Add some documentation.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72622 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/llvm/ADT/APFloat.h b/include/llvm/ADT/APFloat.h
index aebc6e6..1ff9241 100644
--- a/include/llvm/ADT/APFloat.h
+++ b/include/llvm/ADT/APFloat.h
@@ -188,8 +188,13 @@
     static APFloat getInf(const fltSemantics &Sem, bool Negative = false) {
       return APFloat(Sem, fcInfinity, Negative);
     }
+    /// getNaN - Factory for QNaN values.
+    ///
+    /// \param Negative - True iff the NaN generated should be negative.
+    /// \param type - The unspecified fill bits for creating the NaN, 0 by
+    /// default.
     static APFloat getNaN(const fltSemantics &Sem, bool Negative = false,
-                          long unsigned type=0) {
+                          unsigned type = 0) {
       return APFloat(Sem, fcNaN, Negative, type);
     }