diff --git a/llvm/lib/Linker/LinkModules.cpp b/llvm/lib/Linker/LinkModules.cpp
--- a/llvm/lib/Linker/LinkModules.cpp
+++ b/llvm/lib/Linker/LinkModules.cpp
@@ -24,7 +24,7 @@
 
 namespace {
 
-enum class LinkFrom { Dst, Src };
+enum class LinkFrom { Dst, Src, Both };
 
 /// This is an implementation class for the LinkModules function, which is the
 /// entrypoint for this file.
@@ -105,7 +105,7 @@
   void dropReplacedComdat(GlobalValue &GV,
                           const DenseSet<const Comdat *> &ReplacedDstComdats);
 
-  bool linkIfNeeded(GlobalValue &GV);
+  bool linkIfNeeded(GlobalValue &GV, SmallVectorImpl<GlobalValue *> &GVToClone);
 
 public:
   ModuleLinker(IRMover &Mover, std::unique_ptr<Module> SrcM, unsigned Flags,
@@ -179,25 +179,9 @@
     // Go with Dst.
     From = LinkFrom::Dst;
     break;
-  case Comdat::SelectionKind::NoDeduplicate: {
-    const GlobalVariable *DstGV;
-    const GlobalVariable *SrcGV;
-    if (getComdatLeader(DstM, ComdatName, DstGV) ||
-        getComdatLeader(*SrcM, ComdatName, SrcGV))
-      return true;
-
-    if (SrcGV->isWeakForLinker()) {
-      // Go with Dst.
-      From = LinkFrom::Dst;
-    } else if (DstGV->isWeakForLinker()) {
-      // Go with Src.
-      From = LinkFrom::Src;
-    } else {
-      return emitError("Linking COMDATs named '" + ComdatName +
-                       "': nodeduplicate has been violated!");
-    }
+  case Comdat::SelectionKind::NoDeduplicate:
+    From = LinkFrom::Both;
     break;
-  }
   case Comdat::SelectionKind::ExactMatch:
   case Comdat::SelectionKind::Largest:
   case Comdat::SelectionKind::SameSize: {
@@ -342,7 +326,8 @@
                    "': symbol multiply defined!");
 }
 
-bool ModuleLinker::linkIfNeeded(GlobalValue &GV) {
+bool ModuleLinker::linkIfNeeded(GlobalValue &GV,
+                                SmallVectorImpl<GlobalValue *> &GVToClone) {
   GlobalValue *DGV = getLinkedToGlobal(&GV);
 
   if (shouldLinkOnlyNeeded()) {
@@ -404,6 +389,8 @@
   bool LinkFromSrc = true;
   if (DGV && shouldLinkFromSource(LinkFromSrc, *DGV, GV))
     return true;
+  if (DGV && ComdatFrom == LinkFrom::Both)
+    GVToClone.push_back(LinkFromSrc ? DGV : &GV);
   if (LinkFromSrc)
     ValuesToLink.insert(&GV);
   return false;
@@ -530,22 +517,45 @@
 
   // Insert all of the globals in src into the DstM module... without linking
   // initializers (which could refer to functions not yet mapped over).
+  SmallVector<GlobalValue *, 0> GVToClone;
   for (GlobalVariable &GV : SrcM->globals())
-    if (linkIfNeeded(GV))
+    if (linkIfNeeded(GV, GVToClone))
       return true;
 
   for (Function &SF : *SrcM)
-    if (linkIfNeeded(SF))
+    if (linkIfNeeded(SF, GVToClone))
       return true;
 
   for (GlobalAlias &GA : SrcM->aliases())
-    if (linkIfNeeded(GA))
+    if (linkIfNeeded(GA, GVToClone))
       return true;
 
   for (GlobalIFunc &GI : SrcM->ifuncs())
-    if (linkIfNeeded(GI))
+    if (linkIfNeeded(GI, GVToClone))
       return true;
 
