Index: clang/docs/ReleaseNotes.rst
===================================================================
--- clang/docs/ReleaseNotes.rst
+++ clang/docs/ReleaseNotes.rst
@@ -435,6 +435,10 @@
   It can be used to writing conditionally constexpr code that uses builtins.
 - The time profiler (using ``-ftime-trace`` option) now traces various constant
   evaluation events.
+- Clang can now generate a PCH when using ``-fdelayed-template-parsing`` for
+  code with templates containing loop hint pragmas, OpenMP pragmas, and
+  ``#pragma unused``.
+
 
 New Compiler Flags
 ------------------
Index: clang/include/clang/Lex/Token.h
===================================================================
--- clang/include/clang/Lex/Token.h
+++ clang/include/clang/Lex/Token.h
@@ -15,6 +15,7 @@
 
 #include "clang/Basic/SourceLocation.h"
 #include "clang/Basic/TokenKinds.h"
+#include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/StringRef.h"
 #include <cassert>
 
@@ -330,6 +331,12 @@
   bool FoundElse;
 };
 
+// Extra information needed for annonation tokens.
+struct PragmaLoopHintInfo {
+  Token PragmaName;
+  Token Option;
+  ArrayRef<Token> Toks;
+};
 } // end namespace clang
 
 #endif // LLVM_CLANG_LEX_TOKEN_H
Index: clang/include/clang/Serialization/ASTBitCodes.h
===================================================================
--- clang/include/clang/Serialization/ASTBitCodes.h
+++ clang/include/clang/Serialization/ASTBitCodes.h
@@ -41,7 +41,7 @@
 /// Version 4 of AST files also requires that the version control branch and
 /// revision match exactly, since there is no backward compatibility of
 /// AST files at this time.
-const unsigned VERSION_MAJOR = 24;
+const unsigned VERSION_MAJOR = 25;
 
 /// AST file minor version number supported by this version of
 /// Clang.
Index: clang/lib/Parse/ParsePragma.cpp
===================================================================
--- clang/lib/Parse/ParsePragma.cpp
+++ clang/lib/Parse/ParsePragma.cpp
@@ -1293,14 +1293,6 @@
   return true;
 }
 
-namespace {
-struct PragmaLoopHintInfo {
-  Token PragmaName;
-  Token Option;
-  ArrayRef<Token> Toks;
-};
-} // end anonymous namespace
-
 static std::string PragmaLoopHintString(Token PragmaName, Token Option) {
   StringRef Str = PragmaName.getIdentifierInfo()->getName();
   std::string ClangLoopStr("clang loop ");
Index: clang/lib/Serialization/ASTReader.cpp
===================================================================
--- clang/lib/Serialization/ASTReader.cpp
+++ clang/lib/Serialization/ASTReader.cpp
@@ -1663,11 +1663,38 @@
   Token Tok;
   Tok.startToken();
   Tok.setLocation(ReadSourceLocation(F, Record, Idx));
-  Tok.setLength(Record[Idx++]);
-  if (IdentifierInfo *II = getLocalIdentifier(F, Record[Idx++]))
-    Tok.setIdentifierInfo(II);
   Tok.setKind((tok::TokenKind)Record[Idx++]);
   Tok.setFlag((Token::TokenFlags)Record[Idx++]);
+
+  if (Tok.isAnnotation()) {
+    Tok.setAnnotationEndLoc(ReadSourceLocation(F, Record, Idx));
+    switch (Tok.getKind()) {
+    case tok::annot_pragma_loop_hint: {
+      auto *Info = new (PP.getPreprocessorAllocator()) PragmaLoopHintInfo;
+      Info->PragmaName = ReadToken(F, Record, Idx);
+      Info->Option = ReadToken(F, Record, Idx);
+      unsigned NumTokens = Record[Idx++];
+      SmallVector<Token, 4> Toks;
+      Toks.reserve(NumTokens);
+      for (unsigned I = 0; I < NumTokens; ++I)
+        Toks.push_back(ReadToken(F, Record, Idx));
+      Info->Toks = llvm::makeArrayRef(Toks).copy(PP.getPreprocessorAllocator());
+      Tok.setAnnotationValue(static_cast<void *>(Info));
+      break;
+    }
+    // Some annotation tokens do not use the PtrData field.
+    case tok::annot_pragma_openmp:
+    case tok::annot_pragma_openmp_end:
+    case tok::annot_pragma_unused:
+      break;
+    default:
+      llvm_unreachable("missing deserialization code for annotation token");
+    }
+  } else {
+    Tok.setLength(Record[Idx++]);
+    if (IdentifierInfo *II = getLocalIdentifier(F, Record[Idx++]))
+      Tok.setIdentifierInfo(II);
+  }
   return Tok;
 }
 
