AMDGPU: Error on calls from graphics shaders

In principle nothing should stop these from working, but
work is necessary to create an ABI for dealing with the stack
related registers.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@335829 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed