diff --git a/clang/lib/Parse/ParseTentative.cpp b/clang/lib/Parse/ParseTentative.cpp
index 997d01076b90..81abdb884abd 100644
--- a/clang/lib/Parse/ParseTentative.cpp
+++ b/clang/lib/Parse/ParseTentative.cpp
@@ -1119,10 +1119,11 @@ bool Parser::isCXXFunctionDeclarator(bool warnIfAmbiguous) {
 ///   parameter-declaration-list ',' parameter-declaration
 ///
 /// parameter-declaration:
-///   decl-specifier-seq declarator
-///   decl-specifier-seq declarator '=' assignment-expression
-///   decl-specifier-seq abstract-declarator[opt]
-///   decl-specifier-seq abstract-declarator[opt] '=' assignment-expression
+///   decl-specifier-seq declarator attributes[opt]
+///   decl-specifier-seq declarator attributes[opt] '=' assignment-expression
+///   decl-specifier-seq abstract-declarator[opt] attributes[opt]
+///   decl-specifier-seq abstract-declarator[opt] attributes[opt]
+///     '=' assignment-expression
 ///
 Parser::TPResult Parser::TryParseParameterDeclarationClause() {
 
@@ -1157,6 +1158,10 @@ Parser::TPResult Parser::TryParseParameterDeclarationClause() {
     if (TPR != TPResult::Ambiguous())
       return TPR;
 
+    // [GNU] attributes[opt]
+    if (Tok.is(tok::kw___attribute))
+      return TPResult::True();
+
     if (Tok.is(tok::equal)) {
       // '=' assignment-expression
       // Parse through assignment-expression.
diff --git a/clang/test/SemaCXX/dcl_ambig_res.cpp b/clang/test/SemaCXX/dcl_ambig_res.cpp
index f0ba2978e8d7..fa71b11ba160 100644
--- a/clang/test/SemaCXX/dcl_ambig_res.cpp
+++ b/clang/test/SemaCXX/dcl_ambig_res.cpp
@@ -71,3 +71,6 @@ struct S5 {
 int foo8() {
   int v(int(S5::value)); // expected-warning{{disambiguated}} expected-error{{parameter declarator cannot be qualified}}
 }
+
+template<typename T>
+void rdar8739801( void (T::*)( void ) __attribute__((unused)) );