lowering global addresses follow in the next patch.

Differential Revision: https://reviews.llvm.org/D29934


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@317685 91177308-0d34-0410-b5e6-96231b3b80d8
6 files changed