diff --git a/clang/include/clang/AST/Comment.h b/clang/include/clang/AST/Comment.h
--- a/clang/include/clang/AST/Comment.h
+++ b/clang/include/clang/AST/Comment.h
@@ -1077,6 +1077,9 @@
   /// Can be true only if \c IsFunctionDecl is true.
   unsigned IsClassMethod : 1;
 
+  /// Is \c CommentDecl something we consider a "function" that's variadic.
+  unsigned IsVariadic : 1;
+
   void fill();
 
   DeclKind getKind() const LLVM_READONLY {
diff --git a/clang/lib/AST/Comment.cpp b/clang/lib/AST/Comment.cpp
--- a/clang/lib/AST/Comment.cpp
+++ b/clang/lib/AST/Comment.cpp
@@ -210,6 +210,7 @@
   IsObjCMethod = false;
   IsInstanceMethod = false;
   IsClassMethod = false;
+  IsVariadic = false;
   ParamVars = None;
   TemplateParameters = nullptr;
 
@@ -248,6 +249,7 @@
       IsInstanceMethod = MD->isInstance();
       IsClassMethod = !IsInstanceMethod;
     }
+    IsVariadic = FD->isVariadic();
     break;
   }
   case Decl::ObjCMethod: {
@@ -258,6 +260,7 @@
     IsObjCMethod = true;
     IsInstanceMethod = MD->isInstanceMethod();
     IsClassMethod = !IsInstanceMethod;
+    IsVariadic = MD->isVariadic();
     break;
   }
   case Decl::FunctionTemplate: {
@@ -268,6 +271,7 @@
     ParamVars = FD->parameters();
     ReturnType = FD->getReturnType();
     TemplateParameters = FTD->getTemplateParameters();
+    IsVariadic = FD->isVariadic();
     break;
   }
   case Decl::ClassTemplate: {
@@ -351,6 +355,8 @@
       Kind = FunctionKind;
       ParamVars = FTL.getParams();
       ReturnType = FTL.getReturnLoc().getType();
+      if (const auto *FPT = dyn_cast<FunctionProtoType>(FTL.getTypePtr()))
+        IsVariadic = FPT->isVariadic();
     }
   }
 
diff --git a/clang/lib/AST/CommentSema.cpp b/clang/lib/AST/CommentSema.cpp
--- a/clang/lib/AST/CommentSema.cpp
+++ b/clang/lib/AST/CommentSema.cpp
@@ -830,26 +830,11 @@
 }
 
 bool Sema::isFunctionOrMethodVariadic() {
-  if (!isFunctionDecl() || !ThisDeclInfo->CurrentDecl)
+  if (!ThisDeclInfo)
     return false;
-  if (const FunctionDecl *FD =
-        dyn_cast<FunctionDecl>(ThisDeclInfo->CurrentDecl))
-    return FD->isVariadic();
-  if (const FunctionTemplateDecl *FTD =
-        dyn_cast<FunctionTemplateDecl>(ThisDeclInfo->CurrentDecl))
-    return FTD->getTemplatedDecl()->isVariadic();
-  if (const ObjCMethodDecl *MD =
-        dyn_cast<ObjCMethodDecl>(ThisDeclInfo->CurrentDecl))
-    return MD->isVariadic();
-  if (const TypedefNameDecl *TD =
-          dyn_cast<TypedefNameDecl>(ThisDeclInfo->CurrentDecl)) {
-    QualType Type = TD->getUnderlyingType();
-    if (Type->isFunctionPointerType() || Type->isBlockPointerType())
-      Type = Type->getPointeeType();
-    if (const auto *FT = Type->getAs<FunctionProtoType>())
-      return FT->isVariadic();
-  }
-  return false;
+  if (!ThisDeclInfo->IsFilled)
+    inspectThisDecl();
+  return ThisDeclInfo->IsVariadic;
 }
 
 bool Sema::isObjCMethodDecl() {
diff --git a/clang/test/Sema/warn-documentation.cpp b/clang/test/Sema/warn-documentation.cpp
--- a/clang/test/Sema/warn-documentation.cpp
+++ b/clang/test/Sema/warn-documentation.cpp
@@ -1448,6 +1448,17 @@
  */
 using VariadicFnType2 = void (*)(int a, ...);
 
+/*!
+ * Function pointer type variable.
+ *
+ * @param a
+ * works
+ *
+ * @param ...
+ * now should work too.
+ */
+void (*variadicFnVar)(int a, ...);
+
 // expected-warning@+2 {{empty paragraph passed to '@note' command}}
 /**
 @note