Add comment for SelectionDAGBuilder::SL field.

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
index fa6a6ba..0924939 100644 (file)
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
@@ -406,6 +406,8 @@ public:
     SelectionDAGBuilder *SDB;
   };
 
+  // Data related to deferred switch lowerings. Used to construct additional
+  // Basic Blocks in SelectionDAGISel::FinishBasicBlock.
   std::unique_ptr<SDAGSwitchLowering> SL;
 
   /// A StackProtectorDescriptor structure used to communicate stack protector