+  // For a variable in a comdat nodeduplicate, its initializer should be
+  // preserved (its content may be implicitly used by other members) even if
+  // symbol resolution does not pick it. Clone it into an unnamed private
+  // variable.
+  for (GlobalValue *GV : GVToClone) {
+    if (auto *Var = dyn_cast<GlobalVariable>(GV)) {
+      auto *NewVar = new GlobalVariable(*Var->getParent(), Var->getValueType(),
+                                        Var->isConstant(), Var->getLinkage(),
+                                        Var->getInitializer());
+      NewVar->copyAttributesFrom(Var);
+      NewVar->setVisibility(GlobalValue::DefaultVisibility);
+      NewVar->setLinkage(GlobalValue::PrivateLinkage);
+      NewVar->setDSOLocal(true);
+      NewVar->setComdat(Var->getComdat());
+      if (Var->getParent() != &Mover.getModule())
+        ValuesToLink.insert(NewVar);
+    } else {
+      emitError("linking '" + GV->getName() +
+                "': non-variables in comdat nodeduplicate are not handled");
+    }
+  }
+
   for (unsigned I = 0; I < ValuesToLink.size(); ++I) {
     GlobalValue *GV = ValuesToLink[I];
     const Comdat *SC = GV->getComdat();
diff --git a/llvm/test/Linker/comdat-nodeduplicate.ll b/llvm/test/Linker/comdat-nodeduplicate.ll
--- a/llvm/test/Linker/comdat-nodeduplicate.ll
+++ b/llvm/test/Linker/comdat-nodeduplicate.ll
@@ -1,18 +1,21 @@
 ; RUN: rm -rf %t && split-file %s %t
 ; RUN: not llvm-link -S %t/1.ll %t/1-aux.ll 2>&1 | FileCheck %s
 
-; CHECK: error: Linking COMDATs named 'foo': nodeduplicate has been violated!
+; CHECK: Linking globals named 'foo': symbol multiply defined!
 
 ; RUN: llvm-link -S %t/2.ll %t/2-aux.ll | FileCheck %s --check-prefix=CHECK2
 ; RUN: llvm-link -S %t/2-aux.ll %t/2.ll | FileCheck %s --check-prefix=CHECK2
 
-; CHECK2-DAG: @foo = global i64 2, section "data", comdat, align 8
-; CHECK2-DAG: @bar = weak global i64 0, section "cnts", comdat($foo)
+; CHECK2-DAG: @[[#]] = private global i64 0, section "data", comdat($foo)
+; CHECK2-DAG: @[[#]] = private global i64 0, section "cnts", comdat($foo)
+; CHECK2-DAG: @foo = hidden global i64 2, section "data", comdat, align 8
+; CHECK2-DAG: @bar = dso_local global i64 3, section "cnts", comdat($foo), align 16
 ; CHECK2-DAG: @qux = weak_odr global i64 4, comdat($foo)
+; CHECK2-DAG: @fred = linkonce global i64 5, comdat($foo)
 
-; RUN: not llvm-link -S %t/non-var.ll %t/non-var.ll 2>&1 | FileCheck %s --check-prefix=NONVAR
+; RUN: llvm-link -S %t/non-var.ll %t/non-var.ll 2>&1 | FileCheck %s --check-prefix=NONVAR
 
-; NONVAR: error: Linking COMDATs named 'foo': GlobalVariable required for data dependent selection!
+; NONVAR: linking 'foo': non-variables in comdat nodeduplicate are not handled
 
 ;--- 1.ll
 $foo = comdat nodeduplicate
@@ -30,7 +33,7 @@
 
 ;--- 2-aux.ll
 $foo = comdat nodeduplicate
-@foo = weak global i64 0, section "data", comdat($foo)
+@foo = weak hidden global i64 0, section "data", comdat($foo)
 @bar = dso_local global i64 3, section "cnts", comdat($foo), align 16
 @fred = linkonce global i64 5, comdat($foo)