diff --git a/clang/lib/Serialization/ASTReaderDecl.cpp b/clang/lib/Serialization/ASTReaderDecl.cpp
index 0cf9afb..f3eab2e 100644
--- a/clang/lib/Serialization/ASTReaderDecl.cpp
+++ b/clang/lib/Serialization/ASTReaderDecl.cpp
@@ -792,6 +792,7 @@
   FD->IsConstexpr = Record.readInt();
   FD->UsesSEHTry = Record.readInt();
   FD->HasSkippedBody = Record.readInt();
+  FD->IsMultiVersion = Record.readInt();
   FD->IsLateTemplateParsed = Record.readInt();
   FD->setCachedLinkage(Linkage(Record.readInt()));
   FD->EndRangeLoc = ReadSourceLocation();
@@ -2818,6 +2819,21 @@
                         CtorY->getInheritedConstructor().getConstructor()))
         return false;
     }
+
+    if (FuncX->isMultiVersion() != FuncY->isMultiVersion())
+      return false;
+
+    // Multiversioned functions with different feature strings are represented
+    // as separate declarations.
+    if (FuncX->isMultiVersion()) {
+      const auto *TAX = FuncX->getAttr<TargetAttr>();
+      const auto *TAY = FuncY->getAttr<TargetAttr>();
+      assert(TAX && TAY && "Multiversion Function without target attribute");
+
+      if (TAX->getFeaturesStr() != TAY->getFeaturesStr())
+        return false;
+    }
+
     ASTContext &C = FuncX->getASTContext();
     if (!C.hasSameType(FuncX->getType(), FuncY->getType())) {
       // We can get functions with different types on the redecl chain in C++17
diff --git a/clang/lib/Serialization/ASTWriterDecl.cpp b/clang/lib/Serialization/ASTWriterDecl.cpp
index 341f0e1..c2c6fd4 100644
--- a/clang/lib/Serialization/ASTWriterDecl.cpp
+++ b/clang/lib/Serialization/ASTWriterDecl.cpp
@@ -534,6 +534,7 @@
   Record.push_back(D->IsConstexpr);
   Record.push_back(D->UsesSEHTry);
   Record.push_back(D->HasSkippedBody);
+  Record.push_back(D->IsMultiVersion);
   Record.push_back(D->IsLateTemplateParsed);
   Record.push_back(D->getLinkageInternal());
   Record.AddSourceLocation(D->getLocEnd());
@@ -2072,6 +2073,7 @@
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Constexpr
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // UsesSEHTry
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // SkippedBody
+  Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // MultiVersion
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // LateParsed
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // Linkage
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // LocEnd