[IRTranslator] Update getOrCreateVReg API to use references.
A value that we want to keep in a virtual register cannot be null.
Reflect that in the API.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@263263 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed