Fix comments.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31414 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/llvm/CodeGen/SelectionDAGNodes.h b/include/llvm/CodeGen/SelectionDAGNodes.h
index 9f56e17..1ed4dc4 100644
--- a/include/llvm/CodeGen/SelectionDAGNodes.h
+++ b/include/llvm/CodeGen/SelectionDAGNodes.h
@@ -809,13 +809,18 @@
   /// operation.
   bool hasNUsesOfValue(unsigned NUses, unsigned Value) const;
 
-  // isOnlyUse - Return true if this node is the only use of N.
+  /// isOnlyUse - Return true if this node is the only use of N.
+  ///
   bool isOnlyUse(SDNode *N) const;
 
-  // isOperand - Return true if this node is an operand of N.
+  /// isOperand - Return true if this node is an operand of N.
+  ///
   bool isOperand(SDNode *N) const;
 
-  // isPredecessor - Return true if this node is a predecessor of N.
+  /// isPredecessor - Return true if this node is a predecessor of N. This node
+  /// is either an operand of N or it can be reached by recursively traversing
+  /// up the operands.
+  /// NOTE: this is an expensive method. Use it carefully.
   bool isPredecessor(SDNode *N) const;
 
   /// getNumOperands - Return the number of values used by this operation.