[DAG] Move BaseIndexOffset into separate Libarary. NFC.

Move BaseIndexOffset analysis out of DAGCombiner for use in other
files.

llvm-svn: 305921
diff --git a/llvm/lib/CodeGen/SelectionDAG/CMakeLists.txt b/llvm/lib/CodeGen/SelectionDAG/CMakeLists.txt
index a668ddb..ae9c5ad 100644
--- a/llvm/lib/CodeGen/SelectionDAG/CMakeLists.txt
+++ b/llvm/lib/CodeGen/SelectionDAG/CMakeLists.txt
@@ -17,6 +17,7 @@
   ScheduleDAGVLIW.cpp
   SelectionDAGBuilder.cpp
   SelectionDAG.cpp
+  SelectionDAGAddressAnalysis.cpp
   SelectionDAGDumper.cpp
   SelectionDAGISel.cpp
   SelectionDAGPrinter.cpp