Index: clang/lib/Serialization/ASTWriter.cpp
===================================================================
--- clang/lib/Serialization/ASTWriter.cpp
+++ clang/lib/Serialization/ASTWriter.cpp
@@ -4362,15 +4362,37 @@
 
 void ASTWriter::AddToken(const Token &Tok, RecordDataImpl &Record) {
   AddSourceLocation(Tok.getLocation(), Record);
-  Record.push_back(Tok.getLength());
-
-  // FIXME: When reading literal tokens, reconstruct the literal pointer
-  // if it is needed.
-  AddIdentifierRef(Tok.getIdentifierInfo(), Record);
   // FIXME: Should translate token kind to a stable encoding.
   Record.push_back(Tok.getKind());
   // FIXME: Should translate token flags to a stable encoding.
   Record.push_back(Tok.getFlags());
+
+  if (Tok.isAnnotation()) {
+    AddSourceLocation(Tok.getAnnotationEndLoc(), Record);
+    switch (Tok.getKind()) {
+    case tok::annot_pragma_loop_hint: {
+      auto *Info = static_cast<PragmaLoopHintInfo *>(Tok.getAnnotationValue());
+      AddToken(Info->PragmaName, Record);
+      AddToken(Info->Option, Record);
+      Record.push_back(Info->Toks.size());
+      for (const auto &T : Info->Toks)
+        AddToken(T, Record);
+      break;
+    }
+    // Some annotation tokens do not use the PtrData field.
+    case tok::annot_pragma_openmp:
+    case tok::annot_pragma_openmp_end:
+    case tok::annot_pragma_unused:
+      break;
+    default:
+      llvm_unreachable("missing serialization code for annotation token");
+    }
+  } else {
+    Record.push_back(Tok.getLength());
+    // FIXME: When reading literal tokens, reconstruct the literal pointer if it
+    // is needed.
+    AddIdentifierRef(Tok.getIdentifierInfo(), Record);
+  }
 }
 
 void ASTWriter::AddString(StringRef Str, RecordDataImpl &Record) {
Index: clang/test/PCH/delayed-template-with-pragma.cpp
===================================================================
--- /dev/null
+++ clang/test/PCH/delayed-template-with-pragma.cpp
@@ -0,0 +1,36 @@
+// RUN: %clang_cc1 -fopenmp -emit-pch -o %t.pch %s
+// RUN: %clang_cc1 -fopenmp -fdelayed-template-parsing -emit-pch -o %t.delayed.pch %s
+// RUN: %clang_cc1 -DMAIN_FILE -fopenmp -include-pch %t.pch \
+// RUN:   -emit-llvm -o - %s -fopenmp | FileCheck %s
+// RUN: %clang_cc1 -DMAIN_FILE -fopenmp -fdelayed-template-parsing -verify \
+// RUN:   -Wunused-variable -include-pch %t.delayed.pch \
+// RUN:   -emit-llvm -o - %s | FileCheck %s
+
+#ifndef MAIN_FILE
+template <typename T>
+void a(T t) {
+  #pragma clang loop unroll_count(4)
+  for(int i=0;i<8;++i) {}
+  #pragma omp simd
+  for(int i=0;i<8;++i) {}
+  {
+    int x, y, z, zz;
+    #pragma unused(x)
+    #pragma unused(y, z)
+  }
+}
+#else
+// CHECK: !llvm.loop !3
+// CHECK: !llvm.loop !7
+// CHECK: !3 = distinct !{!3, !4, !5}
+// CHECK: !4 = !{!"llvm.loop.mustprogress"}
+// CHECK: !5 = !{!"llvm.loop.unroll.count", i32 4}
+// CHECK: !7 = distinct !{!7, !8, !9}
+// CHECK: !8 = !{!"llvm.loop.parallel_accesses", !6}
+// CHECK: !9 = !{!"llvm.loop.vectorize.enable", i1 true}
+// expected-warning@17 {{unused variable 'zz'}}
+void foo()
+{
+  a(1);
+}
+#endif