diff --git a/clang/lib/Serialization/ASTReaderDecl.cpp b/clang/lib/Serialization/ASTReaderDecl.cpp
index 76032aa836b507..3de9d327f1b3bc 100644
--- a/clang/lib/Serialization/ASTReaderDecl.cpp
+++ b/clang/lib/Serialization/ASTReaderDecl.cpp
@@ -794,15 +794,12 @@ void ASTDeclReader::VisitEnumDecl(EnumDecl *ED) {
   BitsUnpacker EnumDeclBits(Record.readInt());
   ED->setNumPositiveBits(EnumDeclBits.getNextBits(/*Width=*/8));
   ED->setNumNegativeBits(EnumDeclBits.getNextBits(/*Width=*/8));
-  bool ShouldSkipCheckingODR = EnumDeclBits.getNextBit();
   ED->setScoped(EnumDeclBits.getNextBit());
   ED->setScopedUsingClassTag(EnumDeclBits.getNextBit());
   ED->setFixed(EnumDeclBits.getNextBit());
 
-  if (!ShouldSkipCheckingODR) {
-    ED->setHasODRHash(true);
-    ED->ODRHash = Record.readInt();
-  }
+  ED->setHasODRHash(true);
+  ED->ODRHash = Record.readInt();
 
   // If this is a definition subject to the ODR, and we already have a
   // definition, merge this one into it.
@@ -864,9 +861,6 @@ ASTDeclReader::VisitRecordDeclImpl(RecordDecl *RD) {
 
 void ASTDeclReader::VisitRecordDecl(RecordDecl *RD) {
   VisitRecordDeclImpl(RD);
-  // We should only reach here if we're in C/Objective-C. There is no
-  // global module fragment.
-  assert(!shouldSkipCheckingODR(RD));
   RD->setODRHash(Record.readInt());
 
   // Maintain the invariant of a redeclaration chain containing only
@@ -1066,7 +1060,6 @@ void ASTDeclReader::VisitFunctionDecl(FunctionDecl *FD) {
 
   FD->setCachedLinkage((Linkage)FunctionDeclBits.getNextBits(/*Width=*/3));
   FD->setStorageClass((StorageClass)FunctionDeclBits.getNextBits(/*Width=*/3));
-  bool ShouldSkipCheckingODR = FunctionDeclBits.getNextBit();
   FD->setInlineSpecified(FunctionDeclBits.getNextBit());
   FD->setImplicitlyInline(FunctionDeclBits.getNextBit());
   FD->setHasSkippedBody(FunctionDeclBits.getNextBit());
@@ -1096,10 +1089,8 @@ void ASTDeclReader::VisitFunctionDecl(FunctionDecl *FD) {
   if (FD->isExplicitlyDefaulted())
     FD->setDefaultLoc(readSourceLocation());
 
-  if (!ShouldSkipCheckingODR) {
-    FD->ODRHash = Record.readInt();
-    FD->setHasODRHash(true);
-  }
+  FD->ODRHash = Record.readInt();
+  FD->setHasODRHash(true);
 
   if (FD->isDefaulted() || FD->isDeletedAsWritten()) {
     // If 'Info' is nonzero, we need to read an DefaultedOrDeletedInfo; if,
@@ -1971,8 +1962,6 @@ void ASTDeclReader::ReadCXXDefinitionData(
 
   BitsUnpacker CXXRecordDeclBits = Record.readInt();
 
-  bool ShouldSkipCheckingODR = CXXRecordDeclBits.getNextBit();
-
 #define FIELD(Name, Width, Merge)                                              \
   if (!CXXRecordDeclBits.canGetNextNBits(Width))                         \
     CXXRecordDeclBits.updateValue(Record.readInt());                           \
@@ -1981,12 +1970,9 @@ void ASTDeclReader::ReadCXXDefinitionData(
 #include "clang/AST/CXXRecordDeclDefinitionBits.def"
 #undef FIELD
 
-  // We only perform ODR checks for decls not in GMF.
-  if (!ShouldSkipCheckingODR) {
-    // Note: the caller has deserialized the IsLambda bit already.
-    Data.ODRHash = Record.readInt();
-    Data.HasODRHash = true;
-  }
+  // Note: the caller has deserialized the IsLambda bit already.
+  Data.ODRHash = Record.readInt();
+  Data.HasODRHash = true;
 
   if (Record.readInt()) {
     Reader.DefinitionSource[D] =
diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index 5b5b468532f324..c78d8943d6d92e 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -6543,9 +6543,6 @@ void ASTRecordWriter::AddCXXDefinitionData(const CXXRecordDecl *D) {
 
   BitsPacker DefinitionBits;
 
-  bool ShouldSkipCheckingODR = shouldSkipCheckingODR(D);
-  DefinitionBits.addBit(ShouldSkipCheckingODR);
-
 #define FIELD(Name, Width, Merge)                                              \
   if (!DefinitionBits.canWriteNextNBits(Width)) {                              \
     Record->push_back(DefinitionBits);                                         \
@@ -6558,11 +6555,9 @@ void ASTRecordWriter::AddCXXDefinitionData(const CXXRecordDecl *D) {
 
