Exclude function calls for functions which have return type nullptr_t from
-Wnull-conversion warning.

These functions are basically equivalent to other pointer returning fuctions
which are already excluded by -Wnull-conversion.

llvm-svn: 257231
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index cbdcb5e..0c4b59e 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -7047,6 +7047,10 @@
                         E->getExprLoc()))
     return;
 
+  // Don't warn on functions which have return type nullptr_t.
+  if (isa<CallExpr>(E))
+    return;
+
   // Check for NULL (GNUNull) or nullptr (CXX11_nullptr).
   const Expr::NullPointerConstantKind NullKind =
       E->isNullPointerConstant(S.Context, Expr::NPC_ValueDependentIsNotNull);