XCore target: Fix llvm.eh.return and EH info register handling

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@201561 91177308-0d34-0410-b5e6-96231b3b80d8
XCore target: addMemOperand as necessary

BuildMI instructions were not including MachineMemOperand information.
This was discovered by 'SingleSource/Benchmarks/Stanford/Oscar' failing
due to a FrameIndex load incorrectly being hoisted by postra-machine-licm.
No other tests have been found to fail.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@201562 91177308-0d34-0410-b5e6-96231b3b80d8
XCore target: Handle common linkage

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@201563 91177308-0d34-0410-b5e6-96231b3b80d8