This target hook is intended to replace copyRegToReg entirely, but for now it
calls copyRegToReg.
Any remaining calls to copyRegToReg wil be replaced by COPY instructions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@107854 91177308-0d34-0410-b5e6-96231b3b80d8