Fix few g++ 8 warning with non obvious copy object operations

Reviewers: dblaikie, dexonsmith	

Reviewed By: dblaikie

Differential Revision: https://reviews.llvm.org/D50296


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@339367 91177308-0d34-0410-b5e6-96231b3b80d8