- Splitted out some parts of R600 target to separate modules/headers.
- Reduced some include lists in headers.
- Minor forward declarations, redundant includes and flags in GCNSubtarget cleanup.
Drive by only.
FWIW, I would recommend static, or anonymous namespaces rather than inline.
New "R600ISelDAGToDAG.cpp" uses class AMDGPUDAGToDAGISel declared below in the header.