diff --git a/clang/include/clang/Serialization/ASTWriter.h b/clang/include/clang/Serialization/ASTWriter.h
index 6cbf3dd20017a7..57d001e571efc6 100644
--- a/clang/include/clang/Serialization/ASTWriter.h
+++ b/clang/include/clang/Serialization/ASTWriter.h
@@ -477,7 +477,6 @@ class ASTWriter : public ASTDeserializationListener,
                                      bool isModule);
 
   unsigned TypeExtQualAbbrev = 0;
-  unsigned TypeFunctionProtoAbbrev = 0;
   void WriteTypeAbbrevs();
   void WriteType(QualType T);
 
@@ -682,10 +681,6 @@ class ASTWriter : public ASTDeserializationListener,
     return TypeExtQualAbbrev;
   }
 
-  unsigned getTypeFunctionProtoAbbrev() const {
-    return TypeFunctionProtoAbbrev;
-  }
-
   unsigned getDeclParmVarAbbrev() const { return DeclParmVarAbbrev; }
   unsigned getDeclRecordAbbrev() const { return DeclRecordAbbrev; }
   unsigned getDeclTypedefAbbrev() const { return DeclTypedefAbbrev; }
diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index 4e8542e13ff700..189d1a914ec31a 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -598,30 +598,6 @@ void ASTWriter::WriteTypeAbbrevs() {
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Type
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 3));   // Quals
   TypeExtQualAbbrev = Stream.EmitAbbrev(std::move(Abv));
-
-  // Abbreviation for TYPE_FUNCTION_PROTO
-  Abv = std::make_shared<BitCodeAbbrev>();
-  Abv->Add(BitCodeAbbrevOp(serialization::TYPE_FUNCTION_PROTO));
-  // FunctionType
-  Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // ReturnType
-  Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // NoReturn
-  Abv->Add(BitCodeAbbrevOp(0));                         // HasRegParm
-  Abv->Add(BitCodeAbbrevOp(0));                         // RegParm
-  Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // CC
-  Abv->Add(BitCodeAbbrevOp(0));                         // ProducesResult
-  Abv->Add(BitCodeAbbrevOp(0));                         // NoCallerSavedRegs
-  Abv->Add(BitCodeAbbrevOp(0));                         // NoCfCheck
-  Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // CmseNSCall
-  // FunctionProtoType
-  Abv->Add(BitCodeAbbrevOp(0));                         // IsVariadic
-  Abv->Add(BitCodeAbbrevOp(0));                         // HasTrailingReturn
-  Abv->Add(BitCodeAbbrevOp(0));                         // TypeQuals
-  Abv->Add(BitCodeAbbrevOp(0));                         // RefQualifier
-  Abv->Add(BitCodeAbbrevOp(EST_None));                  // ExceptionSpec
-  Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // NumParams
-  Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
-  Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Params
-  TypeFunctionProtoAbbrev = Stream.EmitAbbrev(std::move(Abv));
 }
 
 //===----------------------------------------------------------------------===//