   Record->push_back(DefinitionBits);
 
-  // We only perform ODR checks for decls not in GMF.
-  if (!ShouldSkipCheckingODR)
-    // getODRHash will compute the ODRHash if it has not been previously
-    // computed.
-    Record->push_back(D->getODRHash());
+  // getODRHash will compute the ODRHash if it has not been previously
+  // computed.
+  Record->push_back(D->getODRHash());
 
   bool ModulesDebugInfo =
       Writer->Context->getLangOpts().ModulesDebugInfo && !D->isDependentType();
diff --git a/clang/lib/Serialization/ASTWriterDecl.cpp b/clang/lib/Serialization/ASTWriterDecl.cpp
index 5dff0cec5c0ea0..17c774038571ef 100644
--- a/clang/lib/Serialization/ASTWriterDecl.cpp
+++ b/clang/lib/Serialization/ASTWriterDecl.cpp
@@ -527,16 +527,12 @@ void ASTDeclWriter::VisitEnumDecl(EnumDecl *D) {
   BitsPacker EnumDeclBits;
   EnumDeclBits.addBits(D->getNumPositiveBits(), /*BitWidth=*/8);
   EnumDeclBits.addBits(D->getNumNegativeBits(), /*BitWidth=*/8);
-  bool ShouldSkipCheckingODR = shouldSkipCheckingODR(D);
-  EnumDeclBits.addBit(ShouldSkipCheckingODR);
   EnumDeclBits.addBit(D->isScoped());
   EnumDeclBits.addBit(D->isScopedUsingClassTag());
   EnumDeclBits.addBit(D->isFixed());
   Record.push_back(EnumDeclBits);
 
-  // We only perform ODR checks for decls not in GMF.
-  if (!ShouldSkipCheckingODR)
-    Record.push_back(D->getODRHash());
+  Record.push_back(D->getODRHash());
 
   if (MemberSpecializationInfo *MemberInfo = D->getMemberSpecializationInfo()) {
     Record.AddDeclRef(MemberInfo->getInstantiatedFrom());
@@ -553,7 +549,7 @@ void ASTDeclWriter::VisitEnumDecl(EnumDecl *D) {
       !D->isTopLevelDeclInObjCContainer() &&
       !CXXRecordDecl::classofKind(D->getKind()) &&
       !D->getIntegerTypeSourceInfo() && !D->getMemberSpecializationInfo() &&
-      !needsAnonymousDeclarationNumber(D) && !shouldSkipCheckingODR(D) &&
+      !needsAnonymousDeclarationNumber(D) &&
       D->getDeclName().getNameKind() == DeclarationName::Identifier)
     AbbrevToUse = Writer.getDeclEnumAbbrev();
 
@@ -719,8 +715,6 @@ void ASTDeclWriter::VisitFunctionDecl(FunctionDecl *D) {
   // FIXME: stable encoding
   FunctionDeclBits.addBits(llvm::to_underlying(D->getLinkageInternal()), 3);
   FunctionDeclBits.addBits((uint32_t)D->getStorageClass(), /*BitWidth=*/3);
-  bool ShouldSkipCheckingODR = shouldSkipCheckingODR(D);
-  FunctionDeclBits.addBit(ShouldSkipCheckingODR);
   FunctionDeclBits.addBit(D->isInlineSpecified());
   FunctionDeclBits.addBit(D->isInlined());
   FunctionDeclBits.addBit(D->hasSkippedBody());
@@ -746,9 +740,7 @@ void ASTDeclWriter::VisitFunctionDecl(FunctionDecl *D) {
   if (D->isExplicitlyDefaulted())
     Record.AddSourceLocation(D->getDefaultLoc());
 
-  // We only perform ODR checks for decls not in GMF.
-  if (!ShouldSkipCheckingODR)
-    Record.push_back(D->getODRHash());
+  Record.push_back(D->getODRHash());
 
   if (D->isDefaulted() || D->isDeletedAsWritten()) {
     if (auto *FDI = D->getDefalutedOrDeletedInfo()) {
@@ -1560,8 +1552,7 @@ void ASTDeclWriter::VisitCXXMethodDecl(CXXMethodDecl *D) {
       D->getFirstDecl() == D->getMostRecentDecl() && !D->isInvalidDecl() &&
       !D->hasAttrs() && !D->isTopLevelDeclInObjCContainer() &&
       D->getDeclName().getNameKind() == DeclarationName::Identifier &&
-      !shouldSkipCheckingODR(D) && !D->hasExtInfo() &&
-      !D->isExplicitlyDefaulted()) {
+      !D->hasExtInfo() && !D->isExplicitlyDefaulted()) {
     if (D->getTemplatedKind() == FunctionDecl::TK_NonTemplate ||
         D->getTemplatedKind() == FunctionDecl::TK_FunctionTemplate ||
         D->getTemplatedKind() == FunctionDecl::TK_MemberSpecialization ||