Make sure to clear the CodeGenMap after each basic block is selected to avoid

cross MBB pollution.

llvm-svn: 23470

llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp

@@ -87,6 +87,7 @@ namespace {
       DEBUG(BB->dump());
       // Select target instructions for the DAG.
       DAG.setRoot(Select(DAG.getRoot()));
+      CodeGenMap.clear();
       DAG.RemoveDeadNodes();
       
       // Emit machine code to BB.